# Dyno gains FAST 102 with exhaust on my LS1



## svede1212 (Nov 1, 2005)

Thought I'd post this up over here. I got some pulls Saturday on the same dyno as last year with the only differences being 91* this year, 83* last year and the FAST 102 w/Nick Williams 102 TB plus my custom exhaust. I was very happy in my gains of 15-20 RWHP and RWTQ across almost the entire band. 

Most I attribute to the 102 over my old LS6 manifold with a 80mm ported neck and TB. What was interesting to me was the low end gain. I've scoured around for different charts in a compatible HP range and FAST manifold. Mine gained really big down low I think doe to the exhaust I pieced together. 

After extensive exhaust theory reading I came up with 3" dia collector extensions bolted to my SLP LTs. That transitions into the SS 2.5" pipes of my Pypes "drive tunnel" X pipes. That allowed for a shorter effective collector than the long SLP 3" mid pipes that were on before. The total collector length is now 18". It also allows the X to move up closer to the collectors and not having to worry about putting the X after the factory mid connection point. To a point the closer the X the more effective it is. Those pipes then go to 2 Borla Pro XS mufflers in the '04 position flowing back into custom-bent aluminized pipes out to the stock '04 bumper cutout.

The exhaust gasses reach the collector where they are reflected and the negative pressure sound helps witrh scavenging. Without resonators or cats to tumble and damp out the exhaust pulses they feed into a X that is close to help in their scavenging better. The gases cool somewhat rapidly as they go back (you don't have 1,400* going out the tips). The smaller pipes keep the velocity up as the condensed gas doesn't need as large of pipe to move as much at the same speed. 

The Borlas were selected to replace my SpinTech Pro Streets as they are not only the quietest muffler of many tested but were the third in least amount of HP lost. "Quiet" is a relative term tho as with intake, heads, cam, LTs, !cats, etc she is still authoritative sounding.

432/394 and power all over. Over 300 RWTQ from 2,000 all the way up. A FAST doesn't add at the bottom so look at the 3 old pulls compared to the 3 new pulls with the new exhaust.


----------



## BWinc (Sep 21, 2005)

Not bad for a puny LS1 

I hope to hit those kind of numbers eventually.


----------



## Dishphead (Jan 4, 2012)

you say the borlas were third in least amount of hp lost. where did you find this kind of list? im interested


----------



## Razzle (Jul 12, 2012)

I will also have my dyno numbers wed. before and after my Fast 102 manifold.

Great numbers for a LS1. Way to go.


----------



## svede1212 (Nov 1, 2005)

BWinc said:


> Not bad for a puny LS1
> 
> I hope to hit those kind of numbers eventually.


lol. If you did the exact same mods you could expect to get 20-30 more HP out of your 18 ci advantage.



Dishphead said:


> you say the borlas were third in least amount of hp lost. where did you find this kind of list? im interested


Sorry it was 4th by 0.2 HP . What impressed me was how much they tamed my head/cam/LT car. It was loud and obnoxious with 4 mufflers at the same time (2 were Spintech, 2 were 22" glasspacks). It's smoother and quieter (but nasty at WOT) with a muffler that when you look at it figure it's not going to do much of anything.

Borla Pro XS












Razzle said:


> I will also have my dyno numbers wed. before and after my Fast 102 manifold.
> 
> Great numbers for a LS1. Way to go.


I'll be looking for your numbers. Make sure you list your power mods. If they have an overlay like I had it will be easier to see the gains too.


----------



## Razzle (Jul 12, 2012)

*346 RWHP, 341 RWTQ* with...

SLP 455 Bobcat Tune
K&N intake
JBA Shorty Header
JBA CatBack




*374 RWHP, 371 RWTQ* with...

+28 RWHP with the addition of...

_Fast 102 Manifold (Ported)
Underdrive Pulley
Catless Mids_


And trust me! That 28 RWHP was definitely felt!


----------



## svede1212 (Nov 1, 2005)

Nice gains! With your LS2 the gains are even better because the LS2 manifold sucks that bad. Looking at your graph your HP rolls over at a pretty low RPM. You need a cam in that thing so you can run her up higher.:cool

The reason RPM is important is gearing multiplies torque. That's why you can take off in first well but not so much in 4th. Because of that even when torque is dropping off at high RPM the torque is still higher in that lower gear than in a "better" part the next gear's torque band. The higher you can run it the more you're delivering higher torque and torque is acceleration.


----------



## Razzle (Jul 12, 2012)

svede1212 said:


> Nice gains! With your LS2 the gains are even better because the LS2 manifold sucks that bad. Looking at your graph your HP rolls over at a pretty low RPM. You need a cam in that thing so you can run her up higher.:cool
> 
> The reason RPM is important is gearing multiplies torque. That's why you can take off in first well but not so much in 4th. Because of that even when torque is dropping off at high RPM the torque is still higher in that lower gear than in a "better" part the next gear's torque band. The higher you can run it the more you're delivering higher torque and torque is acceleration.


Thanks a lot. The cam/head combo is my next mod. I found a C.A.R.B EO approved heads online and will be trying those out with a nice mild cam. Mild to hide from the smog tech.

And again thanks for clearing up that HP to RPM, I would have never known that.


----------



## danfigg (Sep 27, 2009)

*re*

Im assuming your base line when she was stock was around 300 hp. For every mod you did you picked up about 22 horsepower. Luckily you know how to use the HP tuners and have a good shop that did your exhaust. Now from your prospective, what do you think which mod made the most HP for you or does every thing just complement each other.----danfigg


----------



## svede1212 (Nov 1, 2005)

I know one mod compliments the other so that the total can be more than the "sum" of the parts. I'd say that the biggest single mod increase was the cam. I added 60-70 HP with that. That said it wouldn't have gained that much without the headers. Headers were the second most HP over a broad band. Doing something like cam and heads without the headers and exhaust would have netted considerably less.


----------

