Oxygen sensors

I can just tell you of my experiences with Weber 48ida's on a Cleveland.

I could claim to be an expert on Webers on a "C" but that would be as ridiculous as claiming to be an expert on marriage because I am married for 38 years? Don't go there!

I have been running them since 1978.

What I have found is that virtually every engine series, i.e., Ford 289, Ford 351W, Boss 302, 428, 427, 429,Boss 429, will have a different combination, i.e., a different ratio between the fuel jet and the air jet.

In the case of the 351C, the PROPORTION that it really works with is 135-140 fuel jet to 160 air corrector. If that suggests to you that perhaps the exact fuel jet may be a 137.5, you may be correct. THAT is where racers would be talking about drilling the jets in order to get an in between size.

When you increase the size of the fuel jet, then you stay in proportion with the air corrector.

You can run the mains all the way down to 125 and all the way up to 170's.

I think that where the dyno will indicate the most power will depend on other factors such as the cam timing, ignition timing and exhaust configuration as well as the flow numbers of particularly the intake port/valve configuration.

Webers like a lot of advance, both initial and total. 16-20° initial and 40° total. I have no explanation for it but it is so.

I find the best overall jet combination at 135f/160a, but the engine will respond all the way up to 175f mains and the plugs read nice rust brown at that level.

When I did my testing initially in 1978 with Jim Inglese's help, he was supplying the jets on a loaner basis in trade for my information. We had to stop at 175f because he didn't have the corresponding air correctors for anything bigger.

The jetting that he would recommend was what I had come up with. 135-140/160. His feedback was that he thought even those were ridiculously heavy since the 289's were running on 125f and the 427's, 135.

Dyno testing then was not in the cards.

You run LOW fuel pressure with these carbs. 3-5psi like what a stock fuel pump puts out. However, Gene Berg makes "glass ball high pressure inlet valves" for them that are necessary to keep the carbs from perculating fuel and flooding the engine when it is at running temperatures and you shut it off. Also you need the asbestos carb to intake manifold gaskets. If you don't do that combination, the engine WILL turn into Niagara Falls.

The glass ball inlet valves are CHEAP INSURANCE at any price.

As far as the emulsion tubes go, the two that are the most commonly used with the Fords are the F5 or F7.

Stock 48 ida's will normally be supplied with F7's. That is because the current application for that carb is a VW Dune Buggy and it likes the F7's.

The Ford's run ok with them but some tuners like to lean out the mid-range rpm by changing to an F5. I frankly don't see the difference but a Dyno might?

I thought that the best combination of "chokes" were the 42mm. You definitely can feel additional "torque", i.e., down low power with 37's, but the 42's are MUCH better at the top of the rpm range. Depends how you drive the car or where you want the power.

Back in the day when Hall was selling the complete set up, he was using 32mm chokes. Those you need to cut out of aluminum billet.

That is where HE liked the power coming in but those really will top out at under 5,500 rpm's and the car will just hit a brick wall.

I know that the 289 Fords run under Shelby ran 42mm chokes and some said they were restrictive at about 6,700 rpm.

I was told that the Group 4 Pantera's ran 44mm chokes. That I can't verify and probably unless you actually had a "Factory Spec Sheet" stating that, it likely would vary from car to car depending on who set the engine up and what type of racing it was going to that day.

As far as the idle circuit goes, you are really stuck with what it comes with. .70/120's.

At one time the 120 idle jet holders,  (which really are a  combination of idle air jets and emulsion tubes) were all that was available. All you could do was lean the .70 idle jets down to a .65. If you went further to a .60, then the car will severely backfire through the exhaust. Severe enough to blow out mufflers and possibly break the top of the pistons above the top piston ring.

Recently there has been an availability of additional idle jet holders in sizes never before available. Some say that they have been able to reduce the idle heaviness by coming up with a new leaner combination with bigger air jet sizes? I have not played with that.

The issue with the original Weber set up is that you are idling on A/F ratios in the 12's which normally is the zone in which you want your A/F ratio under full power, so the result is that the idle leaves a black slimy residue on the exhaust pipes and the fumes just plain smart you eyes at idle.

This set up was always just intended as a "racing application" so there was never a fix for that.

Additionally, the engine generally runs on just the idle circuit up to somewhere in the 2,800 to 3,200 rpm range. It will vary depending on the atmospheric conditions A LITTLE. Often drivers will complain of a flat spot in the power curve at those rpm's. I admit that it is there with the two hole transition and mostly gone with the three hole.

