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So I've been reading old threads about Weber IDF carbs and the "Cain" manifold. What happened to this concept? It appears that there aren't too many people who have done this in a Pantera. I don't know if it's for me or much about it, but I'd like to learn more.

Corey
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With gas prices rising steadily, and my plans to drive 6018 all around North America, I have reservations about using IR induction. Theoretically if a person restrains their right foot, the fuel mileage shouldn't be too bad. But it never seems to work out that way.

The manifold is available, but priced much higher than what the manufacturer (Aussie Speed) originally quoted.

Aussie Speed 351C Weber Manifold

Weber IDF

-G
No IDF, nor a Cain manifold, but might give you an idea how things might look like Cool

Little Weber manifolds are cast and machined these days, which might influence the price in a for us negative way. Prices went up at the time I ordered mine, and had to wait months for the next batch to be cast.

Been considering injection too (Weber like ITB's), but went for the real 70's thing after all.

Custom build by Jim Inglese ( http://www.jiminglese.com/index.html ).

Paint is a 68 Mustang color, called "Sunlit gold". Some details changed to as the original kit was (like the stacks and fuel lines), and some more still will be changed (like the linkage set-up). Images of the kit with the original stacks can bee found on Jim's site.

I did not install the kit yet - it stays on the shelf waiting for a new engine to be fitted on Big Grin



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The reason, I think, you don't see virtually any 32 IDF Clevelands running around is because 32's are way too small for a 351.

Individual runner manifolds have much different cfm demands then a single plenum intake does.

Throw away that Holley cfm chart for IR's.

The 48's were really developed for Shelby's 289 Cobras.

They start to show restriction issues at around 5,500 rpm's on a 289. That's with 42mm chokes too.

58mm IDA's were actually developed specifically for 427 comp Cobras. Not many were made. Some say only four complete serial numbered sets.

The 351c under comp demands needs something like a 54 of 55 mm throttle. Actually the number is probably the size of the intake valve seat opening or there abouts?

54.6mm, plus or minus, is the maximum the 48 IDA manifold ports can be bored out to and realistically the Hall manifold is the only one available.

That manifold has about that limitation of porting as well.

There are two other IDA manifolds that were made for the 351c that I know of. The Holman-Moody, and the Detomaso lettered one.

Hall was the only individual I know of that had a DT manifold. Years ago I wrote to DT inquiring and I still have the letter somewhere but the entire setup from them was about $865, circa 1980. Coulda', wouda', shouda'. Roll Eyes

I have never had either in my hands but was told that the HM was the first to be made, the DT is a copy of it, and the Hall is a reinforced version of the DT.

So in a nutshell, the 32's are too small and therefore have little attraction to someone who is looking for a max effort performance induction system.

Of course this is all from my perspective which admittedly I am quite a bent individual to begin with, so you need to keep that in mind and take what I say with a grain of salt?
Last edited by panteradoug
The picture in this thread interested me. It appears that with the Cain manifold, the 48 IDF's sit under the engine screen with air cleaners. I love the look of Weber carbs but never really liked the idea of running without an air cleaner. If I argue that the air cleaners are a great idea, someone will report me to the moderator and I'm gonna get booted for arguing with someone.

Jack D. also posted about potential fire hazards if Weber carbs are used with air cleaners due to fuel reversion. I think you'd have to set up the engine for this by choosing or having a custom low-overlap cam made specifically for this.
Last edited by coreyprice
> Theoretically if a person restrains their right foot, the fuel mileage
> shouldn't be too bad.

Fuel economy can be better than a 4 barrel if properly calibrated. Vizard
reported 18 to 20 MPG on his SBC-powered shop truck with 48mm Webers.

> The 48's were really developed for Shelby's 289 Cobras. They start to show
> restriction issues at around 5,500 rpm's on a 289.

Vizard's testing on a 350 SBC found that 48mm Webers on a down draft IR
intake showed the Webers to be superior in peak power up to around 480 HP,
after which a larger 4 barrel carb on a plenum intake would make more peak
power but not necessarily better average. The independent runner manifolding
provides better power in low and mid-range so the cross-over point for
average power is higher.

Dan Jones
quote:
Originally posted by Daniel_Jones:
> Theoretically if a person restrains their right foot, the fuel mileage
> shouldn't be too bad.

Fuel economy can be better than a 4 barrel if properly calibrated. Vizard
reported 18 to 20 MPG on his SBC-powered shop truck with 48mm Webers.

> The 48's were really developed for Shelby's 289 Cobras. They start to show
> restriction issues at around 5,500 rpm's on a 289.

Vizard's testing on a 350 SBC found that 48mm Webers on a down draft IR
intake showed the Webers to be superior in peak power up to around 480 HP,
after which a larger 4 barrel carb on a plenum intake would make more peak
power but not necessarily better average. The independent runner manifolding
provides better power in low and mid-range so the cross-over point for
average power is higher.

Dan Jones


Can't argue with either. Best mileage I've seen with the Webers on my car is 15. Best with a 4179 Holley was 13-14. Of course it is very difficult not to put your foot into either.

I would say that the Webers on an IR (people have put them on single plenum manifolds) have a significantly better throttle response the a single Holley, at any rpm or speed. At least that is what I have experienced.

Over 100 mph, nothing pulls like Webers except a supercharger and possibly nitrous.

When you are driving the car, rather then having the engine on a dyno, I think the power with the Webers is much better over 100 mph then the Holley.

HOWEVER, I am usually trying hard just to hold on, trying not to blink as my eyes are watering from bouncing around, rather then sit there thinking, are the Holley and the Webers about the same?

Do you have a print out of that dyno run with the SB Chevy, Webers vs. Big Holley? I'd like to see that.

I have a feeling though that a nice set of two Holleys will yield the response of the Webers with the top end of the big Holley, and better overall drive-ability then either.

That certainly appears to be the case on my 347.

Don't forget that initially you are driving on just a 2v until about 3200rpms, and the secondaries are vacuum.

Lack of a manifold for the C of course is the killer to my theory for now though...just for now. Wink
quote:
Originally posted by Corey Price:
The picture in this thread interested me. It appears that with the Cain manifold, the 48 IDF's sit under the engine screen with air cleaners. I love the look of Weber carbs but never really liked the idea of running without an air cleaner.

Jack D. also posted about potential fire hazards if Weber carbs are used with air cleaners due to fuel reversion. I think you'd have to set up the engine for this by choosing or having a custom low-overlap cam made specifically for this.


In my experience the carbs don't even like having screens over them. The difference with and without is very noticible.

Also, I may be wrong again, but I haven't seen IDF's larger then 32's. Have you seen 48 IDF's?

If you look at some of the '60s muscle car tests, it was very common to pick up a few 10ths by taking off the air cleaner assembly.

To me it feels like you easily are picking up something like 80 to 100 hp in a 1/4 mile run.

All carbs like to run around naked.
I spoke with Jim Inglese about the concept, and he said it's possible. Jim said that he doesn't like the IDF's as much as the IDA's, but the IDF's are just fine. In fact, the IDF's are cheaper than the IDA's. Too bad the administrator likes these things as I think they're sexy.

Long story short, the IDF's would be fine and can be tuned very nicely. It's not EFI, but here's a guy who will taylor a setup to your engine for maybe still half the cost of the typical IR EFI setup done professionally.
Last edited by coreyprice
Can't really comment of the IDFs. No experience with them at all.
Considering though that the Australian manifolds are for iron 2v heads, I'd say there are no manifolds for the 4v's.
My thought is don't run 2v head stuff unless for some reason you have to.
Port flow on the newer "good" aluminum 4v heads is 330cfm ish. Do those Aussie 2v manifolds flow that? I doubt it? Look at the ports.
As it is Hall's manifolds for the 4v and SVO are the only two really available.
I heard Falconner & Dunn had built one, but one of them 10 years ago said, no, they never had.
I suppose if you can weld, you could make a sheet metal manifold for the IDFs on a 4v I suppose?
The IDAs really are streetable. There isn't much to be gained by running IDFs?
The IDA transition "issue" can be minimized by adding a third transition hole in the carb.
Still there, but almost gone.
The issue for me with Webers on the Pantera is you can't wssh the car unless you cap the velocity stacks. PITA. What do you do if it rains with them? Instant water injection?
Last edited by panteradoug
Great thread that gets me thinking about putting webers on the cleveland again. After doing a set of 48 IDA webers on a small block chevy and after personally tuning a brand new set (not as hard as you would think), me personally, I think I'd bite the bullet and let Jim Inglese do the setup (IDA's or IDF's)if I didn't want to jerk around with it for months and months. But then that is personal preference...if you want a project that consume lots of time there isn't one that is as much fun as putting on Webers.

Keep in mind that getting to the carbs will be a real pain in you back, literally! I did my first set on a mid engine race car where the entire back body section was removable. Everything was right there. On a Pantera....not so much, and you will be taking the carbs apart a lot...four times for every change. Possibly the easiest way to reach the carbs in a Pantera would be to remove the deck lid and laydown on the roof with you feet going toward the front of the car. I'm not joking. It got to be similar to adjusting solid lifters.

If you can get the initial setup for jetting from someone else that's got a set running well ON A CLEVELAND as a starting point (thank you Doug!), then why not save some money, but my guess is if the motor specs aren't identical you'll be making some changes.

