2.50 exhaust piping on t28 equipped redtop

[KwKouki]

Im contemplating using 2.50 piping for my custom exhaust. Im looking for the optimal amount of backpressure/torque. My car will mainly be used as a autoX/track freak. From my readings, this size piping should give me what I need.

Any thoughts on this?

[Boostedrex]

It's fact that the bigger diameter exhaust you run, the faster you'll spool and the more top end power you'll have. No here's where I run out of info. In the rotary world, 3" exhaust, or bigger, is the standard for turbo cars. Anything less than that is going to hinder your performance. Hope that helped at least a little.

[ManoNegra]

Wondering why 2.5 and not the common 3" that everyone favors? Should be fine for stock or slight increase in hp.

[Irukandji]

smaller piping will give you slightly more low end torque, but just go with 3 inch piping. you'll have significantly better top end power with 3 inch.

[wootwoot]

^^^^ why will it give more low end torque? That statement is completely false.
More back pressure is more restriction on the turbo. In a turbo motor, the sooner you get boost the sooner you have tq. In a turbo motor, the less restriction the faster the turbo spools. Does nobody understand anything? Quit regurgitating bull shit and think. 2.5'' will give you less torque and less horsepower while making your turbo work harder.

[GlacierFreeze]

Originally Posted by wootwoot

^^^^ why will it give more low end torque? That statement is completely false.
More back pressure is more restriction on the turbo. In a turbo motor, the sooner you get boost the sooner you have tq. In a turbo motor, the less restriction the faster the turbo spools. Does nobody understand anything? Quit regurgitating bull shit and think. 2.5'' will give you less torque and less horsepower while making your turbo work harder.

+1 Miiiiillion

Hell, I've seen a dyno chart of someone's non-turbo KA with some measely intake pipe on it with a 3" exhaust. It made 12whp more than stock and NO loss in low end torque. I sometimes wonder why KA-T people don't use bigger than 3" exhaust hahaha.

[Boostedrex]

Ideally, you want to use as big of an exhaust as you can fit under the car. Many of the high horsepower RX-7 and Supra guys run 5" or bigger exhaust!! So on a turbo motor, I would never suggest anything smaller than 3". The more stress you can take off your turbo then happier it will be and the longer it will last.

Zach

[s13silvia123]

Originally Posted by Boostedrex

Ideally, you want to use as big of an exhaust as you can fit under the car. Many of the high horsepower RX-7 and Supra guys run 5" or bigger exhaust!! So on a turbo motor, I would never suggest anything smaller than 3". The more stress you can take off your turbo then happier it will be and the longer it will last.

Zach

true on what your saying. i wanna run a 4.5in piping exhaust system on mine but no one i know would sell it. i know costume exhaust but it would rust sooner or later i want it to last for a long time. i'm currently using my apex N1 but gotta get rid of it soon so i can get a new one cause i have some holes in the back of the canister. i'm losing torque. larger piping s are less restrictve on turbo charge cars.

[Boostedrex]

Custom exhausts will last just as long as any that you'll buy from a major company. Just make sure that the shop making your exhaust uses stainless steel. From the custom setups I have seen, people will run 4" out of the turbo to a 4" borla XR-1 (used as a midpipe) then on back to another 4" XR-1 for the muffler. It flows great and was even pretty quiet on a ported rotary.