This is where the third transition hole comes in. It is designed to cover as much of that flat spot as possible and generally works well or well enough to make it almost disappear while driving.

It will not change your IDLE A/F ratio. You can't. You are stuck with it as THE compromise to run these carbs on a street car. If you are stubborn like me, you will continue to try, think what could Doug possible know,  but continued trying to lean out the idle is likely at the expense of broke pistons, piston rings and mufflers, so don't say that I didn't warn you.

The only solution really to clean up the idle is to go to an EFI setup on that intake. Then the CPU will take care of the idle issues.

And yes, I installed a oxygen sensor thirty years ago, installed an A/F gauge and gave up long ago on cleaning up the idle and went to an EFI.

Have fun but don't be surprised if running these carbs turns into more of a "life style thing".

What manifold is that? I don't know anyone else who is running an IR manifold with runners that long.

My exhaust system is one of the old Hall off road setups. It does not have mufflers, but rather two resonators on each side. I've had it for 45 years. I had the resonators opened up and repacked. It looks great but it's still loud

Those look like Mind Train mufflers, not Hall's.

@joules posted:

What manifold is that? I don't know anyone else who is running an IR manifold with runners that long.

I believe that is an origianl Detomaso Weber intake. The carb flanges are much thinner then Hall's so it makes the runners look longer.

They were originally painted black from Detomaso.

The intake manifold on my car is a factory DeTomaso Weber manifold, built by Holman Moody for their racing team. These manifolds were very thin and prone to break so only about 16 were made. Pantera racer, Hugh Kleinpeter, from whom this manifold was bought in 1976, indicated that only four made it to the US. He had it machined to keep it from cracking, and I've had it on and off my car for 45 years without problems. 

In checking further, I find that you are correct about the exhaust system being a Mindtrain system; I bought the car in 1979 from the first owner and at the time paid little attention to what I bought, I was so overwhelmed by having a Pantera. Later someone must have told me it was a Hall system, so I never questioned it. Yes, the exhaust has a bit of a crackle to it, but I see from an older post that a crossover pipe can solve that.

That may have some advantages, but I don't like the appearance.

I learn a lot from you all.

I don’t know if I’m qualified to comment, but I run three DCOE40s on my TVR, and have been through them a number of times.  The engine is a Triumph TR6 2.5 liter straight 6.

I found that I’ve gotten a lot better low RPM performance by running significant advanced timing, even at idle, and then limiting total timing at high RPMs.

But as Doug has pointed out, I have had people behind me, complaining that their eyes were burning after following me for a little bit!

Rocky

I run 28 degrees of advance and get the ‘stinging eyes’ complaints as  well

Hum? 28°? I've found the Boss 302 number of 16 about right for initial advance.

Webers like 40° total on a Cleveland.

I can say that often with a single Holley carb, you can't run that much initial advance without inducing "run on", i.e., the engine running after the ignition is turned off.

Also, when you switch to aluminum heads, generally you reduce the total to about 32°.

@rocky You are correct about eye watering following you at Inde Motorsport Raceway.

I was thinking that was mostly due to my incredible speed!

😎

Thanks Doug, appreciate all the info -  I'm interested by everyone's 'eye-stinging' comments as that has been my experience too.  My last effort to reduce idle richness had negative overall effects so I'm going to change it back to your stated #s and ignore all the sting & fumes.  That said I might try F5s instead of the 7s. Chokes are 37mm, certainly don't want anything larger given the type of (too infrequent!) real use the car gets.

Tom, are you still running 150 mains/210 air like in older days?  Engine looks great btw!  Regards, Nate 

Meant to include this showing where I added 02 bungs...not as close to the collector as maybe ideal but easy to get to.  Haven't used them yet but definitely on the 'to-do' list

Hi Nate,

The numbers you mentioned above are from my old set of Webers which were replaced about four years ago. I simply installed the new set and started driving without looking inside. They run very well, but rich, but I'm not changing things. I've done that too often without much improvement. I spoke to Jim Inglese years ago, and he sold me a bad full of brass. He said Webers are simple and need no fussing after they're set up. He's a great salesman.  I'm 'renovating' the engine compartment, lots of new stuff, and will open up a Weber shortly to see what I've got.

the main problem is the idle circuit since you spend most of your time driving in town on that circuit. Once you get out of that people will be too far behind to get burning eyes. Every once in a while, I go back to my 650 Holly and its stronger, but it sure doesn't look so cool. 

