Hi.

just curious at the moment. but what would you guys recommend for a ls2 or ls3 swap? dual 3 or 2.5" or single 2.5 or 3"? custom of course

 

a single 3" gets you past 400hp before it's a restriction... dual 2.5" gets you well past 500hp.. an X pipe raises that a bit farther..

the 707hp Dodge Hellcats have dual 2.75" exhaust- and that's with mufflers that are likely designed to be cheap to make first, quiet and unoffensive second, and make power third...

 

thanks for the quick answer. sounds better to go with 2.5" dual with an x-pipe to be safe then

 

Single 3" is good for like 400hp as above, single 4" is easier to route vs duals and will support as much as dual 3" or 600hp easily. Remember the more pipes you add or the increase in size will affect noise, throttle/low end performance and peak power. The goal is to use a size that's less restrictive but meets the goals of the combo including your personal sound preference and tone. You can run a single 3" for more than 400hp but it will limit top end breathing but will increase low end performance. It's a toss up but exhaust systems need to be designed and not just thrown together. More than likely you need to plan it all out and what the overall goal of the project is and intended HP, rpm range and taste.

Personally i went from a walker replacement exhaust with a lightly modded 350tpi to true dual 3" with dumps on a HSR383 and then dual 3" to bumper with a 521 all the way back to my now supercharged 5.3 LS which I'm going to run single 4" for max clearance. All my dual exhausts ran 3" xpipes which helped with noise and all flowed enough for 600hp. You will loose a bit of low end with dual 3" on anything less or around 400hp it's just too much pipe and velocities slow down. If you plan on being around 400-450hp a single 3" is your best bet and the cheapest easiest option to run and fabricate with lots of clearance. Duals are not as easy to run and fab but can be done. If your planning to be around 500hp I would then step up to single 3.5" and anything like 550-600hp I would go with single 4". You can push a smaller exhaust size for much higher than the intended HP range but it will limit HP as the Rpms increase by choking it when it needs the flow.

Make an informed decision! Duals are not needed on these cars for the most part. If your pushing more than what a single 4" can provide then you prob got bigger issues and aren't running full length exhaust anyways. 4" pipe is enormous when u see it in person.

 

Have you looked through this thread?
https://www.thirdgen.org/forums/exha...l-exhaust.html