I remember doing the IDA's with 44 chokes because many people told me 48's on a on a 360 inch chevy would be too much. There were guys running 427's with 48's. The heads I ran were the off road (as in track)competetion heads from chevy and the motor ran amazingly with 44's in a 11.5-1 compression motor with a mild cam (.520 lift cam). For street cars I remember hearing a lot about IDF's being a smoother transitioning carb from low to higher rpms. There is an additional mid range circuit in the IDF's as I recall and it makes street driving where your going gradually through an RPM range of 2500-3000 rpms smoother. An IDA setup from Inglese shouldn't have that issue. I was able to finally tune out that transition issue.

Haven't seen Jim Inglese's website before....but after poking around it gives me confidence he absolutely knows what he's doing. Make sure you get a GREAT linkage setup...spend extra on a good one. That was one of the issues of the IDA setup on the chevy...the IDA's seem to change ever so slightly, often. It's not that big a deal on a race car because you are usually not idling much, but if it's on a street car and drivablity a stop lights and lower rpm is important, it matters because once carb will get out of sync and throw lower rpm functions off.

Kid, I'm very jealous of your setup....would love to bolt that on to my motor!
Actually the issue with IDA's as would be run on the Hall manifold with linkage is almost eliminated as compared with what you would run on a 289 Cobra.
Some of the linkages tend to twist and get out of adjustment, not from street driving, but from running WOT flat out. When you want to come back to idle the car, that is when you will find out if your linkage is set up correctly.

Most people will build it where they over center it in order to get the car to idle as low as possible. That causes problems because the linkage will not stay there.

As far as getting someone else to do the calibration and forgetting about it from that point on, are you kidding?

The jetting changes from day to day as the weather does.

The air corrector you had in there yesterday at 50f and 20 humidity is now wrong for 95f and 90 humidity today.

Maybe southern California doesn't change like that but anywhere along the east coast of the US will. The changes are often drastic.

I don't know if he still does it but Jim used to send you one size up and one size down along with his dialed in setup.

The real issue with IDAs is that there is just no way that even an average car enthusiast is going to understand what these things are going to run like. You have to experience it for yourself.

I would say that the overall feeling is one of disappointment.

Apparently many people expect the carbs to make their 289 run like a 427? That just ain't going to happen BUT I will say this, driving a set of "well running" Webers is a life experience and regardless how you eventually wind up, i.e., with or without Webers, your life is never going to be the same again.

I think that speaks volumes?

Use Inglese's setup. Then you can bitch to him and not me, LOL! After all, he gets paid for it...I don't!

Best to everyone. Big Grin
Last edited by panteradoug
I did invest in an Innovate LM2 air/fuel ratio meter, which at the same time is a datalogger too, to get my initial set-up going.

As for the linkage, the connection in between the carbs is one thing, the throttle linkage is an other, as I found out, many people have the latter completely wrong. I brought this to JI's attention, and he changed his linkage design as per my recommandations. It is not only JI who had it wrong, I found similar mistakes at other vendors too.
quote:
Originally posted by Kid:
I did invest in an Innovate LM2 air/fuel ratio meter, which at the same time is a datalogger too, to get my initial set-up going.

As for the linkage, the connection in between the carbs is one thing, the throttle linkage is an other, as I found out, many people have the latter completely wrong. I brought this to JI's attention, and he changed his linkage design as per my recommandations. It is not only JI who had it wrong, I found similar mistakes at other vendors too.


The tower in the center is actually correct for the Pantera, since the pedal pulls the carbs.

Many Clevelands are in other cars such as Mustangs and for them the Pantera linkage is wrong.

The tower actually helps since there is nothing to bend in it.

This actually makes the Pantera simpler since you can hook the left side to the right from the rear of the manifold, left to right directly.

I find this helps a lot. I had this setup in my Shelby and the Mustangs need to be controlled from the drivers side of the carbs.

On that setup it is better to have the four carbs all in parallel rather then opposed. I had Inglese's reversing plates on that set up. One side is just a spacer, the other side reverses the carbs so that all four have the fuel inlets on the same side. This simplifies the linkage. For me on that car it was the only way to correct a geometry issue with the linkage. The Pantera with the pull on the bell on the tower doesn't have that problem. There the tower actually can get in the way.

The throttle body peopl use the Hall manifold but mill the tower out and put a vacuum box there with tower on top. Personally I think that is needless, but hey, what do I know about anything? Seems like not much?
Last edited by panteradoug
Yeah I will admit we in SoCal don't have to deal with as many weather changes unless we're going to an elevation location. Once they're set, summer, winter it usually doesn't change.

My linkage was set up with pedal stops at the bottom or WOT and with a giant flex cable that came in from the side...Don't think it could be much simpler in the center of the four carbs. No bell crank mechanism, just a bracket to hold the cable, yet would.

I notice all the current manifolds don't have a vacuum plenum...my manifold was a Mckay made from magnesium...it had about a three inch tall plenum.

Doug I would agree that once you have Webers, there is no substitute.
quote:
Originally posted by Tom@Seal Beach:
Yeah I will admit we in SoCal don't have to deal with as many weather changes unless we're going to an elevation location. Once they're set, summer, winter it usually doesn't change.

My linkage was set up with pedal stops at the bottom or WOT and with a giant flex cable that came in from the side...Don't think it could be much simpler in the center of the four carbs. No bell crank mechanism, just a bracket to hold the cable, yet would.

I notice all the current manifolds don't have a vacuum plenum...my manifold was a Mckay made from magnesium...it had about a three inch tall plenum.

Doug I would agree that once you have Webers, there is no substitute.


I'd like to see a picture of that manifold if you wouldn't mind posting one. Don't recall every seeing one. I have heard of it though.

My setup is out of the car and on the bench at the moment. Anyone want to see it, let me know I'll post a pic.
Some time back I was pulling together a group buy for the Cain manifold and we were getting a small discount for 5, but I struggled to find 5 people who were definitely on board. Since then exchange rates are worse and the manifold price higher.

One prior member of the group buy did tell me at the Fun Rally he was still interested, so if there are a couple more I could resurrect the contact.

The benefit is that 48 IDF's on a Cain manifold will fit under the engine screen and decklid with no cutting required. Also Mark at Aussie Speed confirmed there is enough material in the manifold to port to 4V heads.

I have set of 48IDf's on the shelf, just haven't gotten around to ordering the manifold yet.

Julian
IF you already have IDA's I personally see no point in going to IDFs.
The IDAs can in effect have in intermediate circuit created by adding another transfer slot hole to the carb.
In addition, if you are starting from scratch, electronic fuel injection would be the way to go.
The set up would cost about the same except for the addition of the CPU needed for the FI.
I suppose it all depends on how one conceives of the car as either an up to date ultra modern or a retro, period unit from the early 70s?
No matter which CARB system you choose, you still need to deal with the reversion in the carbs from the cam overlap. Not so on the FI.

Can someone explain what the mass is on the bottom of this manifold casting? To me it looks like an exhaust cross over plenum but there is none on this manifold.

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Doug said "The IDA transition "issue" can be minimized by adding a third transition hole in the carb."
__________________________________________
Doug please explain, I've never heard of that.

Also can anyone give their personal experiences on the IDF's on a Cleveland?

Is the Cain manifold a magnesium or aluminum? Looks like pickled mag...sort of like the McKay magnesium manifold I ran on the SBC. I personally wouldn't want a magnesium manifold on a street driven car. I had to drain the cooling system every time the car sat for more than a day because the magnesium corroded so quickly. A deal killer for a street car driven on a regular basis.

Also, will the IDF's WITH an air cleaner fit under the deck lid?
quote:
Originally posted by Tom@Seal Beach:
Doug said "The IDA transition "issue" can be minimized by adding a third transition hole in the carb."
__________________________________________
Doug please explain, I've never heard of that.

Also can anyone give their personal experiences on the IDF's on a Cleveland?

Is the Cain manifold a magnesium or aluminum? Looks like pickled mag...sort of like the McKay magnesium manifold I ran on the SBC. I personally wouldn't want a magnesium manifold on a street driven car. I had to drain the cooling system every time the car sat for more than a day because the magnesium corroded so quickly. A deal killer for a street car driven on a regular basis.

Also, will the IDF's WITH an air cleaner fit under the deck lid?


The IDF is being touted as a street carb vs the IDA, a racing carb.

If you catch the comments about the IDF, "it has a mid-range circuit".

One of the idiosyncrasies of the IDA is that on an IR manifold on a V8, there is an rpm range, observed on most cars to be about a 400rpm spot, between 2,500 rpms and 3,200 rpms where the engine becomes unresponsive to throttle input, i.e., a flat spot.

I do not know if the transition flat spot exists if the carb is used on a common plenum manifold. It may be a IR manifold issue. Don't know.

This is caused by the design of the carb itself.
It has a hole in the throttle bore, below the throttle butterfly through which the idle adjustment screw projects. It has another just above the throttle plate at idle position.

This is usually called the idle transfer slot in other carbs like the Holley. On the IDA, it isn't a slot, it's these two holes.

Now, cut me some slack on this because I am doing this from memory, ok?

I believe there are two holes in there. The access to them is through the slotted brass screw under the idle adjustment screw.