My overall view is that folks just don't know how to relate to the set up.

The real determining factor is the difference of an IR, i.e., individual runner induction v. a single plenum system on a V8 engine.

I like to say that it just is not going to make your 351 into a 427 no matter what you think.

Dyno tests have definitely shown that there is actually more horsepower gains available with a single four barrel carburetor on a single plenum intake manifold available.

That simply does not tell the entire story though. You don't drive a Dyno. It is only a tuning tool that puts you in the private corporate box in the ball park.

The rest is up to you to apply the data to.

The MAIN benefit to the Weber induction system is that it is much more responsive to throttle openings then the single four barrel can be and secondarily, isn't subject to the loss of fuel delivery caused by severe cornering and braking like Holley's are.

Optimum intake runner length from carb throttle opening to the intake valve opening is obtained with the IR intake and the eight accelerator jets are mostly responsible in combination to that effect.

Consider that the early 1969 Boss 302 Trans Am racing induction of two Holley Dominator carbs on an individual runner intake manifold have exactly the same "issues" as the Webers do.

That is caused by the intake manifold design, not the carburetors.

I have actually found that the best combination of maximum naturally aspirated V8's is a 2x4ble carb on an equal length runner intake using vacuum secondary carbs.

On Fords, that combination only exists in two set ups. 1) the dual 4 big block FE like the 427's and 2) the C60A small block "Trans Am" intake.

The small block intake being much better engineered since it actually has equal length runners much like a tunnel ram would but has dual plenums which are connected together.

So there it runs all day on a single set of two barrel throttles to about 3,000rpm's, then begins to open the second carb throttles like it is a double pumper, then allows the vacuum secondaries to open on engine demand. So the induction is completely progressive.

My small block is a 347 in a 302. It is using two Holley 1850 carbs. So with the linkage it responds like a 600 Holley double pumper with boosters because of the vacuum secondaries. Those only open as the engine demands.

Some racers use an adage that the Holley carb size should be about twice the size of the cubic inch displacement. In that case that would be around a 700cfm carb.

I have run a single Holley 750dp, e.e., a 4779, on the Cleveland which is just a hair too big.

I have run a Holley 2x4 list 3300,3301 combination on the 347 which would put it at about 725cfm combination which works really well.

That considering the adage seems to explain things.

Another racer's adage which you might find interesting is that the dyno horsepower is going to show about 2x's the measured headflow.

So in the case of the 347, those are AFR heads and their test numbers show 296cfm at .550" lift so about 592hp which seems about right.

My A3 heads on the Cleveland show about 330cfm at .600". So about 660hp on that one.

Personally I looked for an intake manifold like that for the 9.2" Cleveland but it was never made by Ford Engineering. One has never emerged. You would have to adapt the Shelby 2x4 Boss 302 intake to a 351 Cleveland and that would really be a Rube Goldberg combination unfortunately of a VERY expensive intake (if you could even find one).

So to clean up the idle on the Weber 48ida system, you need to abandon the carbs and go to an EFI replacement. There are Weber look a-like EFI throttle bodies and at least two CPU systems available to control that.

One by Holley and one by FAST which is the Edelbrock in disguise. Both will clean up the idle and both will maximize the induction as seen by AI.

There is a difference in feel between the EFI and the Webers and the main complaint about the EFI is just that it is too smooth in comparison but in many instances the desired improvements searched for are really just a re-examination of how to reinvent the wheel. Maybe looking for the pot of gold at the end of the rainbow?

Incidentally, the air corrector to use with a 150 fuel main calculates to 171 air, so the answer is try a 170 air or a 175 air on a Cleveland.

A 210 air would be for a 289 set up. It has a different proportion of fuel to air and they do not translate back and forth to each other.

I am not telling you this from theory but from actual seat of the pants testing that I DID, ME so ANYONE else telling you otherwise is trying to sell you a bridge with a toll booth so good luck on that.

As an aside on that testing, most of the witnesses to those events have passed or moved away. The Police involved have retired so the stories of that are now just MOSTLY contained in local "folklore".  Fortunately for EVERYONE involved the Statute of Limitations HAS expired!

