Alright I searched around for this for a while, but couldn't find any discussion on it.

car=1988 rx7 gxl n/a

would a 2.5 or 3 inch exhaust system be better for keeping the lowend torque aswell as getting high end hp aswell??

Ive heard 3 is better, but I was just more opinions to help the matter!

 

2.5" on n/a is the max size you wanna go.

 

Why stop at 2.5...if your trying to get the max power out of your car with no limitation...go three inch...for both turbo and n/a...will be better in the long run on the car...

 

No, teddy that is wrong.

The absolute maximum size for a non turbo would be a 2.5 inch, and generally you would be better off with a 2" to 2.25" (ID) exhaust for a non turbo. In fact HKS, builds their non turbo exhaust out of 50mm (ID) for maximum power. 50mm is actually just under 2 inches.

See with a non turbo, with too big of an exhaust the exhaust velocity slows down... so instead of the exhaust shooting out because of high velocity, it actually pools and swirls at most any bend or clamp.

If you had to go big, keep the pipe 2" until you get about 1 foot past the rear cat converter flange, then you can go up to a 2.5" ID. This provides the best low end torque, but still flows well on high engine speed.

 

Indeed, you would be retarted to go 3" on a n/a...

2.5 at the most, as said before.

I would recomend 2.25 if your planing on just BPU

 

If those are your choices, go with a 2.5" system. 2.25 seems to be a pretty common choice around these parts.

I'm saying this assuming that you're running close to stock... If you're running a massive port job, maybe you'll want something bigger. I'm guessing, though, that you're using a street car, not a racecar.

 

I'm running 2.25" with an extra long high flow resonator in place of the cats, magnaflow muffs and 3" tips...love the sound especially when I get up into the higher rpm range