New engine/low HP

I'm no expert, but from all the other postings that I've seen over time the Performer intake is probably choking your engine. I have a Blue Thunder intake and all fit under the screen (barely) when I was running it.

Art, one thing you might try that is relatively inexpensive is maybe a differant air cleaner?? I know the air has to make some sharp turns before it can head down the carb and if there isn't a lot of room between your air horns and the top of the air cleaner, it acts like a restriction. I heard thos dog bone ones are actually pretty good.

Hi Art,

2511 runs a .030 over Cleveland, Performer, Holley 670, a dropped Moroso cleaner that makes the air work to get down the carb throat, and the big Ansa GTS headers/mufflers. My cam is very mild compared to yours, but my chassis dyno had HP climbing to 292 at about 6150 until it dropped off like a rock.

What size is that Big Bore choking your exhaust down to? Primaries?

Sounds like air flow issues - intake/exhaust/both?

Larry

Art the intake's gotta go... some of the other biys can give you a recommendation but thats a street intake. I have a torker you can try and it fits under the screen with a Moroso air cleaner brand new black. Both are for sale.

The power valve which did you select .. if I remember correctly you need a vacumn guage and what ever vacumn you have at idle you need 1 point higher or lower. its been a while maybe some one can clarify that. Jetting .. you need a selection of jets DYNO day.

Keep trying the HP will come up.

Ron

Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

Art,

the dyno is the best place to diagnose a problem. I have more questions than answers at this point.

First, my random observations. Your motor is making about 407 bhp at the flywheel, which is about all you're going to make using the cast iron 4V heads without porting & a good valve job (multi angle). Although the cam is rated for power out to 6000 rpm by Comp Cams, thats with a 351 cubic inch motor, the extra displacement of your stroker moves the power band lower in rpm, I would have guessed power to 5750 rpm, but 5650 is close enough. David Berman had his motor dyno tested with an Edelbrock Performer adapted to work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at around 6000 rpm, feeding a 408 cubic inches. I never liked the Performer myself, but David's dyno results has given me a new found appreciation of that intake, you can make more power at the upper rpm with other intakes for sure, but I do not believe the intake is what is "choking" your motor. It may very well be the characteristics of that cam to drop off like a brick above the powerband, rather than the torque curve tapering downward at a slower rate, which is why sports car guys normally want a wide flat torque curve, rather than an upward tilted one. The upward tilted ones drop off faster beyond peak torque. When all is said and done, you may very well need a custom ground cam to get the characterisitcs you want.

Having written all that, I myself would not be satisfied with the performance of your motor either. I would expect it to perform better too.

OK, here's my questions:

Do you have assurance that the person who built your short block did a good job with the rings as far as getting them to seal well in the cylinders?

Did the dyno operators run any air/fuel ratio numbers while your motor was on their dyno? If so, what were the numbers like between 4000 & 6000 rpm?

What components is your ignition composed of, and how old are they?

What is your ignition timing specs?

What parts are your fuel delivery system composed of & how old are they?

What make & size is your carburetor?

What are you using for an air filter and was it installed during dyno testing?

What size are the exhaust pipes of the mind train system, and what type mufflers does it use?

Have your heads been ported and had a multi angle valve job?

How do the specs of the Isky 8005A springs compare to the springs recommended by Comp Cams?

your friend on the DTBB

Thank You Dennis,
Art

quote:

Originally posted by 4NFORD:
I'm no expert, but from all the other postings that I've seen over time the Performer intake is probably choking your engine. I have a Blue Thunder intake and all fit under the screen (barely) when I was running it.

I am using a 3-1/2" tall round K+N filter. When I had the carb worked on this week, I had them mill off the choke horn in anticipation of squeezing a taller manifold under the screen. Milling the choke horn gave me no seat of the pants improvement. So, I don't think the air filter is holding me back?
Thanks,
Art

quote:

Originally posted by DeTom:
Art, one thing you might try that is relatively inexpensive is maybe a differant air cleaner?? I know the air has to make some sharp turns before it can head down the carb and if there isn't a lot of room between your air horns and the top of the air cleaner, it acts like a restriction. I heard thos dog bone ones are actually pretty good.

Larry,
The primaries (header tubes) are 2" OD which I guess makes them 1-7/8's. The exhaust pipe from the headers to the four glass packs is about 2-1/4" OD so I guess you would call it 2-1/8".
Thanks,
Art

quote:

Originally posted by LF - TP 2511:
Hi Art,

2511 runs a .030 over Cleveland, Performer, Holley 670, a dropped Moroso cleaner that makes the air work to get down the carb throat, and the big Ansa GTS headers/mufflers. My cam is very mild compared to yours, but my chassis dyno had HP climbing to 292 at about 6150 until it dropped off like a rock.

