i was looking around for exhausts and i noticed that that the magnaflow Ti and the HKS are the only one's in 60mm (about 2.25 in) piping.the rest of the exhaust ar 80mm (3in)piping.now i was wondering it what would be best; buy something with 80mm piping and lose some low end torque, buy a 60mm piping set up,or get custom 2.5 in piping.i don't know if im planning to go turbo or not so ir some one could help me out,keeping that in mind.thanks

 

I wouldn't do 2.25 in, to small for me. 2.5" is great for N/A cars...and ok for Turbo cars. 3" Is kinda ok for N/A cars, and great for turbo cars.

The choice is yours, and yours alone. What would I do If I were you? 3" All the way

 

Same here man, well, since im buying a sr20det, yeah i would want the 3 inch. Just buy a good exhaust that is usable in both applications, maybe 2.5? just in case you change your mind and go turbo. That way you dont have to buy another exhaust.

 

Since you're undecided on the turbo thing, stick with 2.5" and a decent muffler... down the line if you do decide to go turbo, changing the piping to 3" should only cost you about $60-80 for a custom mandrel bent setup to replace the 2.5" piping you'd already have

 

It has been proven with dyno numbers that 3" exhaust on a NA 240 gives you gains in horsepower. I saw this on a thread in zilvia or 240sxforums. I tried to find it but couldn't. Anyways, the dyno showed around 10 more horsepower in the higher rpm's than stock. Makes sense considering the KA has a larger displacement than most imports on the road. High displacement=more fuel and air being used=more exhaust trying to escape. It would be loud as hell but worth it if you're planning on doing a swap anyway.

 

does anyone know wut the stock piping size is? everyone talks about 2.5, 3 etc, but how much of a jump from stock is it anyway?

 

IIRC, its 2.15" or 2.25

 

can you do 2.5" piping with a muffler that has a 2.25" inlet, or would you have to find a muffler that has a 2.5" inlet as well?

 

you can do 2.25 but it won't do you any favors. look for a 2.5

 

yeah... it all depends... what are you doing to your car? if you plan on turbo just go with 3"... I mean, it give you gains anyways, and you wouldn't have to change it in the future like they said ^.... 2.5" would be a nice little gain, and probably won't be as loud... but they're are always silencers if you don't like it... personally I went with 3" all the way, but I plan on turbo... but I did notice a difference with it along with intake.

 

I say 2.5" is the way to go

 

Ok Im keeping my engine and will not go turbo till next year or so. Or (got a mazda rx2 to work on) or maybe Ill never go tubo. Should I go with 2.5? What is the gain on a 2.5? is it alot less than a 3.0?