I believe there are two holes, one like I said for the idle screw needle, another above it maybe at 3/16" higher, above the throttle plate and at the notch in the plate.

That distance between the two is the significant part to this transition between idle/part throttle and main fuel system.

That distance also coincides with the "transition flat spot" of the mentioned rpm spread above.

In attempting to eliminate or reduce the flat spot, some "tuners" have added a third hole, in between those two existing.

This lets the idle circuit continue to a higher rpm range overlapping the main circuit kick in.

Now I personally think that because these are hole and not slots (like in a Holley) you can not entirely eliminate the flat spot with it, but you certainly can reduce it.

I do not have this modification on my carbs. Some days my flat spot is there, some days it isn't. That does have to do with a lot of things including the size of the chokes, and most importantly, the WEATHER. Clean, dry low humidity air accentuates the flat spot. More humidity tranquilizes it some.

IDA's change with the weather, like it or not.

The bigger the chokes, the more consistent the flat spot seems to be there...seemingly.

This is probably one of the modifications Inglese will do on a carb that he knows will be used on the street. An IDA that is. The IDF doesn't need it.

As far as the IDF's being shorter, along with the manifold, I will say this, the IR systems are sensitive to ram tuning length. The longer the better.

Have you ever seen the long ram tubes on the IDA's? What do you think they are there for?
The longer they are, the more torque they add, and it is noticeable.

Like I said, I haven't worked with the IDF's, but the entire ram length to the valve is noticeably shorter then the IDA.

I'd bet you a nickle that adds to loss of drive ability of the IDF's? Again, IR carb systems are VERY, VERY SENSITIVE to induction length.

You may be attempting to reinvent the wheel with the IDF's?

Nothing naturally aspirated (carbs)seem to run with IDA's flat out. Maybe the IDF's come close, I don't know?

That's my explanation Tom. Best I can do. Hope it makes sense to you and helps?
Last edited by panteradoug
i tryed IDA48's on a track-Porsche 928 for the fun... all custom build , all for nothing... jetting became a nightmare Eeker quit the idea , perhaps ever again when i have tooo much time Big Grin

no, besides the looks , i wouldn't try it again , sure not on a sub-"daily" Pantera ! i even wonder , IF you can get it right, what difference you CAN feel in a street driven car....???? perhaps at WOT ... 2% a year ? giving up some torque , using the other 98 % of the year ?
but yeah, i DO love the looks ... Cool
quote:
Originally posted by Kid:
There is a short movie of that 928 on Youtube, correct?

I bought a 40 year old car, partly because of the looks, and don't mind the old thing has some "issues", so why not IDA's Big Grin


I actually feel the same way. I feel the modifications should be period correct and I actually use the Gp4's as a target/role model. Wink

Actually on the tuning, Webers being "off tune" is actually a misnomer or an axie moron. If the are off, the car won't move out of the driveway.

What the issue is, is maximizing them for that day, just like you were racing. What ever the setting turns out to be, is the best the car will run on that day, and you leave it alone.

My setting is 140f/160a, F5 mains. .67f idle on the stock 110 idle air holder. The chokes are 40.5mm, which were custom milled down out of 3/16" thick wall aluminum tubing.

I will tell you that it will also run better on 170f/190a, and F7's seem to run as well as the f5's. The car will pull very, very, very hard on that setting and I actually like the color of the plugs better with it then the 140f combination.

Idle set screws are about 5/8ths of a turn out from the seat.

When the transition flat spot is there it is at 2800 to just under 3000 rpm.

I haven't got the courage to try the third hole yet. The problem is if it screws up the carbs, you have to solder the hole back up.

The IDA's have gotten a little pricey to screw around with them.

Here it is. You can see the third hole clearly in this picture. There are those that swear by it.

Here's a discussion about it from Club
Cobra.
http://www.clubcobra.com/forum...ransition-ports.html

This is the article the picture below is from.

http://www.aircooled.net/rebui...-ida-vw-carburetors/

The new third hole is the top one. The article states that the "newer" IDAs come with the three holes.

Anyone here have maybe the made in Spain 48IDAs of which they can check on?

Some have questioned if the third hole makes the idle heavier.

Apparently no, and because the venturi effect only draws fuel out of one hole at a time as it aligns with the throttle plate. The throttle plate moves in relationship to each hole as you operate the throttle.

It makes a lot of sense to add the third higher hole since it is "higher" in the rpm cycle that the idle circuit stops functioning and the dead spot occurs.

To make it operate at a higher rpm, it needs a higher transition hole. Seems ridiculously simple, but carbs are not rocket science.

This "tune ability" or flexibility is why many say the IDA is the carb to run even on the street.

It isn't just the V8s that see this transition issue. Virtually every engine the IDAs are used on exhibits the transition issue.

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Last edited by panteradoug
I bought a set of Webers long time ago for mine. They were purple which wasn't going to do. I have been tearing them down and rebuilding them which is good. I don't believe they have ever been used but they needed cleaned up. hings like bearings not moving well, dry gaskets, etc.

I drilled the 3rd hole and tapped it for a plug. I have been sandblasting and powder coating the carbs.

The Hall intake for the 400 needed spacers which I was not going to do. I started building my own intake but time got the better of me. I cut the Hall intake in half instead.

I did find the Hall intake put the carbs a little too close together. Linkage had to be slightly bent not to bind and the fuel rail barely went on with a little pushing.

I'll be laser cutting a plate to go in between for linkage.

What fuel pump do you guys prefer? Do you have a minimum size fuel line?

I am going to put in an O2 but the best spot or me is right against the head. I need to see if the O2 can be that close; I am not sure it can.













I like it. Nice solution. My Doug Nash intake was just like that with a plate underneath.

I don't find issue with the linkage on the Pantera. I did run that set up on my 68 Shelby when I had the Boss351 in it and I did have linkage issues there.

The simplest solution on it was to the linkage was to use Inglese's adapter kit to have the carbs parallel rather then opposed. The throttle input also had to be put on the drivers side of the manifold and the pedestal was useless.

theoretically the Hall manifold is correct with carb orientation because of line of sight to the valve. Does it really matter? Probably not much.

For the Pantera, the pedestal works perfectly for me.

I had binding initially with it on the Pantera but moved the left to right bank connection to the rear. That made a very simple linkage connection at all points.

So what's wrong with purple? Big Grin

I use a Holley electric fuel pump and find -6 hose are fine. 3 psi max. You do not need high pressure with these things. That is Holley think.

I don't use those fuel rails. Those are the ones made by ISP in Colorado. I use 3/8 ss tubing with tubing nuts and the Earls Weber T fittings. I like the sorta retro/techo look and they make great handles for hauling the manifold around.

How much off center are the fuel holes on the rails? 30 thousands? Gotta leave the carbs loose, align the rails, then tighten the carbs I would think...not like you wouldn't already know that?

Check out Jay Cee web page for the Weber parts you need.

http://www.jayceevw.com

The bearings are sealed. There should be no way the throttles should bind. White lithium grease here and there is all that you need.

The real question to me at the moment with Webers is the camshaft.

You need to remember that these things were run with race duration cams and overlap that blew the fuel out like a geiser.

I can tell you that my heads need lift to work. The "Weber" cam with 586 lift and hydraulic lifters isn't going to cut it for my heads. Try 6 something.

That is the part that is unresolved for me.

I still feel that using the Weber cams gives away 100hp needlessly. This is the part of the race vs. street that I may never be able to resolve?
I am afraid I did not consider the webers when I built the engine. I figure at this point it is what it is. The engine was built as a low rpm torquer engine. My goal was very good tq limiting rpm to 5500rm. By doing so I figured I can get by with much less valve spring problems. We dynoed it with a Deamon on a CHI intake right at 500hp with 534lbs tq. The engine had 434lbs of tq at 2000rpm and the dyno could not start any lower with he tq. I can also tell you the exhaust primaries on the dyno were pretty small.



Cam is crane 529721
276/284 seat to seat
214/222 .050
.562/.586 lift
111 center

If I ever get caught up I have another 400 I want to go hog wild on. We have a draq strip a couple miles from my house. I have an old nascar I want to use as a rolling dyno and would like to play use that to set up another motor. We'll see if it happens. Life is pretty damn busy right now.
How close do you think I can mount the O2 to the head? I have completely different type of headers with all 4 primaries going to the back. The primaries land in a common muffler far down the line.

I am afraid if I put it in the muffler section it will be too far away and not heat up adequately. Since they need to be mounted at least partially upward, this limits my location to the top of the runners here. My concern is that the O2 sensor does not get too hot:








In the headers I made for the MG I run them about a foot off the head. You can see the port on the right side of the right header here:


quote:
How close do you think I can mount the O2 to the head? I have completely different type of headers with all 4 primaries going to the back. The primaries land in a common muffler far down the line.

I am afraid if I put it in the muffler section it will be too far away and not heat up adequately. Since they need to be mounted at least partially upward, this limits my location to the top of the runners here. My concern is that the O2 sensor does not get too hot:


I have O2 sensors as close as 5 inches to the heads and they work fine there. I also have an O2 sensor mounted right before the muffler. It also works fine there. Since most O2 sensors have a heating element built into them I do not think mounting them far down the line would be a problem. However, if they are being used to control engine management (as opposed to just a air/fuel ratio gauge), I was told they need to be as close to the engine as practical...
I would think in the collectors is a good compromise. That's where mine is. Would you want to read just one cylinder?

