if you had EGTs on the car you would understand why i say what i say.

 

x million, how many guys have burned up corners or centers because of airflow distribution?

 

Hi Shawn,

How does the Edelbrock pro flo XT look vs the LS6 or fast, or bbk for a hot boosted street/strip car? The Holley intake has the same style design as the pro flo XT with the large open plenum and the intake runners shooting straight down so the HP and torque curves should look similar across the power band.

The edelbrock pro flo XT has been out for 2 years yet I have never seen any valid side by side dyno chart comparisons of the pro flo XT vs a LS6 or fast intake. Only edelbrock pro flo XT vs LS1.

Edelbrock claims a 30HP increase over the LS6 manifold at high RPM over 6000. But my feeling is its probably giving up a lot of low and mid-range torque to achieve this.

So 20 ft lbs of torque lost at low and medium RPM's can equate to 40 ft lbs lost on a 15 lbs boosted hot street motor. This will definitely be a large seat of the pants loss when punching the throttle on a hot boosted street/strip car.

I am building a lightened 74 camaro, with LQ4, 230 to 240 duration and 590 to 600 lift cam, turbo 400, 3.73 gears, S400 75mm turbo, air to air intercooler, 15 to 17 lbs of boost, Meth injection on pump gas. Weekend street use with lots of 1/8th mile strip runs. I will eventually upgrade to forged internals with aftermarket heads and really crank up the boost to maybe 22 lbs. Car will weigh about 3250 lbs without my 200 lbs in it.

So what ajensen383, NicD, tomZ28 and I are asking is how does the edelbrock pro flo XT look on a hot street/strip car vs a LS6 or fast or bbk intake look as far as the powerband, torque curve, HP etc across the entire powerband. Not just peak HP. I would even like to see the holley in there.

No one wants to publish this (including edelbrock, beleive me I have asked them). So my guess is the edelbrick pro flo XT gives up a lot of low and mid range torque to gain HP at high RPM. My concern is Holley has the same basic manifold design as the edelbrock pro flo XT.

At what point does low and mid-range torque stop being important on a street/strip car? We know on fuel injected engines the intake manifold design is even more critical than the cam in determining the torque curve of the motor (depending on intake runner length). Sounds like you have a good bit of experience in this area Shawn. Many of us want to know and are looking for a cheaper alternative to the fast intake in planning our builds and for fast street and drag racing.

Hpbob1

 

Sorry to intrude on the conversation...but does anyone have some insight to the question I posed yesterday?

 

Shawn, I sent you a PM

 

Mr. Big- can you share some dyno data comparing the LS2, FAST and then the Wilson with us?

I would love to see a comparison of an LS6 intake with stock ported TB vs. a FAST 102mm and 90mm TB on a built turbo motor that spins to 7500rpm.

 

I don't think there's alot of data in that configuration...most 4bbl intakes are equipped with an elbow and single TB

what I don't like about it is that the "hat" is usually pretty sharp and air don't like to turn.

 

I understand air doesn't like to turn. But what I am wondering is if the 4 blade holes in the carb style TB and possibly the use of a 4 hole spacer underneath it helps to direct the airflow more than an open elbow does?

 

Lots of questions and few answers.

But regardless of intake, any boosted engine is still going to make loads of power. Of that there is no doubt.


And to the person saying Edelbrock have done a test vs the LS1 intake. n/a and boost are different.

Ive yet to see any proper testing on a boosted application.


I had thought about the 4bbl throttle bodies too, and they do look cool. Also thought about the addition of a 4 hole spacer. Probably make hardly any difference.

A big top hat on top of the carb intake might work better to even out airflow, simply by adding a lot of volume before any turns.

 

actually the bonnet on a 4 hole throttle body helps alot. The airflow is straightened pretty good by the tb. A 3'' 4 hole spacer under the elbow helps alot too-neither eliminate the problem but both help.

 

the testing has been done-it's just not public information.

Yes any intake will make good power, but an intake with proper distribution will allow you to lean on the tune up much more,also each cylinder will be pulling an equal load instead of half the cylinders doing all the work.

