stock exhaust vs. modded exhaust nitrous sys.

[Only4U]

say a 75 shot:

what kind of difference is a COMPLETELY modded exhaust sys going to make over the stock exhaust?

thx

[pgriffith]

stock exhaust is way to restrictive for a 75 shot. I was running a flowmaster rear section with the stock I pipe, cats, s pipe and 2.5 inch tailpipes. It was still not enough. Now I have 3 inch mandrel bent all the way with flowmaster muffler and 3 inch tails. My nitrous hit 10 times harder after I did this. I would highly reccommend a good exhaust system for any nitrous application. Intake helps alot too.

[12secondv6]

I can't give you dyno proven rwhp and rwtq or even guarenteed et reductions but I can say this every where I have read up on nitrous systems they always say that one of the best ways to maximize a nitrous system is a full exhaust system.
think about this...... nitrous add's a lot of oxygen into the engine, how the hell would you get it out??? Stock will work fine, modified will work much better :D

[Arctc Wolf]

if you're gonna spray, get a bigger exhaust, especially if you already have intake mods. a 100 shot will get you up into the ls1 power range, so at least get 2.75" pipes like the ls1's do, if not a 3".

[12secondv6]

I've got 2.5 inch all the way past my s pipe

[pgriffith]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
I've got 2.5 inch all the way past my s pipe<hr></blockquote>

Have you ever thought about going bigger? I remember you were running a very large shot. 2.5 inch is not that big. Maybe even you would see faster times with a nice 3 inch setup or maybe even a cutout??????

[12secondv6]

Cut out open 282 rwhp and 335 rwtq
Cut out closed 291 rwhp and 362 rwtq
We are talking 10 rwhp and 30 rwtq lost when the cut out cap was taken off and muffler bypassed
As for 3 inch, I don't think so due to the above

[pgriffith]

was the 291RWHP with nitrous? How much?

[RaVeN1469]

12sec, what do you figure caused the power loss with the cutout? Loss of backpressure? Has anyone dynoed open and closed cutout without nitrous, maybe it's a nitrous thing. Well that just confuses me. Maybe a 3" exhaust would run better than 2.5 or open exhaust, who knows.

[Arctc Wolf]

as exhaust temperatures drop, the exhaust loses some of it's velocity, slowing down how fast it gets out of the car and how much pipe it takes up. the cut-out allows colder outside air to cool the exhaust quicker, causing mroe packpressure in the exhaust. This is just a theory of mine, so I may be wrong. When I eventually get headers and a bigger cat, I'm gonna get them jet-coated inside and out to help lower underhood temps and keep exhaust velocity up. If this doesn't help very much, I'll put on header wrap as well.

[12secondv6]

Yes it was a juiced run.
I still stand by saying 2.5 inch exhaust is fine on our cars up to the s pipe, then 3 inch.
It is all about back pressure.
I still haven't drilled and tapped some psi guages in my exhaust to prove it but one day when i am bored I will.
Our cars need back pressure

[Andy]

Whats up James? long time no hear from... heheheh

I been away trying to get school and work in line. Back in the game and looking to try and get some better times out of the 38S.

What exactly is a s-pipe? I want a cut out but I dont know where would be the BEST place to put it for spraying.

Also working on my new site with additional install help for the newbies.

[m.malloy]

so james are you saying that you have a 3inch cat and s-pipe, but a 2.5 i- pipe..

[12secondv6]

Headers
2.5 inch y pipe
2.5 inch cat in and out
2.5 inch I pipe
2.5 inch s pipe
3 inch cut out
3 inch cat back.

I'm not a fan of the cut out, I lost power. I do not suggest a cut out for anyone.

[pgriffith]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
Headers
2.5 inch y pipe
2.5 inch cat in and out
2.5 inch I pipe
2.5 inch s pipe
3 inch cut out
3 inch cat back.

I'm not a fan of the cut out, I lost power. I do not suggest a cut out for anyone.<hr></blockquote>

Im confused, is the I pipe 3 inch or 2.5? You state that its a 3 inch cat back with a 2.5 inch I pipe? So which is it?