Most current cars would have two locations. First as close to the engine as will fit which means right after the headers but before the pre-cat and the second after the cat.

The closer to the engine that you go, the shorter the lifespan of the sensor.

Of course those locations are for different reasons than yours.
Last edited by panteradoug
So guys, if you run IDF's and air cleaners, are you going to have a fire? I'm sure it has to do partly with the cam selection. I read an old post from Dave (Whiplash) that said he took his air cleaners off after having two air cleaner fires. Not having air cleaners seems like it would shorten the engine life.

Are you going to have engine popping when decelerating with webers, or can that be tuned out?

Do elevation changes make huge drivability issues?


I have been thinking about this topic for a week or so, and here's another thought with that Cain manifold: Run TWM/Borla IDF throttle bodies and EZ EFI... In other words, run IR fuel injection under the decklid in a different way than the common Hall Manifold/IPSCO throttle bodies or Kirby manifold/IPSCO throttle bodies.
http://www.youtube.com/watch?v=JRdwWgSGqvc

Watch the top of the carbs in this video. Do you see the fuel mist coming out of the stacks?

That is the reversion caused by the overlap on the camshaft.

This video has a better side view of the reversion.

http://www.youtube.com/watch?v=caGWuuXqZq4



It doesn't matter what carbs you use, it is the effect of an individual runner intake manifold that has no common plenum.

The Trans-Am Boss 302 with the dual Dominators does it, so does a Doug Nash with dual Autolite inlines.

If you put any kind of an air cleaner fabric over the stacks the fabric will be saturated not just by fuel, by atomized fuel.

The ONLY way with carbs not to have issue is run no fabric over them at all AND/OR use a camshaft that has something like 28-30 total degrees of overlap. That reduces the reversion to almost non-existant.

If you look at cam specs, that is very close to the stock 351-c Cobra-jet cam these engines came with new from Ford.



There are two 351c cam profiles I know of that are refered to as "Weber Cams". The one sold by "Inglese" is the Comp Cams version. Hydralic lifters, .586 lift, yada-yada-yada. The other is by Cam Techniques and is the virtually the same.

Look at the power numbers and the flow rates of the heads on these engines. You will notice that the engines start to make 500hp + with over 600 lift. Heads start flowing over 300cfm over 600.

The "Weber Cams" only start to approach this lift. The CJ cam isn't even 500 lift. It is 480 something.



Whiplash I think, is talking about the comp car he has? The factory comp cars ran 48IDAs. Holman-Moody solid roller lifter camshafts and were the same as the 4v Bud Moore race engines with his special "race plenum" intake manifold. (Ram boxes for lack of a better, or correct term).

The GT40 Mark I's ran 48IDAs Webers and the T/A Boss 302s, ran the dual Dominators on an IR intake "XE" manifold, have air chambers over them on which the mist accumulates like early morning due on the grass. All run with regular big overlap race cams. The 289 "LeMans cam" has 82 degrees of overlap. No special Weber cut cam there.

You need to keep the mist away from the headers and run no stack covers and you are generally ok with fire risk. I can tell you that you smell the gas when you come back off of the track OR back to idling with no motion after a flat out run.



The engine itself is going to have a shorter life span because of the cylinder washing from the volume of fuel being "dumped" into the engine. It doesn't matter if it is IDAs or IDFs. The end result will be the same.

Regardless of how clean you can get the carbs to idle and run, every time you mash the throttle, or even just move it, you have eight accelerator pumps jets doing their thing and the instantaneous black smoke from the exhaust is noticeable.

Interestingly enough, not many talk about the pump jets while tuning these carbs. I found that I could almost eliminate the pump shot (.050 vs stock .100) with no noticeable effect EXCEPT it made the cold engine very difficult to start without them.

The oil rings do not like it and you will build up a black film in the exhaust which is the engine oil you are washing out of the engine. It's the accelerator pumps doing the cylinder washing.

THEORETICALLY, you could reduce 7 of the pump jets to minimal except for 1 and use that one to start the cold engine...THEORETICALLY. I don't know how practical that actually is though. The engine is VERY easy to flood trying to start it cold if it doesn't fire up on the first crack of the key.

In addition, the air filters just make the engine harder to tune right and if you are going to do open track days then you take the filters off.

However, I do that even with the dual Holleys which seemingly adds 100hp to the engine at WOT.



The only way to avoid most of these issues is to run IR EFI, as you mentioned. Then that's an entirely different animal, but they still will like to run around naked with no tops. Why not? I like to encourage that behavior as much as possible too?

The IDFs don't fix any of these issues. Most of the issues are created by using carburetors on an IR (independent runner) manifold. The IDFs just have a different idle system. Are you SURE they fit UNDER THE SCREEN? The front of the screen is very low.



Consider this...even if they fit.

Rule of thumb on any carb is you need a MINIMUM clearance over the top of the intake stack that is approximately equal to the OD of that stack, i.e., 48mm, 1.89". This includes air cleaners. Many of the air cleaners offered, simply stated are built WRONG for these carbs. Maybe they belong on your leaf blower but not on a Weber with velocity stacks.

The IDAs were run by some of the biggest race teams ever assembled, and some of the most successful too. There is a reason they were used, and there is method to the way they were applied. Think you are smarter then Fords GT40 program with unlimited budget? Really?

Want to duke it out with Phil Remington? Go ahead. Be my guest. I know better.



IDA's always pop at deceleration, not bad, but a sure characteristic that you are running IDAs. I would PRESUME the IDF's do also?



Running "Webers" is hardass. There is no way to pussyfoot around them. A love/hate relationship with Malaria type re-occurrances and Lord knows, psychotic masochistic undertones? But then again, you would probably only know this all from experience, are hopelessly addicted and understand that having the ultimate doesn't stop the desire for more. Frankly, it just never ends.

Oh..."your mileage may vary". Big Grin
Last edited by panteradoug
quote:
Originally posted by PanteraDoug:
What are you doing for a roll bar? Is it in the engine compartment?


I wanted to bring it into the engine compartment but I could not figure out how to make it removable. I wanted it removable if for no other reason the paint process.

I did mount it in the cab but it comes through the back ties into the roof at the decklid hinge then comes back into the wells. The wells are reinforced with a plate then a built a ladder bar:

http://www.rc-tech.net/pantera1/rollbar/roll.htm


http://www.rc-tech.net/pantera1/ladder/lad.htm
1)Thank you for the compliment but I post it to try to illustrate what someone is getting into with these 8 stack IDA setups.

2)I had Halls 3 point roll bar in the cabin and got tired of just catching my left hip on it getting into and out of the car. Sold it to LastPushbutton, Bill Gaino. He loves it.

It didn't really occur to me that the profile on either side of the firewall bulkhead was the same in the cabin or in the engine compartment until too late.

I invision being able to cut that bar into left and right halves, welding flanges to it and bolting it to the roof as well. This would let me have my cake and eat it too since I could run the rearward braces as well.

Why can't that all bolt together?

Gary Hall had cautioned me that the gas tank would need to be "slightly modified" to clear the bar. He had built a bar for "Purple Passion" to stiffen the chassis when he turned it into a T top. It shows in one of the Hall Pantera color catalogs but apparently it is the only bar ever built and the fabricator, Bob at Precision Proformance, refuses to build one. Sounds like a tough job?

When I asked Bob at Precision Proformance about it, he said the tank would need a lot of modification to do that.

Why not tie that together with doing a new stainless tank is what I thought?

Anyway, thanks for the links on your bar fabrication. Looks like you have a lot of fun with that? I want minimal fabrication chores to do these days. I've had too many years of having cars apart on a "two week" project? Wink

Vacuum. Interestingly enough, my manifold came with a 3/8 pipe port drilled and threaded into the #8 intake runner.

This is for the vacuum line for the brakes. It makes enough vacuum to operate them.

I've been thinking lately of plumbing the runners together for a vacuum gauge. I think I want to put carb spacers in and plumb the fittings to them? Maybe 1/16npt to keep it minimal OR maybe press in 1/8" steel tubing like a carb would have in it's base for vacuum connections?

Whether or not those -3 lines provide enough vacuum is going to be trial and error. If not, like you said, you can always try a vacuum reservoir hidden somewhere on the firewall?
Last edited by panteradoug
Thanks for the info on the vacuum; that's helpful. You know on my MGB (GM V6) I put the 02 and vacuum gauge behind the radio delete plate which is held in by super magnets. Tuning the car with 02 has been fantastic:






As far as the roll bar behind the firewall I think if you broke it up you could make it removable but I took the main hoop and spent the afternoon trying to snake it in. I was never able to get it in. If you do let me know I would like to see how you do it.

As far as the gas tank, did you see my headers?

Stock tank wouldn't come close. This is the tank design I am working with. I am just waiting my turn at the laser to cut the aluminum. We were down for a week and a half due to a lightning strike and personal projects are on the back burner right now.


I wish I could fix it that easy. This exhaust is radically different.







I am also moving the tank to the right side of the car and putting an oil cooler on the left. I don't like oil lines running under the car. I am ducting the air through the side vent with a fan.

