[BruceWilkie]

Slick1 the manifold has to 1) compliment the runner in the head to get the most out of it. If the head port flows a given number and the manifold flows the same number it does NOT mean they will work in concert with each other and still flow the same number into the cylinder. Properly executed their is potential to gain overall flow. Think complimenting angles/shapes as the flow transitions from manifold to head. 2) equal air flow in opposite direction does not address what happens when fuel is added to the air. Fuel and air though both "fluids" have different dynamics due to weight. Even with dry flow there are aerodynamic considerations. Primarily venturi like effects. An exaggerated example would be flowing a carb in reverse, but the principle is what I'm pointing out. Bryce Mulveys method makes sense on an exhaust manifold outlet providing he goes in the direction of flow of course.
Personally I hope a lot of the Chevy boys do it his way on their intakes.

[Tom Vaught]

Quote:

"respect your knowledge and enjoy your posts-
97% of 300 is 291- still a pretty good intake"

Not a fat finger that time, need my reading glasses! I looked at the calculator number with my normal glasses and misread the 1 as a 7! LOL 291 cfm is correct

Tom V.

[Tom Vaught]

Quote:

"Bryce Mulvey of Dr.Js performance is the guy who prepares & ports the intakes in this manner, it was featured in the Engine Masters/Popular Hot Rodding issue several months ago! It is one way to go about it that does truly isolate the runner being worked on regardless of which way the air is flowing to me?"

I do a lot of Ford Intake manifold work as the best NA engine is also the best Turbo engine as far as flow distribution goes. Flowing each runner separately only
tells you part of the puzzle. You also need to know where the air is going when all of the runners are flowing as the intake valves are opening and closing many times in one second. The intake plenum sees constant draw on it and the running act like a bunch of springs vibrating. If you have an open plenum you need to see the flow distribution on all of the cylinders at the same time. Hard to do unless you have the right equipment but very valuable info if you can get it. JMO

Tom V.

[Region Warrior]

So, anyone know how much diff from runner to runner on an RPM intake?

[Steve C.]

Skip- Holley Street dominator intake (modified by Dave Bischopp) with same 1/2" spacer and HP950 carb was 401hp at 4000 and 589 hp at 5600 rpm compared to the 493 hp & 566 hp with the Torker II intake. Both had peak torque at about 4500/4600 rpm with 576 ft.lbs on the Torker II and 589 ft.'bs with the HSD intake. Performer Rpm intake had the same 589 ft.lbs. at a lower 4400 peak rpm.

[gearbanger]

Steve, what are you saying? Are you saying the torquer made 92 more hp at 4000 rpm?
And the torquer made less hp at 5600 rpm?

[Steve C.]

Sorry if I made any typo errors, here it is again...

Torker II
4000 rpm 398 hp
5700 rpm 566 hp

HSD
4000 rpm 401 hp
5600 rpm 589 hp

Performer RPM
4000 rpm 423 hp
5800 rpm 580 hp

Victor
4000 rpm 402 hp
6000 rpm 600 hp

All intakes tested with a 1/2" open carb spacer and the same HP950 carb.
And all intakes port matched to my heads except the Torker II

[Skip Fix]

Since my T2 was more opened up and stayed with the Holley, so probably could be better numbers than the one Steve tested.

Most dual planes I have flowed had different numbers for upper and lower plenums on almost every cylinder. The larger plenums and runners on an RPM over a stock intake might be a little better but I've seen 5% difference between upper and lower runners.

[Ron H]

Steve, just to finish the comparison. Is it possible to add the torque numbers to this great info?
Thanks

[BruceWilkie]

TomV, you agree then that flowing the manifold backwards is indeed something all the Chevy boys should do! I had a good laugh when I read the article. Even without your fancy equipment it should be a no brainer to test in the normal direction of flow.

[Steve C.]

Torque numbers:

Performer RPM
3500 491 ft.lbs.
4000 555
4400 (peak) 589.1

HSD
3500 476
4000 527
4600 (peak) 589.0

Torker II
3500 478
4000 522
4500 (peak) 576

Victor
3500 487
4000 527
4700 (peak) 595

This of coarse doesn't indicate the whole picture, lots of numbers and things going on in between. And being a one finger typist, and lazy, I'm not going to type it all here ... so if interested e-mail me and provide a mailing address and I'll send copies of the actual dyno sheets.
[email protected]

[Tom Vaught]

Quote:

"TomV, you agree then that flowing the manifold backwards is indeed something all the Chevy boys should do! I had a good laugh when I read the article. Even without your fancy equipment it should be a no brainer to test in the normal direction of flow."

1) I did not see the article, maybe some can post it.
2) If I can screw up the chebby boys performance, then I think that is a good thing. LOL! Maybe I can get them to mount the carb with the throttle level on the passenger side too.