Hey Doug,

As always, thanks for the input. you are a wealth of information.

If you don't mind Just for comparison, what are your other numbers for: I know you covered some.

1. IDLE JET...  Idle jet holder (105), idle jet (60).

2. MAIN JET....  air correction jet (155-175), emulsion tube (F7), main jet (160). The numbers I added were suggested to me by Jim Englese.

Idle: .67f/1.20 air/ jet holder. emulsion tubes: F7. mains: 137/160

chokes: 42mm. Pump jets 1.0

You need to make the .67 idle from a .65 and drill it out. The same with the main fuel. You use a 135 and drill it to 137.

It will also lean out with altitude like for Colorado but I don't know what you can do there. A Pike's Peak Hill climb is an issue.

Think of the Webers as an analog system that can only be modified by human interaction and the EFI system as a digital "self learning" system in the sense that it adjusts it's fuel delivery pattern according to predetermined criteria programed into a script but because it is digital can make very small incremental changes instantaneously as the engine is running.

It aims at pre-determined optimal A/F ratios according to rpm, velocity, air temperature and engine load.

The EFI has limitations and will vary the maximum power available according to the limitation of the atmospheric conditions but it will come closer to optimal.

Think of the air/fuel proportion like making tomato soup. You are aiming at one consistency. If the engine needs tomato sauce, if it is too thin, it is tomato juice and is to weak to make power and if it is too thick it is tomato paste and too thick to make power.

A 125 fuel main is feeding the engine tomato sauce with a teaspoon and a 175 main is feeding it with a ladle.

The other engines use different "consistencies" then the Cleveland needs.

The 289s like tomato juice. The 427s like tomato paste.

The 150 fuel mains mentioned was something that Reggie Jackson mentioned years ago about his small block Chevy engine running Webers. Even though there are similarities in cubic inch displacements, there the "consistency" changes. The Chevy likes Tomato Juice, maybe even "V8 Juice"? The Cleveland will get agita from that.

Incidentally, I tried to deal with Kleinpeter back then also. I don't remember exactly the year but it was in the '76-78 time frame.

Since I was just beginning my Pantera experiences, I found him to be a "SuperFlake" and didn't need "the only Weber set up in North America" nor even his "flip top" race car, which was also for sale then.

I discovered Gary Hall and Hall Pantera and Gary had just cast up his intake manifold and was very helpful at any time. So we were at least "simpatico" whereas Kleinpeter and I were just ying and yang.

I noticed that someone already has found the progression on the idle downsizing for you with the 60/105 combination and has tried to lean the idle down.

I don't know if it is the volume of fuel that is making the idle too rich or the ratio of the fuel to the air corrector?

I have to PRESUME that the original .70/1.20 combination is the right ratio since that came from Weber directly? I'm thinking though that because the application was for a VW Dune Buggy, Weber may have intentionally jetted them heavy to avoid an unmuffled open header from "leaning out" the engine under wide open throttle usage?

It isn't coincidental that Holley does that with the "double-pumper" series and that is their explanation for those carbs having a "heavy idle". The Holley idle can be leaned out by increasing the size of the idle air restriction which is Holley's version of an "air corrector".

The math that I have for the combinations of leaning the idle down more using the original Weber proportion is as follows:

60/102

55/95

50/85

45/77

40/68

If I was STILL adventurous, I would explore if these combinations are available (they are) and test them to see if they would work?

The .40 aren't quite 1/2 of the original .70's  but pretty close. I find it difficult to conceive that those would work at all considering that the 70/120 was originally for VW 4 cylinder Dune Buggies, but the process is usually that when you find something that will work like the 60/105 like you have, you keep going one step at a time until it no longer does work and back off

It is entirely possible that the 60/105 that you have now is as low as the idle jets can go but you won't know that until you try to go lower, one step at a time?

So the first question is will the next size smaller work and if it does, how rich is the idle? Does it make the idle cleaner?

You need to check with Weber jet suppliers to see what is available now to see if that is feasible before you start. All these combinations now seem to be available.

It's just a thought, but this is how you determine if you have reached the optimal tuning.

According to Alfa1750's ad, holders are available now all the way down to .40. The fuel jets as well.

https://www.ebay.com/itm/29178...7:g:TP4AAOxynwlTcmKD

I'm just trying to be helpful and anticipate your questions.