You can see how the primaries shoot out and the aluminum on the left inside which will duct the air through for the oil cooler:


quote:
Originally posted by Corey Price:

So guys, if you run IDF's and air cleaners, are you going to have a fire? I'm sure it has to do partly with the cam selection. I read an old post from Dave (Whiplash) that said he took his air cleaners off after having two air cleaner fires. Not having air cleaners seems like it would shorten the engine life.



Corey

I know you're capable of researching the internet ... and that's what I encourage you to do.

If a person's only exposure to the world of Weber carburetors is the IDA, then it has only scratched the surface, and not the best surface either. Weber carburetion is popular world wide on smaller engines, both with plenums and with individual runners. The american V8 muscle car crowd are the only hobbyists that adore the IDA carburetors, its actuallly a small market for Weber. As they were originally designed they are a racing carburetor for a motor that is either accelerating at WFO or braking. I'm sure there are guys who can modify them to work better ... if that's where your head is at.

The IDF's are used in many more applications than the IDAs; like the DCOE, the IDF is a very popular twin throat racing & high performance carburetor. It has been used as oem equipment in a few limited production vehicles, including a Ford Escort (the European Ford Escort RS2000 Group 1 cars). And it is accepted by very many sports car hobbyists as an acceptible replacement for various Delorto and Solex carburetors. It is also sold by Pegasus Racing due to the demand for the carburetor. IDF Webers are offered in 40, 44 and 48 mm bore sizes. The main, idle, air correction and accelerator pump jets, the emulsion tubes and venturis, are interchangeable. It has a float design that makes it very popular for off-road applications, a vacuum advance port, and four progression holes for smooth light-accelerator response. The differences between the IDA and the IDF, like the additional transfer circuit, add up to make a big difference in performance. You can bet the IDF would not have been selected for oem applications if it's calibration were as easily upset as the calibration of the IDA is reported to be.

Individual runner carburetion has been used on many production automobiles and motorcycles ... AND Every Single Cylinder Internal Combustion Engine Ever Made ... think lawn mowers, leaf blowers, chain saws, generators, etc. They don't have problems with altitude and fires. So continue your search on the internet, you'll find the answers you seek. I'll tell you what I know. Inglese uses wide lobe separation (115 degrees) for the cams he sells for IR. So one can assume from that bit of info that overlap is the source for some of the problems with IR systems. I have helped a couple of guys install IR weber systems in my past; one was an IDF system on a Ford Fairlane (Windsor) V8 ... the owner was happy with the results. Another guy chose an IDA system for his SBC, he was unhappy with the results, so he eventually sold off the IDA system, purchased an IDF system, and has been using it for over 20 years.

Pictured below is an IDF system fitting under the engine screen of a Pantera

-G

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  • weber_IDF
Last edited by George P
quote:
Originally posted by Kid:
If you want/need vacuum only for the brakes, you could consider to run an electric vacuum pump in the front, instead of the hassle of working with a line from the back to front. Some modern cars (electric and non electric), do run those little electric vacuum pumps.


I considered an electric long time ago but I already have added many electric items; electric power steering pump, trans cooler pump, fans, etc. I like the simplicity of a vacuum line if it works ok. I can always change it if it doesn't.
Doug,

So I think you're trying to say that the cams that work best with Webers are lower lift and less duration (and overlap). Your post is misleading- do the "Weber cams" have .586" lift, or do they have .5" lift? Are you saying that a street-able Weber-compatible cam would make it difficult to make 500 hp without tons of reversion? Is this the cam you're talking about- http://www.compperformancegrou...e=FordWeberCamshafts


George,

I have been searching, but probably not in the right places. I'll look some more.


If you could build a IR EFI system that would fit under the decklid with off-the-shelf parts & no significant fabrication, modification of existing manifolds for injector bungs, etc, wouldn't that be cool? I think we have that here in addition to the Weber IDF idea. Yes, there will be some fab work on a center bell crank and linkage, but I'm sure that it isn't anything new or super difficult. The Cain manifold has a tower for the bell crank in the center.
That is the "Inglese" "351c Weber Cam" (CompCams). The CamTechniques is as I recall, .586 lift. That cam I saw run on the track with this setup. In my opinion, the car was way down on power. It didn't even sound right and have that howl you hear from a distance?

But...first off Corey, you have to define the term "BETTER"? Everyone will have a different interpretation of the term. That's where it gets a little sticky (controversial).

The IDAs offer the possibility of this duality, in that they can be "tuned", as in tuned down to make them more livable as a mostly street driven induction system, OR they can be tuned to run them flat out as was done in the 60s and 70s as the ultimate (for the era) naturally aspirated induction system.

The carbs themselves are easily changeable, relatively speaking, from day to day because of the top access to the jetting.

The camshaft of the engine is not.

It is up to the owner to decide the nature of the engine.



To me, it is difficult to live with them on a daily basis with a big overlap cam like those run on the race cars. Being a Walter Mitty type I suppose, that's what I really want though. Dam the practicality?

By the same token, the nature of this setup of constantly wanting more out of them makes running the "Weber Cams" somewhat of a bear trap.

Those cams are simply de-tuned to eliminate the reversion of the fuel.



As with any cam selection, you really have to try both of what you are considering. You can only get a cam recommendation from a cam company. It's up to you to decide which and it is a lot of work to try various cam profiles...but that's the gig?



For the amount of usage I give the car, running the carbs with the open stacks and the big overlap is ok with me. I'm not crazy about all that fuel being blown back, but knowing the alternatives I can accept that fait.

When you select a camshaft, you match it to the flow characteristics of the heads do you not?

If you are making your maximum power at say .650 lift, why would you put in a cam that is .571 or .586?



The simple thing in the end I think is not to get invested into Weber carbs in the first place. The better alternative now is to use the Classic Fuel injection which looks just like them. Then all of this debate on which door to choose, the Lady or the Tiger becomes purely academia.

Problem solved...no more reversion. No fuel in the bowls to be reverse flowed because now there are no fuel bowls?

Everything computer designed, matched, and optimized from the beginning. Then you just tune the setup with your laptop. "Hands on" ultimately is sooo over rated...right?
Last edited by panteradoug
Tom that is an up-loaded picture, not a linked picture. You have to be logged-in to see the picture, if a person is not logged-in they see the red circle.

Corey the IDF is popular with VW (dune buggy) and classic Porsche owners. I believe its the carb of choice for the poeple who race the 1.6 liter in line Fords too. Check out various other small sports car groups like Fiat, Alfa, Lancia. A forum for rally racing will probably have info too.

I hope everyone understands I'm not trying to step on any toes, I respect you guys who love your IDA Webers. But Corey's original post asked for IDF information, and there is not a lot of experience with them among our members. So I made the suggestion for him to look elsewhere, because I know that carburetor is actually very popular in other areas of motorsport.

-G
I have posted this in a similar thread some time ago.
But here it is again.
A different take on the Weber look, using injection.
My Pantera runs fuel injection, 8 x 48mm throttle bodies.
Similar set up to Weber’s & a similar look.
This is an old “Pantera Performance center” kit I found on Ebay.
I assume from the 1980’s.

Velocity stacks I custom made, they are in two pieces where the top screws on to clamp in place a stainless mesh screen.
I have run the car with & without the screens on the Dyno & it made zero difference to the tune or power output.
Not that was easily noticeable anyway.
Computer is a Motec with crank angle sensor, TPS & MAP sensors only.
I rebuilt the throttle bodies & re-set the butterfly clearances.
Runs really nice, easy to start & reliable.
Combined with the 11:1 CHI 4V heads it made more responsive & snappier power.

I don’t run the car in the rain, nor do I wash the car with water.

The only issues I have had is balancing the throttle bodies to make sure they are all breathing the same amount at idle.
Also, because of the high air flow of 8 x 48mm butterflies it requires a corresponding amount of fuel when snapping the throttle open from idle.
So running rich at idle was causing the spark plugs to foul.
Re-tuning the car at idle & leaning off the fuel didn’t work, it simply backfired.
So now I have changed the Spark plugs from NGK BCP6ES to a hotter BCP5ES.
Yet to try it & see if it has cured the plug fouling problem.

The other issue is that each throttle body has its own return spring. And they certainly are required to get the butterflies to snap closed.
But combine the tension of 4 x springs & it makes a very stiff throttle pedal.
So at some stage I’m going to have to look at a progressive throttle linkage to gain some more leverage & better throttle control.

In regards to Vacuum.
I run an 8” dual diaphragm booster as my master cylinder is 1 1/8” bore, (4 piston rear calipers).
I also run a vacuum bottle up front with an extra check valve.
I tried supplying vacuum from one port & it was no where near enough.
So tried 2 ports, still not enough.
Then went to four ports & that was sufficient.

regards,
Tony.

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  • Engine_copy
That's a very early system. Generally you need three inputs to make the program work. Oxygen sensor, TPS, MAP.

There is the identical set up here on a wide fender car Dennis did and the car runs like do-do because it lacks an oxygen sensor. Glad yours works ok.

Last I heard about the car here is it was being "revised" to include more inputs.
quote:
Originally posted by PanteraDoug: That's a very early system. Generally you need three inputs to make the program work. Oxygen sensor, TPS, MAP.