3) All kidding aside. You really need to know what the air distribution is in the intake system. If it is off in a steady flow test it will be off in a dynamic test too. You can put ego sensors into each hole of the exhaust and pick out
some of the distribution issues but not necessarily all of them. EFI is a crutch in some ways as when you have a manifold with poor air distribution people can take away fuel from that cylinder if they have individual injector control for duty cycle. That just means that you gave up a bunch of hp on that cylinder in my mind.

I have a patent on a method to very accurately measure air flow in all of the cylinders at the same time using a spin-tron and accurate cylinder flow equipment. Smokey, if you read some of his articles in Circle Track was after the same thing, quality air distribution.

Tom V.

[SLICK1]

Bruce W. & Tom V. your points are duly noted and I truly value your opinions, but I did see quite an improvement in my intake after these mods were performed! Now the question is, could it have been even better if I had it prepared by Wilson or any other porter? I honestly don't know, but I will say this, all though it is not the most common way to do it, it simply worked for me and my combination and I do feel it was money well spent on my Lil D-Port motor.

[Tom Vaught]

Quote:

"Now the question is, could it have been even better if I had it prepaerd by Wilson or any other porter? I honestly don't know, but I will say this, all though it is not the most common way to do it, it simply worked for me and my combination and I do feel it was money well spent on my Lil D-Port motor."

I have one of the first Victor 850s ported by Keith Wilson. I later loaned the intake to the Butlers and a lot of other Pontiac engines picked up on power, Wonder why? LOL!
Wilson's intakes are works of art, are flow tested, but the real magic is that he does an outstanding job of port matching and port shaping to the head. His intakes are in great demand in NASCAR and other venues. Talk to Gabby as sometimes Gabby posts on this board. Gabby is a pal of mine.

Tom V.

[BruceWilkie]

I had previously stated that flowing in reverse was a bad idea and it is. However, I reread the article and they are BLOWING through the manifold. This is a valid method for flowing the manifold and for equalizing the runner flow. IN THE MANIFOLD ITSELF!

This method DOES NOT account for what happens when the head and manifold are bolted together. (or the actual carb you intend to use)While you can acheive equal or greater flow from your manifold intake runners(than your head ports) you are not addressing what happens at the head. The head port AND manifold need to be ported together to insure flow is directed to where it needs to be throughout the valve lift curve. I still say drawing the flow through with suction from the chamber side of the head better resembles a running engine than blowing through an adapter on the manifold. (although a supercharged application could be different situation) In summary I feel the best result with a typical flow bench is to do what you got to do to support it but mount the head to the bench, the manifold to the head, and your carb to the manifold. You must address the entire system for BEST results, not just equalize runner flow to match head flow that was measured with a radius around the port that does not in any way resemble the manifold runner.

[Tom Vaught]

My Opinion for what ever it is worth is that you need to do a systems approach:

You need to have the numbers on each port (Intake and exhaust) for each head.

You need to be able to flow the intake on the heads to see the losses caused by the intake manifold. Same deal for the carb.

If you read Smokey Yunick's book he shows you how to do this using an engine stand, a modified pan, and some other parts along with your flow bench.

Others have used his concept too:

http://www.theoldone.com/articles/Ci...rl_Power_5.jpg

Maybe you never saw the articles

Tom V.

[BruceWilkie]

Thanks Tom, you and I have both learned from Smokey's writings.(among others) It is all about a "systems" approach. Though I got to credit Kenne-Belle for opening my eyes on the manifold/head porting concept way back in the early eighties.(port matching a Weiand "Team G" buick V6 intake would kill flow at the valve if bottom of intake runner was blended to bottom of head port.)

[SLICK1]

Originally Posted by BruceWilkie

I had previously stated that flowing in reverse was a bad idea and it is. However, I reread the article and they are BLOWING through the manifold. This is a valid method for flowing the manifold and for equalizing the runner flow. IN THE MANIFOLD ITSELF!

CORRECT! With the manifold bolted upside down to a fixture that either represents the carb mounting pad of a 4150 style carb, a 4500 style carb or a quadrojet style carb! And I'm in "STRONG" agreement that the ultimate in performance would be with the heads, intake, carb, and probably even a tube coming off the exhaust port to simulate everything in a functional manner, but I had the motor assembled and the heads were ported long ago and I was just trying to find a lil more power, and did!

[joes455]

Has anyone done any testing using a plenum divider installed in a TQ2 or a Victor?In one of David Vizards books ,he mentioned doing this.This mod had good results.

[455-4+1]

I will be testing variuos ones in a victor in the next month or so

Will be using dual Wideband o2's with the data logger to compare results

I will post the results when done