What size is that Big Bore choking your exhaust down to? Primaries?

Sounds like air flow issues - intake/exhaust/both?

Larry

Ron,
I don't know which power valve they installed. I also did not realize a Torker manifold would fit under the screen. Is that the later screen with the raised sheet metal section?
Thanks,
Art

quote:

Originally posted by accobra:
Art the intake's gotta go... some of the other biys can give you a recommendation but thats a street intake. I have a torker you can try and it fits under the screen with a Moroso air cleaner brand new black. Both are for sale.

The power valve which did you select .. if I remember correctly you need a vacumn guage and what ever vacumn you have at idle you need 1 point higher or lower. its been a while maybe some one can clarify that. Jetting .. you need a selection of jets DYNO day.

Keep trying the HP will come up.

Ron

Dennis,
They charged me $150 the first time which was just a diagnosis with no dyno pull. They charged me $130 the second visit which included three or four pulls? Their regular price is $180 with no changing of jets, $300 or $310 if they change jets. A dyno day would be cool!
Thanks,
Art

quote:

Originally posted by daleyracing:
Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

Dennis,
Do you have the same cam as I do, the Comp Cams #32-541-8 hydraulic roller? If so, what kind of rpm's can you turn? It sounds like your engine screams!
Art

quote:

Originally posted by daleyracing:
Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

George,
Russ Fulp built my engine, he has also built engines for Dennis Antennucci, Dennis Daley and Matt Meritt. Russ has a very good reputation. As for rings seating in the cylinders, I don't know? A problem started early on with excessive oil consumption, like a quart every 200 miles. That turned out to be bad intake gaskets (Mr. Gasket) that I replaced with Fel-Pro's. I'm not sure that has completely solved the oil consumtion problem, I suspect there is a little blow by going on. Russ says he sets his engines up loose, but I'm not sure my rings seated properly? The dyno guys gave me no air/fuel info. My ignition includes a new msd 6-al box with a 6500 rev limiting chip. The distributor is a Ford, Duraspark? The coil is an Accel Super Stock #8140C, a typical looking cylindrical unit. The coil is seven years old with about 18,000 miles on it. The distributor was in the car when I bought it in 1997, I've put about 30,000 miles on the car and distributor. The guys at the dyno shop set the timing to 34 degrees total, I noticed they plugged my vacuum advance, it is still plugged. I have all new fuel lines and filter. I have a new mechanical fuel pump that is supposed to be good for 120 gph. It is an Allstar brand #40263. The dyno guys watched my fuel pressure gauge during the pull and they said pressure never dropped below 6 psi. I have a Holley 750 double pumper with mechanical secondaries. I believe it is a 4150/4779. It was set up by Jet Performance for my new engine. I am using a 3.5" tall round K+N part #E-1540 air filter. The air filter was in place during the dyno test. The headers appear to have 1-7/8 inch primary tubes with 2-1/4 O.D. exhaust pipes running into four glass packs. The heads were not ported, but Russ did a multi angle valve job on them. I haven't found the specs for the Isky or the Comp Cams springs. I guess I should ask Russ why he chose to go with the Iskys. I hope you are wrong about the cam, (that intake sure would be a lot easier to change), but you seem to be very knowledgeable about this stuff.
Thank you very much for your help,
Art

quote:

Originally posted by george pence:
Art,

the dyno is the best place to diagnose a problem. I have more questions than answers at this point.

First, my random observations. Your motor is making about 407 bhp at the flywheel, which is about all you're going to make using the cast iron 4V heads without porting & a good valve job (multi angle). Although the cam is rated for power out to 6000 rpm by Comp Cams, thats with a 351 cubic inch motor, the extra displacement of your stroker moves the power band lower in rpm, I would have guessed power to 5750 rpm, but 5650 is close enough. David Berman had his motor dyno tested with an Edelbrock Performer adapted to work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at around 6000 rpm, feeding a 408 cubic inches. I never liked the Performer myself, but David's dyno results has given me a new found appreciation of that intake, you can make more power at the upper rpm with other intakes for sure, but I do not believe the intake is what is "choking" your motor. It may very well be the characteristics of that cam to drop off like a brick above the powerband, rather than the torque curve tapering downward at a slower rate, which is why sports car guys normally want a wide flat torque curve, rather than an upward tilted one. The upward tilted ones drop off faster beyond peak torque. When all is said and done, you may very well need a custom ground cam to get the characterisitcs you want.

Having written all that, I myself would not be satisfied with the performance of your motor either. I would expect it to perform better too.

OK, here's my questions:

Do you have assurance that the person who built your short block did a good job with the rings as far as getting them to seal well in the cylinders?