That would be a pretty crude set of inputs by today’s standards. However, some have achieved good results running IR EFI set ups with scheme’s as simple as just Alfa-N +RPM if the owners put the time into tuning under both controlled and road circumstances. If you have stable altitude and atmospheric conditions it can be sufficient but sort of depends on your engine specs, driving, and expectations. A big cam and a lot putting around town driving will require more effort to produce more civil street manners, but IR with good ECU and additional sensor schemes can be uniquely suited to do so. In closed loop most find that that O2 sensors aren’t very useful for much more than trimming idle and cruise, even with wideband O2 sensors. They are of course essential when it comes to emissions control if that is important to you. Things change too rapidly for closed loop O2 control to be very useful across the entire rpm range as far as performance goes for most street tuners. The race team’s set ups are much more sophisticated and can be a totally different story in this regard. I think wide band O2 is certainly useful input for tuning but position in the exhaust circuit and leaks can often create transient responses and false readings. For street driven IR, I’d recommend TPS, MAP, RPM, Inlet air Temp, Engine/Coolant temp, wide band O2, and maybe Idle Air Control (IAC), depending upon your control scheme. I’d also recommend that you run a crank trigger and gain full control of your ignition maps while you’re at it; why not have any advance curve for any set of conditions? Many of the modern ECUs have excellent subroutines that give you a great head start on schemes for idle, cold start/warm up, off-idle and enrichment schemes, etc. A lot of sensors and full control or fuel and ignitions MAPS means great potential for tuning but will also mean a lot of tuning to achieve the results. Be prepared to invest the time. Most find they can get to acceptable results fairly quickly and then just evolve and refine their schemes over time.
quote:
There is the identical set up here on a wide fender car Dennis did and the car runs like do-do because it lacks an oxygen sensor. Glad yours works ok. Last I heard about the car here is it was being "revised" to include more inputs.

I’d say it’s either poorly sensored/equipped and/or tuned but the O2 sensor is probably the least of the issue if that is the case.

Best,
K
quote:
Originally posted by Edge: My Pantera runs fuel injection, 8 x 48mm throttle bodies.
Similar set up to Weber’s & a similar look. This is an old “Pantera Performance center” kit I found on Ebay.

I followed your build Tony and must compliment you on executing it very well. It’s very nicely done.
quote:
I assume from the 1980’s.

Probably at least mid 90s or more recent. If it has TWM throttle bodies without the “Oldham” couplings, I believe Garry Polled implemented those about 10 years ago. He installed those between the barrels on his IDA throttle bodies because he said in instances where there was big temperature rise, the thermally enduced growth would cause binding due to the difference in linear thermal expansion between the steel shaft and aluminum TB. I have never had that issue (at least between barrels), and think this is more likely attributable to deformation of the intake manifold while mounting with the throttle bodies already mounted. This binding was a common problem on the older Hilborn, Enderle, Falconner, etc. and like units with a single shaft spanning all four barrels. Now, the connection between the two TB shafts on each bank on a set up such as yours is a totally different story.
quote:
Velocity stacks I custom made, they are in two pieces where the top screws on to clamp in place a stainless mesh screen.

Those are very nicely done.
quote:
Computer is a Motec with crank angle sensor, TPS & MAP sensors only. I rebuilt the throttle bodies & re-set the butterfly clearances. Runs really nice, easy to start & reliable. Combined with the 11:1 CHI 4V heads it made more responsive & snappier power.

That’s pretty Spartan as far as sensors go. I would think you would want to add several temp sensors for inlet air and coolant/engine temp. When you say MAP, are you trying to run a speed density scheme such as employed on a 4-Barrel by using a plenum plumbed to each barrel of your IR set up? Or just using it as atmospheric pressure correction? When you mention crank angle sensor, are you able to actively manage your ignition maps as well? As I mentioned in the earlier thread, the rest of the sensors such as O2, idle air valve, are really just for idle, warm up enrichment schemes, and leaning at cruise.
quote:
The only issues I have had is balancing the throttle bodies to make sure they are all breathing the same amount at idle. Also, because of the high air flow of 8 x 48mm butterflies it requires a corresponding amount of fuel when snapping the throttle open from idle. So running rich at idle was causing the spark plugs to foul. Re-tuning the car at idle & leaning off the fuel didn’t work, it simply backfired. So now I have changed the Spark plugs from NGK BCP6ES to a hotter BCP5ES. Yet to try it & see if it has cured the plug fouling problem.

This is where you might benefit from some additional sensor input. Many of the aftermarket ECUs now have many algorithms and subroutines for cold start, off idle enrichment, warm up, idle control, that are very useful and user friendly. Not sure what Motec ECU you’re running. I’m not very familiar with them but in the past have known them for their high end racing stuff. Many people have had very good results plumbing a vacuum line from each runner to a plenum and using an IAC and closed loop O2 to regulate idle. Those doing so on plenums that also run their MAP sensor may find some problems caused by the IAC altering the MAP signal. Some isolate the two plenums. IT should be noted that these plenums can be sized and remotely mounted.
quote:
The other issue is that each throttle body has its own return spring. And they certainly are required to get the butterflies to snap closed. But combine the tension of 4 x springs & it makes a very stiff throttle pedal.

I’d recommend you either put lighter springs in each TB or as you mention, consider different linkage. A spring on each TB is a good safety measure.
quote:
So at some stage I’m going to have to look at a progressive throttle linkage to gain some more leverage & better throttle control.

I’ve fiddled with a bunch of schemes and for the last ten years have always used the one pictured on the IR system below. I use this scheme on all my IR set ups from EFI, to Weber IDAs, and Inline Autolites. The throttle plates in each bank counter rotate to promote flow symmetry. The spring loaded balance bar linkage in the center between the TBs are very important. The ones pictured are a Kinsler product but the allows for axial growth and misalignment between TBs without binding. The cable actuated wheel is important feature of the linkage. In the initial position, the link arms are set close to center so that it takes much more rotation of the wheel in the early movement to produce the same change in angular position of the throttle plates. This gives good resolution with the accelerator pedal. It then get’s gained up progressively as you put your foot into it. The cable actuated wheel also has one subtle advantage over typical bell cranks schemes; you can calculate the diameter of the wheel for the exact amount of pedal/cable stroke for a given degree of rotation. The other thing is the mechanical advantage of the wheel on your linkage is always the same because the cable pulling force is always applied at a point the makes the applied lever arm half the wheel diameter. I mount the wheels in ball bearings and the linkage feels very nice. High quality linkage is very important for IR for performance, safety, and reliability to stay in tune.


These set ups will fit under a Pantera deck lid with 2" tall filter elements without notching the lid.
quote:
In regards to Vacuum. I run an 8” dual diaphragm booster as my master cylinder is 1 1/8” bore, (4 piston rear calipers). I also run a vacuum bottle up front with an extra check valve. I tried supplying vacuum from one port & it was no where near enough. So tried 2 ports, still not enough. Then went to four ports & that was sufficient.

Mixing your comfort accessories with performance is like mixing business with pleasure. I’d recommend running a vacuum pump and separate plenum and circuit for your brake booster and call it a day.

Take care,
Kelly
The system does include coolant temp & RPM.
When we made the new exhaust system we fitted a socket for the O2 sensor.
This was plugged in during the dyno runs to get the correct fuel/air ratio, but the Motec does not use it.
The MAP feeds off of a vacuum port on each throttle body.
I’m pretty sure it’s for atmospheric pressure correction.
The Motec has provision for more sensors & given more time in the future it will be expanded upon to refine the tune.
Inlet air temp sensor is possible, could be fitted above the velocity stacks, or in the side of one.
I also have a cam angle sensor which plugs in where the Distributor was, not set up yet.
There is a spring loaded connection between each throttle body that has a screw adjustment for synchronizing.
I’m not right up on the tuning of this system & I need to learn a lot more.
It’s been a steep learning curve.
I have simply done all of the mechanical side & the manufacture of components etc.
I have a friend who does the electrical & another who has tuned on the Dyno.
So I rely heavily on them for tuning input.
Kelly, your comments here are most helpful, the more information the better.
I like the Kinsler throttle wheel that would give a nice progressive feel.
I did consider a vacuum pump but was trying to get it right using manifold vacuum & reduce the number of electrical accessories.
I may need to chase down an OEM type vacuum pump from a modern car.
We are machining up new rims right now, (17x9.5” front & 19x13” rear).
I have some 8 piston Brembos to put on the front; they tuck nicely in the 17” rims with big Wilwood rotors, so I will need good vacuum supply.

Regards,
Tony.

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We'll let Corey's thread get back on topic one of two ways.

If one of the members wishing to discuss IR EFI wish to start a new thread on that subject I'll gladly move the appropriate posts to that thread, and the off topic conversation can carry-on over in the new thread.

Or we can just let the off topic coversation end, and allow Corey's thread to stay on topic.


-G
I take back the part about the thread getting off-course. The IR EFI stuff is great to augment the Weber IDF stuff.

I've been researching IDF's a little more. I am going to order a few books on tuning. I have also researched IR EFI a little more, as well as the standard 4-bbl carburetor. There are so many choices that it's actually fun to think about!

I sent a message to the company that has the manifolds in Australia. I know there are other people who were looking at this manifold and hoping for a group rate or going in on shipping, but I haven't heard any more about it. I am considering using this and IDF Webers or using 2930 Series TWM throttle bodies for IR EFI. Looks like the manifold has a center post that is probably meant for a bell crank or for the wheel approach...

