What Size Exhaust Pipes Work Best?

***Ed Blown Vert*** · 06-19-2014, 02:20 AM

Proper exhaust-pipe size is a function of both engine output and displacement.
Proper exhaust-pipe size is a function of both engine output and displacement. The higher the engineâ

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**2002ssslp** · 06-19-2014, 05:54 AM

I think 3" works best.

**Whamhammer** · 07-04-2014, 07:59 AM

Originally Posted by 2002ssslp

I think 3" works best.

I was thinking that too. I haven't seen too many 3.5" systems offered out there, and being that a stock LS1 is a bolt on or two from being easily capable of exceeding 350 hp...

**pajeff02** · 07-07-2014, 02:11 AM

Honestly couldn't tell you the diameter of my exhaust without going out and measuring it.

**Firebirdjones** · 07-07-2014, 05:40 AM

Originally Posted by Whamhammer

I was thinking that too. I haven't seen too many 3.5" systems offered out there, and being that a stock LS1 is a bolt on or two from being easily capable of exceeding 350 hp...

Keep in mind that graph doesn't specify but I take it as most likely crank HP and not at the wheels. So those pipe recommendations are very mild. Notice even for the 350 ci it's showing at least 3" and up to 4" pipe diameter for the single catbacks, and up to 3" for a dual system.

A stock LS1 on an engine dyno with no accessories floats very close to the 400hp mark at the crank. So the 3" single catbacks, while they work very well, are still a restriction. These cars even in stock form always make considerable gains from a dual 2 1/2" or dual 3" system.
They do make 3 1/2" and 4" single catbacks as well, Mufflex has been making those for many years, and they are shown to make measurable gains over the 3" catback units on even very mild and even stock combinations. There were alot of dyno sessions on it back in the day.