Did the dyno operators run any air/fuel ratio numbers while your motor was on their dyno? If so, what were the numbers like between 4000 & 6000 rpm?

What components is your ignition composed of, and how old are they?

What is your ignition timing specs?

What parts are your fuel delivery system composed of & how old are they?

What make & size is your carburetor?

What are you using for an air filter and was it installed during dyno testing?

What size are the exhaust pipes of the mind train system, and what type mufflers does it use?

Have your heads been ported and had a multi angle valve job?

How do the specs of the Isky 8005A springs compare to the springs recommended by Comp Cams?

your friend on the DTBB

Art,

Thanks for providing the info, sorry for the third degree.

have you spoken to Russ about this? I know who Russ is because other Pantera owners like Dennis A speak very highly of him. I would expect him to have built you a top notch motor, and am surprised to read you're having trouble with it knowing he's the builder. There's a mechanics code of honor by the way, one mechanic doesn't criticize or second guess the work of another, at least not publicly, ahem.... Mechanics are all a very highly opinionated bunch, become irritated easily. If we went around second guessing each other, we'd end up throwing burning carburetors through each others windows in the middle of the night. You've never heard of a "Holley-tof cocktail"?

Shame on your dyno operators for not taking A/F ratio readings! That would have provided you with very critical info (1) you have an air/fuel problem, or (2) you don't have an air/fuel problem. At least you would know to concentrate on other areas.

I wish your problem could be solved as easily as with a manifold swap too. You can always borrow one from somebody & give it a try, but I wouldn't go out & buy one until after I tested the theory with a borrowed manifold. If we lived closer I'd let you borrow my Holley Strip Dominator. Surely one of the OC guys has a torker you can borrow.

We are talking about 2 "possibly" unrelated issues, so lets make that clear, (1) your motor is not producing the power that we expect from it (2) your motors torque curve drops like a brick above 5650 rpm. Your peak torque, at 4000 rpm, is not what I would expect, which is why I say the issues "may" be unrelated.

Regarding issue #1, ring seal is very important, if they don't seal properly, then you'll never achieve the bhp numbers you are expecting. On the other hand, Russ is quite capable of building a good short block, so I would lean towards ruling that issue out. If fixing problem #2 doesn't resolve problem #1, a leak down test may be called for. I can also guarantee you that your heads need some porting to achieve the numbers you and I both expect for your motor. The exhaust port demands most, but not all, of the attention. The roof of the exhaust ports has a bump that needs removal, and a flat surface that requires blending out to the exhaust flange. The whole exhaust port (sides, floor) also needs to be blended and "straightened out" dimensionally. I would also like to see at least 2 1/2" tubing between the collectors and the mufflers. I have no experience with the mind train exhaust system, if it will support more than 400 bhp or not. I like the Magne Flo muffler, like those sold by PI Motorsports, better than the dual glass pack systems I've seen. But liking something, and having actual dyno experience with it, are 2 completely different things.

Regarding issue #2, while a single plane intake WILL make bigger bhp numbers for you, I don't expect the Performer intake manifold to affect the motor the way you desribe, i.e. the drastic drop in torque above 5600 rpm. It will roll the curve off, but not that drastically. Thats more of a symptom I would expect from a fuel problem, an ignition problem, or a camshaft design issue. I'm just not familiar with the Comp retro-fit roller cam, so I am unable to say if that's normal for that cam or not. Dennis A's engine has the next size bigger Comp Cam and pulls to the mid 6000 range just fine. He's running C302 heads of course.

I've had engines exhibit similar charactersitics before, once it turned out to be a lifter had partially come apart, the push rod was still in place, it wasn't making any noise, but the guts of the lifter were laying in the lifter valley, that lifter wasn't opening it's valve! That one busted my balls for several days. More common was the old Holley running too rich syndrome. A rich carb will make the motor drop off like that. I've seen a 351C that wouldn't rev beyond 4800 rpm for that reason. But I wouldn't expect that from your "tuner" carb.

I would also not discount the older ignition coil, performance of coils does taper off with age & use, and aftermarket parts quite often do not have the longevity of oem parts. The MSD box could have a defect also. Ohming the spark plug wires would also be a good idea, especially the wire between the coil & distributor. You may want to monitor the voltage supply to the coil or ignition box while its being run on the dyno, the Pantera electrical system may simply just be dropping the voltage to the coil or MSD box as the current draw increases. A method to diagnose that issue is to install a direct jumper between the battery & ignition using a heavy gage (12 gage) length of wire with alligator clips on both ends. Ignition issues are also something that can be easily diagnosed on a dyno with an engine analyzer.