If I do this, I might spring for some AFD heads as well and see about getting it all shipped together.
I have been looking into IDF's a bit more again for fun.

It turns out there is a local VW shop near where I live (in Salt Lake City) that rebuilds Weber carbs. I talked at length with the guy who rebuilds and tunes Webers, Solex, Zeniths, Delortos, etc. I even compared first-hand IDA and IDF carbs and investigated differences with them both in my hands. If anyone is wondering, the IDF is about 4" tall from bottom to top of carb, not including the main jet extension. IDF's are made to take air filters, have the same jets as IDA's, and have four progression holes instead of the IDA's standard two. While the IDA can have another progression hole drilled, (the so-called "intermediate circuit") the IDF is the true street carb according to the rebuilder/tuner. The rebuilder/tuner seemed to like the Delorto carb that has the same mounting pattern as the IDF, but said that they are no longer being made and scrounging up four 48mm versions all the same would be much more expensive than four brand-new IDF's.

Four 48 IDF's are actually cheaper than four 48 IDA's...
It isn't just the height of the carb, you need 48mm clearance over the top of the velocity stack clearance to the deck for proper flow.

The IDA is about 7" to the top of the velocity stack but I think the main advantage of the IDF is that the manifold is lower then the IDA's.

You can run the IDA's with a shortened velocity stack and auxiliary venturi like the Cobra Daytona Coupes did. You can get them down to about 6".

I've done this and it doesn't seem to effect the performance of the carb at all.

I would also say that you can come as close as about 1-1/2" clearance to the decklid.

You could shorten the IDA, cut our the reinforcing to the decklid and probably clear without cutting through the skin.
Doug, you might have missed the point of the IDF discussion. Hope this helps:

quote:
Originally posted by PanteraDoug:
It isn't just the height of the carb, you need 48mm clearance over the top of the velocity stack clearance to the deck for proper flow.


IDA's need velocity stacks to help the venturi work properly as the guy at the shop I visited said. IDF carbs do not have the same venturi design and should not need velocity stacks. IDF carbs were made to readily accept air cleaners due to the flat top plate. To get an IDA to accept an air filter, you have to use a velocity stack extension and modify it. Please google a Weber IDF and compare the image with your IDA's. They are different carburetors. If you needed the velocity stack, a standard 4-barrel carb would need it too, right? Yes, the velocity stacks create a nice transition for the air to go into the carb to reduce loss of flow, but I would be surprised to see it make a big difference for the street-going average joe with an air cleaner instead of the velocity stack. Give me an air cleaner & better engine longevity any day in trade for a small percentage of power lost.

quote:

The IDA is about 7" to the top of the velocity stack but I think the main advantage of the IDF is that the manifold is lower then the IDA's.


I held both an IDF and an IDA in my hand yesterday. The IDA is around 1" taller than the IDF. The IDF has a flat top plate, whereas the IDA doesn't. The IDF is 4" tall and the manifold is shorter. The advantage to the IDF is actually the short size, ability to run an air filter without stack adapter, more progression holes for better transition from idle to full throttle, and you can run it under the decklid and engine screen without cutting through the decklid and engine screen.

quote:

You can run the IDA's with a shortened velocity stack and auxiliary venturi like the Cobra Daytona Coupes did. You can get them down to about 6".


IDF's will be shorter, even with velocity stacks.
Hum. I don't think I missed the point. They are two different carbs.

Not intending to be argumentative, lecturing etc but the point of multiple carbs on an individual runner manifold is for performance.

Everything about the IDF is a compromise system. Why would I want to compromise with less performance?

Sure they look great. In design there is a school of thought that form follows function. If they work...they are beautiful.

So maybe you're right? I don't get the IDF's? Smiler
Last edited by panteradoug
If you plan to go for a kind of linkage which will connect the carbs of the two sides by means of a rod, then study the movement of your butterflies closely. I can't properly judge the levers used in the 302 set-up your blog links to, but I found out my original set-up made the butterflies of both sides move in an ansynchronous way. They would close at the same time, and reach WOT at the same time, but midway there was a significant difference. The set-up as I originally had it, is in use though by many people using Webers. Apperently nobody notice(d) this...
Cory, love the write up on the Webers and the manifold. Wish you lived closer....I'd love to do the IDF also. That maifold is very nice. Whats the costs? The VW crowd uses the 48IDA's a lot. I have a few friends that have a VW Bug and Carmen Ghia that do 12.20'S and 11.25 in the quarter both using two IDA on 2300cc motors. They've figured out how to make them work.

I'm trying to visualize the routing for the throttle cable to IDA's or IDF's on a Pantera. I had a set of 48 IDA's on a small block chevy that was a right hand drive mid engine CanAm car. The linkage is definitely the the #1 or #2 issue. You can get the IDA's to work on a V8, and they can be made to transition from the low to high circuit pretty well even without the additional transition hole. I will say that I have had no experience with the IDF's but would think that that would be a better way to go based on some of my experience with IDA's..

The linkage on my car came back from the driver (right hand drive) along the right side of the drivers seat, then once past the firewall started to to make a gradual up turn to the outside of the car, then back toward the center of the car and then connected in middle of the front and back IDA on the right side. It was attached with a tripod like mount that connected at the top and bottom of the two IDA's...the cable angle worked well and because of it's location didn't take any fancy bell cranks or other mechanisms....the arms on the IDA's throttle shafts were all the same length and the way the linkage was set up pulled identically on all four carbs. Even with that the linkage was finicky...it tended to need a frequent adjustment to keep all the carbs in sync at idle...once they were there it ran great, but seemed to get out of adjustment often, possibly because there was a decent sized spring to keep eight throttle butterfly's closed and could have been too strong therefore pulling too hard on the linkage which could pull it out of adjustment. It was a stiff pedal, but there is no way around that. I remember distinctly saying to myself I'd love to have a nice four barrel carb to eliminate the constant adjustments. Not sure if there is a way to stop an individual runner carb like this from the need for constant adjustment. By nature with four separate mechanism working on two cylinders each, they all must be spot on to work well at idle and just off idle. Visualize four two cylinder engines working together with the same crankshaft, but separately when they are out of adjustment. Possibly the Pantara throttle cable is a light enough cable that you don't need to have such a strong spring to close the throttles. Mine was a solid cable that was about 3/8" diameter on the outside and required a fair bit of oomph when bent to make it actuate. I've seen these cables used a lot in marine usage for engines and transmissions. A heavy pedal is also not the best thing for gentle throttle modulation in a road car during cornering.
Last edited by tomsealbeach
More to come- stay tuned as I'm working on Part II presently. I have more pictures of a carb I have now and pics of the bare manifold from Brian (72pantera).

Tom, the manifold is a bit steep- $925 AUD. The IDF's are cheaper than IDA's, expect to pay around $400 or a little less per carb. Then you have other parts. I'll go over a lot of this in my blog.

I plan to buy a manifold from Aussiespeed this year and stash it while I finish bodywork.
Last edited by coreyprice
I don't remember the exact price, but I know I got a little bit of a deal from Mark. I think after converting to USD it was about $930USD and he tossed in shipping. Not to bad I guess, 950AUD is just shy of 1000USD currently.

Also, as I'm sure these are not a hot commodity, mine needed to be cast before hand. This took about 4 weeks or so including the machining after. I didn't really mind as I wasn't rushing to drop however many thousand at once on the setup.
Interesting to look at the different complete kits out there...with most there's almost a $2000 markup for 351c setups with IDA or IDF compared to small block chevy setup....can it really cost $1500-2000 more for the manifold for a 351C? This Ausie manifold at $950-1000 seems like a deal, with carbs...I saw new IDF's on ebay for $375. A few of the kits mentioned that the carbs had been modified for low to mid range response.
quote:
Originally posted by 72pantera:
Kid, if I recall correctly, the throttle cable links up to the driver side of the stock autolite carb. About maybe 3-4 inches from the center point of the 351. I would think one would not run into any issues running a cable down the valley.


Don't forget the distributor, cooling pipe, advance hose etc... Sure doable, but the more bends in the throttle cable, the less smooth it will work. After all, the engine was designed with a front engined car in mind...
quote:
Originally posted by Kid:
quote:
Originally posted by 72pantera:
Kid, if I recall correctly, the throttle cable links up to the driver side of the stock autolite carb. About maybe 3-4 inches from the center point of the 351. I would think one would not run into any issues running a cable down the valley.


Don't forget the distributor, cooling pipe, advance hose etc... Sure doable, but the more bends in the throttle cable, the less smooth it will work. After all, the engine was designed with a front engined car in mind...


With IDA's you need to modify the stock throttle cable so it is flexible to run down the center valley since it is not possible to get to the center linkage tower in a straight line.

You also need to add travel to the cable also.

Stock it is only 1-3/8". You will need a minimum of 1-5/8" if not 1-3/4" of cable throttle.

For that, you have to modify the carb end of the cable by disassembling it and removing the 7/16 od hard tube inside it.

I would think the IDF's will have the same issue.
The ignition advice you refer to in this blog is correct.

Simplest way is to go to a Ford solid state distributor and the Pantera Electronics ignition controller. Put a small cap on it so it fits. Your choice of coils. It will give you everything that is recommended and more.

