what are the best exhaust pipe diameters for a NA car?
 

from the cat back I should say.

I do not want to loose andy torque and the car is stock except Bonez superflow cat and cone filter.

Mike

2.25 or 2.5 is the norm i think

I am going to move this to 2nd gen tech forum....

The Mindtrain system that I put on my car has 2-1/2" pipes in the cat-back portion, but I believe that the silencers in them are 2" cores.

There is no loss of torque, in fact it has increased if anything! This is in conjuction with a full exhaust header and cat removal (replaced with silencers), stock mufflers.

I really like the sound of this system :cool:

so are the pipes just 2 1/2 from cat to the back mufflers?

I guess the pipe splits immediately at the point where is bolts on behind the cat right?

I just replaced stock cat with a Bonez superflow cat/silencer system. Now I am going to work on the back half.

any one else got info. I will search some more.

I am still looking for the thread with the coupon for JCWhitney discount.

MZ

it depends on where you want your torque peak to be really. theres a calculation you can make with piston motors for optimum flow capacity, but im not sure about rotaries...? try to imagine 1.3 liters at 7000 rpm? prolly closer to 2.25 would be optimum