One test you can run is to rev the motor in the driveway & determine if the motor hits a brick wall under those conditions (unloaded) or only on the dyno.

It's getting late Art, I'm running out of steam. I hope I've given you some ideas. Perhaps some of the other guys have ideas.

Your friend on the DTBB

Art,

Taking my daily look through eBay, I see there's a Torker on right now, finishing in less than 12 hrs and still at under $70 (for now at least).

At that price you could take the chance and resell it if its not for you.

http://cgi.ebay.com/ebaymotors/351-Cleveland-Edelbrock-...QQrdZ1QQcmdZViewItem

> David Berman had his motor dyno tested with an Edelbrock Performer adapted to
> work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at
> around 6000 rpm, feeding a 408 cubic inches.

He'd gain a bunch by moving to a Yates intake.

> Your motor is making about 407 bhp at the flywheel, which is about all you're
> going to make using the cast iron 4V heads without porting & a good valve job
> (multi angle).

Dan Haynes made right at 500 HP on unported 4V heads on a high compression
351C. He'd have made more with porting but the heads are not the limiting
factor here.

> The primaries (header tubes) are 2" OD which I guess makes them 1-7/8's.
> The exhaust pipe from the headers to the four glass packs is about 2-1/4" OD
> so I guess you would call it 2-1/8". exhaust pipes running into four glass
> packs.

The primary diameter is too large, the collector too short and the exhaust
pipe too small. If your mufflers are too restricitive (and glass packs are
often among the worst), you won't see much benefit from header tuning.
Some exhaust system rules of thumb:

OID = SQRT (Ex_CFM * 1.27/FD)
CD = 1.75 * OID

where:

OID = optimal internal diamter (inches)
Ex_CFM = exhaust port flow (CFM) at 28" H20
FD = flow density (around 80 CFM/square inch @ 28" H20)
CD = collector diameter (inches)

Primary lengths between 24 to 36 inches (for bank separated 4-into-1
on V8's with dual plane crankshafts)
collector length between 12 and 20 inches good for 8000 RPM

Mufflers should flow 2.2+ CFM per HP (the point at which there is a 1%
difference between mufflers and open pipes), 500 HP requires two 550 CFM
mufflers

A friend tested his unported 351C-4V heads (Super Flow at 28" water, in CFM,
stock single-angle valve job and 5/16" Manley valves with an MPG port plate)
and at your peak lift, they were around 180 CFM without a pipe. Plug in the
numbers:

OID = SQRT (180 *1.27/80) = 1.69 inches
CD = 1.75 * 1.69 = 2.958

Most Pantera headers have collectors way too short (5 or 6 inches) with
too small ID collectors and exhaust pipes and way too restrictive mufflers.

> I am using Isky #8005-A valve springs. Lifters were part of Comp Cams K-kit
> for this cam.

Comps K-Kit includes the springs and lifters. For some reason you're engine
builder chose not to use the K-kit springs. Comps standard hydraulic roller
lifters don't rev well. The Crane link-bar lifters have proven to rev much
better and Comp has recently introduced their version of a link bar lifter
but I've not seen any test data on those. Much care must be exercise in
picking the springs and lifters when trying to get a hydraulic roller cam
to rev well with heavy 4V valves and 1.73:1 rocker ratios.

> Your motor is making about 407 bhp at the flywheel,
> I have a Holley 750 double pumper with mechanical secondaries.

In addition to the Performer intake being a wrong choice for your set-up, your
carb is a limiting factor. 100 HP requires 140 CFM based upon a reasonable
assumption for Brake Specific Fuel Consumption (BSFC). The BFSC assumption
keeps us from having to guess at volumetric efficiency. A 407 hp engine uses
an actual 569.8 CFM. 4 barrel carbs are rated at 1.5" Hg but that is way too
restricitive on a tuned engine. 0.7" Hg is a more reasonable pressure drop
(too keep the carb from being a limiting factor). Converting to rated carb
CFM:

Flow @ 0.7 In Hg = (CFM Rating @ 1.5 In Hg)/SQRT(1.5/0.7)
569.8 = X / 1.46385
X = 834 CFM flow rating required

> I'd let you borrow my Holley Strip Dominator. Surely one of the OC guys has a
> torker you can borrow.

I offered up a Strip Dominator, Blue
Thunder, Boss 351, and Torker for a dyno test but I don't think he's interested.

But what about PI?

Art,
I basically have the same cam as Dennis A's but the seporation is for webers lift is 613.
and my 180's are 2" with 3.5 collectors. and 11:1 cr
so I need to get mine to the dyno.
Thanks
Dennis D

Dan what about step tube headers?
I always thought that an 850 DP Holley was the best "Performance" carb out of the box. It is ok on the street but a 750 is crisper.