TNT76

Well I've been getting a few parts together for my next engine and thought I'd flow the heads.

Here are the figures from a Superflow 600 at 28". With and Without the manifold bolted up. Without was with a radius of unknown size, as I wasn't there when it was done and the guy who did the testing wasn't in the shop when they were picked up. The manifold was port matched only and blended a couple of inches into the runner

............... Int Only.....Int+Manifold
0.050........35.4..........35.1
0.100........69.7..........69.7
0.150........109.8........94.8
0.200........147.5........132.6
0.250........185.9........182.4
0.300........223.6........218.3
0.350........253.6........244.7
0.400........273.2........264
0.450........294.6........281
0.500........307.9........291.9
0.550........320.8........301.3
0.600........331.5........311.1
0.650........338.2........311.1
0.700........332.4........315.1

Not sure why the difference between the two was so great at .150 and .200 and not so at .250?
Shows how much the intake lopes off air.

69LT1Bird

iTrader: (1)

One more column with an LS3 manifold would have been a good addition.

smok'nZ

iTrader: (160)

surprising i thought the lsxr would flow more btw these are stock heads and also were they the lightweight valves or heavy

mike c.

iTrader: (1)

We made no gain on the dyno going from a l76 to a fast intake for the l92 heads. I was excited to get one,then the dyno stopped all that.

PwrdbyLS1

iTrader: (5)

Stock L92 castings?

Here's my numbers for stock L92 & ported L92 with ported LS3 intake.

Stock #s ( I / E )
.100 75 56
.200 151 115
.300 214 155
.400 268 182
.500 294 202
.600 320 204

Ported #s ( I / E / LS3 I)
.100 70 56 73
.200 155 119 156
.300 230 172 222
.400 280 205 265
.500 320 228 290
.600 344 236 307
.650 352 238 312
.700 358 242 318

Fast 102 seems to choke less the intake port of I compared to my ported numbers.

jleews6

iTrader: (2)

I think it would be nice to see that same test run with a carbed intake.

tektrans

iTrader: (23)

FWIW, my L92's on my 441, not stock obviously-flowed 330 through a ported L76 intake. Don't have the flow #'s w/o the intake.

Cool comparison.

mike c.

iTrader: (1)

No. Ported stock l92's.

formula17

iTrader: (4)

What was that a response to? I wondered earlier if the original heads were ported or not im guess no based on the flow numbers. I believe the fast will make more hp everytime on the dyno or a stock L76/LS3.

69LT1Bird

iTrader: (1)

How do you figure and do you have any numbers to show the gain?

In this thread the FAST flowed 311 @ .600 and the ported/ported LS3 flowed 307, do you really think you will see 4 CFM?

formula17

iTrader: (4)

Those flow numbers on the OP's heads are un ported correct?? They would have to be. I would think if you took some NICELY ported L92's and then put the fast intake on it, You will see some different numbers. You cant compare ported LS3 heads and ported LS3 intake to a stock set of LS3 heads and a fast intake, Thats not an even comparison. On top of that these things were also flowed on two diff benches. Their are plenty of threads where this intake made around 15hp over a stock L76/LS3. Now their seems to be this buzz going around that the Fast 102 will not make anymore hp and in fact you might lose hp. I can understand people not wanting to buy it based on its cost, I wouldn't upgrade either if I already had a ported LS3, BUT don't be so ******* stupid to think its going to lose hp or make NOTHING over a stock LS3 or even a ported LS3 for that matter. Seems like the only people that knock the fast and repeat this bs are the ones that probably sleep with their wallet in their hands... IF someone wants to let me borrow there ported LS3 or stock LS3 when I take the car to the dyno, I Would be more then happy to do a back to back QUALITY comparison. IF I am wrong I will have no problem eating my words.

69LT1Bird

iTrader: (1)

On a big inch engine it will gain. On a 6.0-6.2L it may gain a minimal amount, not 15. I know I never said it would lose hp, so I hope you didn't direct it at me. When some of the biggest LSx vendors do not even try to push this intake that should tell you something right there. It is more like 4-5 hp gain over a ported LS3. There was 1 or 2 vendors who claimed 15hp, they have since gotten awful quiet.
Calling people "******* stupid" is just plain rude and not needed.

formula17

iTrader: (4)

I'm on board with everything you just said and agree 100%. When I said 15 hp I meant on a stock engine over a stock intake manifold. Why most vendors don't push the intake is they probably see who buy L92 heads...Which generally are budget minded people (Not everyone obviously, but the majority). Face it, they are cheap heads that make great power, But there are better heads out there. Those same people that bought the cheap heads, Usually aren't going to pop for a 12-1300$ intake throttle body combo, Expecially one that isn't making much more then a ported stocker. "******* stupid" maybe harsh and rude to some (not directed at you) but SOME people are thick headed and will regurgitate anything they hear on the internet. Hey we're both from Michigan we should have better things to do than bicker on the internet lol, Like making sure we keep our jobs, businesses, houses and most importantly our CARS.

69LT1Bird

iTrader: (1)

It's all good. You are right about the internet sheep, they will follow some people right off a cliff.

X10

smok'nZ

iTrader: (160)

i have a stock L76 if you want to pay for shipping i would let you borrow it but surely someone local to you has one laying around

TNT76

The whole idea of the thread was to show the difference between outright head flow and that with the fast bolted on, not to focus on the peak flow numbers.
I read somewhere where a 300 cfm cathedral port head was taken down to I think around 260 with a std ls6 manifold and around 275 or so with the fast 92.
My comparison was for the rectangular port with 102mm on, which shows a 20cfm drop at .600