V8er

iTrader: (2)

Would a custom, mandrel bent dual 2.25" exhaust system with a low-restriction muffler be to too restrictive for a 450hp LS1? This would be combined with good LT headers. Would going to dual 2.5" make more power?

cyphur

iTrader: (10)

I'd go with at least 2.5", 3" if you're plannin anything more then 450.

NLang

iTrader: (12)

What he said...2.25 just ain't going to cut it...

Casperws6

LS1LT1

iTrader: (16)

I agree, 2.5" minimum.

How about on a bolt on only car? I still wouldn't use 2.25" tubing/Y pipe but what about 2.5" versus 3" as far as ultimate flow/efficiency/power is concerned?
I'm thinking that 2.5" might be better on a lower powered, NA bolt on car.

cyphur

iTrader: (10)

I agree with you. Sticking with just bolt ons, 3" may be too much. Hence why I suggested 2.5 unless he plans to surpass 450rwhp. At that point, a 3" exhaust is almost mandatory in my eyes.

GM Muscle

iTrader: (9)

I would go 3" so when you decide to make more power you won't have to buy another set up. My 2.5" system cost me atleast 3 tenths in the quarter vs open headers. I probrably make a touch over 500hp at the wheels.

777

iTrader: (21)

i was told that 2.5" is fine for quite a bit of hp...but i guess i was wrong...

V8er

iTrader: (2)

I would say 2.5" is good for lots of power but I am wondering about 2.25". Has anyone seen poor results in the 400+rwhp range by using 2.25" tubing? I know most people use 2.5" or larger but that doesn't necessarily mean it is required.

NLang

iTrader: (12)

Why bother going through the PITA of building/routing a 2.25 system now, and then have to do it all over again later on down the road with 2.5 if you decided to go for more pwr? It just wouldn't make any sense to do 2.25. Especially cost wise...There's no plus here...
I've built two different style 2.5" dual X-pipe systems (one with side exits before the tires, and one over the axle), and then went for 3" dual X, also over the axle (current). I've done a good bit of fab work in my days. Even with all the experience, if you wan't it done right, it is a pain in the *** job. Trust me, do it right the first time...

2MuchRiceMakesMeSick

Who stops at 450hp? I choose 3" cause I knew as soon as I got to 400, id want 500 then 600 then 700...you get the point...

nuzee

iTrader: (2)

Scroll down to the table on the following link:

http://www.dynomax.com/techsupport.stm#TechTips

z98

That chart is way off.

A single 2 1/2" pipe will support upwards of 350 HP.

Of course, this is actual experience talking, not concrete marketing hype.

LS1LT1

iTrader: (16)

I'm fortunate enough to be able to exercise some restraint when it comes to modding a car...I can say with some certainty that I will stop at a given point (in this case, bolt ons only) and I think I can stick to it, maybe.

cyphur

iTrader: (10)

Well I'm glad someone can. I know I can't, at least not with the fact that turbos are gettin a little easier to put on an LS1. I'd love to have twins on a fully built motor.

And someday I will, barring any catastrophic events in my future. LOL.

2MuchRiceMakesMeSick

Hahaha, so you claim now. Racing is addictive. When you first get your car your like AWW ITS FAST then later its not so fast anymore. Then you put some mods on again and its fast again but soon later is not fast anymore. Its a vicious cycle.

NLang

iTrader: (12)

Not only that, it's a great alternative to marriage...

LS1LT1

iTrader: (16)

I will fight it then, I will resist the temptations of the horsepower, I must remain victorious over the modding bug!


Now that is VERY true.

2MuchRiceMakesMeSick

Well Ill just say, when I first bought my car. I had no intentions of making it faster. Going from a old 4 banger to a LS1 was quite a setup up I must say. After a month later I had a lid and look at the car now. I just made my 6th payment on it.

Stark

iTrader: (25)

I must agree with 2Much.
I put headers and true duals on LAST week.
I am now looking at cams.
The mod bug WILL get you.