Simplest combination of fuel pumps is just to add a Holley mechanical, plus a Holley electric with the Holley fuel pressure regulator and either 3/8" hard lines or -6 Aeroquip.

The P-E ignition controller has a special ramping and carb priming feature just for the electric pump.

You will have to run the engine to adjust the regulator to give you a maximum of 3 psi while running. No more then that.

You also need to change the stock Weber inlet fuel valves to the Jay Cee high pressure glass ball valves otherwise you will flood the first time you shut the hot engine off. AND, you will flood BIG TIME! Just like Niagara Falls, but with gasoline shooting EVERYWHERE!

So mount the regulator where you can easily reach it while the engine is running and away from the headers and even the potential of leaking liquid fuel down on any hot surface. Flash fires can be lethal.

If you are lucky, just your hair and eyebrows will instantly get singed off. If you aren't, you could wind up looking like Nikki Lauda...if you live that is?

The RX7 people have always had issues with the Webers containing enough volume in the fuel bowls and regularly modify them for greater volume.

In my experience this has never been a problem with running 8 stack Webers on an American V8.

IF this was going to be a regular problem, then you are using the wrong carburetor.

Run the new EMPI 51mm IDA's with the increased fuel bowl volumes. 11% more.

The only issue with that carb is going to be that the supplied chokes, 45mm, are really too large for the street and need to be throated down to about 42mm (which is still big for the street)

You have to work out which is the best combination of variables both with the type of carb and the tuning of them. Even with IDF's.

Nothing is going to be perfect and even if you buy a set of carbs "already set up" for you, you still need to "adjust" them to your tastes.

There is still a lot of work to do with a pre-built set up for you.

If you have never driven a car already set up with Webers, you will never understand the variables until you do. Most people will be mesmerized. It just isn't what they expect.

That's just the way it is.

I was fortunate in the first Weber set up I drove was in a yellow '71 Pantera.

It ran effortlessly, started instantaneously and pulled nose to nose with a 427 S/C. The only mistake is that I didn't buy the thing for $15,000. It had a the Australian "NASCAR" block in it too.

That definitely helped me understand what they did to the drive-ability of the car and infected me with a Weber virus that you can not cure.

Sometimes it's like Malaria and you just get a flare up and a fever. I'm definitely bent for life as a result.
Last edited by panteradoug
quote:
Originally posted by 72pantera:
So I got my linkage today, what do you know, they sent me the wrong one! I requested center pull, and I got the side mount. Any thoughts on if I could make it work, or maybe if it's even better?


For the Pantera a side pull isn't better. The center mount is the best solution.

You can make it work, but the side mount is really for a front engined car.

Send me the whole set up. I'll make you a center pull throttle. Big Grin
The Webers-on-a-Pantera subject comes up every few years. I have adapted various Webers to several cars, including V-8s. It is not simple to get both power and decent fuel mileage. One or the other is the norm.... First- in IDAs, there are five jets, two air bleeds and a replaceable emulsion tube & venturi- per cylinder- and they all affect each other during engine operation. The last time I checked, the cheapest jet was $6 USD. It is possible to tune them at home with primitive tools. It is also possible to go broke doing so. If you have never been involved with a set you already own and are impatent to use them, find and pay an expert. He will need the entire car or at least the whole engine on a dyno stand, for perhaps a month.
Second, Weber/Italy stopped making carbs in 1985, switching to EFI. There is a Spanish subsidiary that now remakes a few models, but most are Chinese/Taiwan/Indian copies that are known to leak thru poorly done castings. Be wary of E-Bay Webers! There are ways to ID genuine carbs but it's not real easy.
Finally, genuine NOS Webers have been on the shelf for 30+ years, so all o-rings, gaskets and the ball bearings in the throttles are bone dry & have shrunken. They will likely all need a rebuilding even if they're still in the OEM bags & boxes. On a 5.7-L V-8, 48s are about the smallest Webers you should try IMHO. 50s, 52s and even larger are second-mortgage territory for most of us. I know little about the giant "Webers" built entirely in CA and used on hotrod VW sand rails, some of which use 454 Chev-sized pistons.
As for IR- EFI, the neatest rig I know of uses 48IDA carbs with dummy fuel feeds & the venturis removed, as throttle bodies for hidden EFI systems. People that can build such things are even more 'special' than good carb tuners, and more pricy. Owners who want the vintage look and modern performance don't mind paying. One GT-40 owner has had a fabricator working on his 'real' Weber/EFI system for about 5 years.
The simplest thing to do is call up Jim Inglese, tell what you have and buy a jetting package from him.

The tuning discussions all seems ironic to me. I set up my first set of Webers on a Boss 351 in 1980 with the help of Jim Inglese. He was a "head hunter" back then as a profession and an amateur tuner and had bought boxes of jets and was willing to help out.

He literally lent me every combination between 1.10 and 2.00 fuel and air correctors. Only a few immulsion tubes, F7 (which I already had), F5, F11, F15.

Chokes 37 (which I already had) 40, 42 AND 44!

The idles were limited then because there was only one jet holder, a 1.20.

Pump jet bypass valves, blank .40, .70, .80, .90, and 1.00.

It took me about 4 weeks working every day, weather permitting.

Who was I to argue or refuse such a deal?



I am going through the jetting on this setup again now simply for one reason.

So many people have gone to tuners who have put them on dynos and come up with set ups that are different enough from mine, share the tune specs, that I need to try those tunes.

How can I argue with a dyno tune right?

I can say one thing with reasonable certainty. The wheel is round. The sun still comes up in the morning and water is wet.

My setup is right, or that's as right as you can get them. IF the tunes given to me are for real, than SOME of these dyno geniuses are just plain full of s h i t.



The only thing I can not speak for is how the larger bore IDA's work. I'd like to try the 51mm EMPI but the Hall manifold needs to be ported for them and if it sucks, there is no going back. Manifolds have become very pricey lately. Big Grin

Bosswrench is referring to remarks that have been made by the Shelby race team that 48ida's were showing that they were a little small for the 289's. Restrictive is the term they used.

THEORETICALLY the bore of the carb should match the size of the intake valve. With a 351 that's something like 53 mm. 48's are way too small for a 427. The 58IDA's were made for the 427 Fords. It is said only four sets were made.



There is no way you can run the idles as lean as some say they are. The exhausts will pop. Pop is an understatement. You will blow the baffles completely out of the mufflers.


I have some old Walker Turbo mufflers that got blown out that way. Roll Eyes



You can't run as heavy on the street with main jets as some say. The ratio is correct but the volume of fuel is for running flat out at LeMans FOR 24 HOURS!


With the IDA's the third transition hole helps, but sometimes it is still there. Depends on the weather?



I think that most of the problem with IDA's in the past, now, and in the future is a very simple one. New Weber owners have no idea what this setup entails, and they just presume that it is going to make THEIR 289 (or substitute your CID here) like a full race boogie 427.

Know what? Bunk! It ain't going to happen.

You are going to have a heavy idle (like a 750dp Holley), you are going to have fuel reversion (even with a special cam), some days the transistion flat spot will still be there and they are going to change with the weather. One day nice, next day miserable.



8 stacks are racing setups, pure and simple, with all the rights and privledges. PERIOD. Guys like Inglese have made them streetable...sometimes only marginally.

I don't think it really matters much if they are IDF's or IDA's?

Simplify your life, buy the tune from Inglese. He knows what he's doing. If "you" don't like the Webers after that, simply put, they aren't for you, because that's how they are.



Incidentally 72Pantera, very nice set up. Setting them up from scratch for me is great fun. Hope you enjoy it too? Smiler

Best of luck and enjoyment with them.
PanteraDoug, thanks for the compliment, they are 48IDF's if you are wondering. I must be honest, I'm not actually setting them up from scratch myself. I got most of the parts of the set up together and took it to my local shop, they do great work. It actually wasn't too hard to get most of the stuff. Linkage was kind of a pain to sort out, mainly just the waiting for some parts that are in small production batches. Talked to Jim; great guy, big help. Bosswrench, it is clear that you are just hating on webers, maybe they are not your thing, maybe you had a bad experience with them. That being said, if you wish to carry on with your unsolicited put down of webers,I suggest starting another thread. A majorly of individuals in this thread are excited to start/complete there own weber project.
quote:
Originally posted by 72pantera:
PanteraDoug, thanks for the compliment, they are 48IDF's if you are wondering. I must be honest, I'm not actually setting them up from scratch myself. I got most of the parts of the set up together and took it to my local shop, they do great work. It actually wasn't too hard to get most of the stuff. Linkage was kind of a pain to sort out, mainly just the waiting for some parts that are in small production batches. Talked to Jim; great guy, big help. Bosswrench, it is clear that you are just hating on webers, maybe they are not your thing, maybe you had a bad experience with them. That being said, if you wish to carry on with your unsolicited put down of webers,I suggest starting another thread. A majorly of individuals in this thread are excited to start/complete there own weber project.


Hating them? No not at all. As I said, you can't understand until you have run them. Webers I suppose are a love/hate relationship?

I've been running them on my car for quite a while, since about 1980. IDA's though.

I'll take the hint and stay out of your discussions from now on. No problem. Wink

Best of luck with them.

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