I see some guys at the track that got 20% fuel correction in certain cylinders. I'm like WTF-their comment is "well the air fuel is right in all the cylinders what is the problem?" They don't realize that the cylinders with 20% more fule are also making 20% more power-the rest of the cylinders are make 20% LESS power.

 

With the minimal difference in height, why isn't a 4 barrel TB and carb hat used more often? Why is this option not recommended more by engine builders/tuners if it helps?

Just asking...

 

Only "tests" I've seen:

1. High 8 second 347ci went from LS6 to FAST and gained zero in the 1/4.

2. 4xx car went from FAST to Wilson and gained zero in the 1/4.

Both LS1 style heads...between 15-20psi...7200ish max rpm.

Hard to beat a stock manifold under 25ish psi under 7200ishrpm IMHO.

 

I can only assume that if testing has been done, and no results revealed. Either the results are astonishing, or totally ****.

If a manufacturer wants to push a product, then they need to have the results from any tests published and out there for potential buyers to see.

I can only guess that the lack of public info must mean their products are crap then ?

 

I do not, but we read the plugs REGULARLY... ZERO issues here, and the main use for my car is Mile+; my car was built to be beaten on as much as possible, street or track it doesn't ever get driven easy... like I said we have to agree to disagree (on my setup) can't speak for anyone else...

 

there is actually a good bit of difference in height.

The other problem is the monkey see monkey do syndrome.
If somebody doesn't see 20 other people using something it must not work.

 

most testing isn't done by manufacturers,it's done by shops.

We test tons of stuff on both the engine dyno and chassis dyno. Alot of the info we keep for our own personal knowledge. There are plenty of others that do the same.

 

Hi Stevieturbo,

Yes I agree. If Edelbrock or no one else will publish the side by side Dyno charts on a pro flo Xt vs a LS6 intake or fast on the same modified motor then they must be trying to hide something. This would be a huge selling point if it beats the LS6 manifold across the powerband and not just at peak HP for a 30Hp gain. Otherwise these manifolds would be beating the heck out of fast manifolds in sales because they are so much cheaper and supposedly perform that much better. I am guessing it must be losing a bit of torque at low and medium RPM's.

As far as intake manifold performance N/A vs boosted for the HP and torque dyno power curves, they are generally at the same RPMs's whether boosted or not. Max torque and HP when they occur, peak etc. Actually the boosted truck manifold for example tends to extend the power band a little on the high end, otherwise it follows the same naturally aspirated low end torquey power curve. N/A vs Boosted intake manifold performance on the same intake manifolds have been dyno tested on many many dyno pulls in Richard Holdeners 2 books on n/a and boosted motors "DYNO -PROVEN GM LS1 THRU LS7 PERFORMANCE PARTS" AND "DYNO PROVEN 5.0L FORD DYNO TESTS. All these tests show the intake manifold intake runner length design primarily and secondarily in importance the cam on a fuel injected motor determines the power band of when peak Hp and torque occur whether boosted or not. And at a higher level of tuning Shawn at VA speed is right on correct about A/F ratio distribution being very important for each intake runner and overall intake design.

The silence on the performance of these manifolds that several have already asked about in this forum and others is deafening. I have been asking for 2 years and have yet to see any side by side dyno pulls of the pro flo XT vs the LS6 or fast intake. I wonder if Holley will be as silent as well.

Hpbob1

 

I was just going to say the same thing...you beat me to it.... Anyway, Shawn is right, I am sure most shops do test all kind of different parts, intakes, cams, heads...etc..that costs money to do and they arent going to give up that info for free. I dont blame them either. Thats how shops make a living..building stuff for customers that kick *** because of their R&D and time and money they have into it.... If they told all their secrets, they wouldnt have a job...I know from experience that it takes alot of years and alot of money to figure out what works and what doesnt, cant expect these guys to give out that info for free... We are lucky that they help us as much as they do for free...... just my .02

 

shawn is developing a special carb intake elbow that has alot of engineering to help distribution for my new motor...its so secret that I don't even know the details of what he's doing