exhaust diameter question

[projectPONY]

Wondering at what hp level one should consider an exhaust upgrade from the typical 2.5". I know this topic can be very debatable, so I'm just looking for a general consensus amongst us on the board.

I'm having a Dart based 363 built and while my 425-450rwhp goals are probably modest for most I'm trying to find out if I need to upgrade my exhaust.

TIA

[LS1Goat]

for that^ engine build, go 3" not 2.5".

starting in '05 the mustangs came from the factory with 2.5" with 300 hp. chunking that crimped 2.25" exhaust in the trash was one of the first things i did on my '00 gt. increasing pipe diameter will reduce velocity, but will not be an issue for the motor you're proposing.

[rusty shackleford]

Wondering at what hp level one should consider an exhaust upgrade from the typical 2.5". I know this topic can be very debatable, so I'm just looking for a general consensus amongst us on the board.

I'm having a Dart based 363 built and while my 425-450rwhp goals are probably modest for most I'm trying to find out if I need to upgrade my exhaust.

TIA

for that power level you are ok with 2.5" MANDREL bent piping. you won't gain much going to 3" as long as you have good flowing mufflers (not flowmaster). if you have flowmaster then you are going to need 3" mufflers.

[greenbullitt]

2.5 for that power level

[projectPONY]

So far so good then. Was really not wanting to upgrade anything unless I would gain hp. BTW, current set up is ceramic coated MAC longtubes 1 5/8 primaries with 2.5" collector. Off road H pipe and dumped after the flows. I plan on running tailpipes with new setup.

[Z06killinsbf]

I think there is power to be gained upgrading the pipes. Bigger headers would help some too.

[Cooter]

hell yeah, you could pick up as much as 4hp

[projectPONY]

I think there is power to be gained upgrading the pipes. Bigger headers would help some too.

I know someone selling a set of longtubes 1 5/8 primaries with 3" collector. I could go with a 3" cat back. I'm just saying cus the next larger size primary headers are expensive.

[Grape]

We make 230 with a 2-1/8" tailpipe with muffler...

[sickpony]

maybe 3 inch for a big block. Sounds like a pretty good little combo but unless you just want to make it raunchy loud 2.5 is good. Compression?

[Baron Von Crowder]

hell yeah, you could pick up as much as 4hp

Power gains reaching deep into the single digits!!!

[TENGRAM]

I'm having a Dart based 363 built and while my 425-450rwhp goals are probably modest for most I'm trying to find out if I need to upgrade my exhaust.

TIA

The engine builder should provide you with that info.

[projectPONY]

maybe 3 inch for a big block. Sounds like a pretty good little combo but unless you just want to make it raunchy loud 2.5 is good. Compression?

compression goal is around 10.5:1, trying to keep it on pump gas.

[projectPONY]

The engine builder should provide you with that info.

good point, I'll check with them.

[turbostang]

For the setup you mention, I can almost 100% gaurantee you it will LOSE power with 3" exhaust.

It will actually gain midrange torque with full exhaust and tailpipes.

MY own car, about 8 years ago ran consistent 8.1's with 2.5" flowmasters and no tail pipes. Only added tail pipes and instantly went 7.9's. (adding tail pipes is similar backpressure-wise to 2.5" over 3")