Exhaust Piping Size?
 

Hey Guys,

Does anyone know what piping size should be used for a aftermarket exhaust? I plan on going custom straight pipes. I'm not to familiar with NA/RWD exhaust piping coming from Turbo/AWD.

Thank!

-Jonny

Haha, great question. If I were doing this I'd go with 3" all the way back....

Yeah I was thinking 3" all the way too. Thanks!

#" will be good but we need cobb or some one to get a tune out for this as we will gain HP but we are going to loose TQ this way.

Why would you do a 3" exhaust on a naturally aspirated VQ engine? I can guarantee you that gains will be non-existent. The only time I have ever seen any G/Z use such a large diameter piping is when they are going turbo'd.

Stick to 2.5".

^^^ +1 Exactly!

The car doesn't have enough torque as it is... The motor is likely already flowing exhaust as best it can as is... The same amount of air is going to flow out 3" as it would flow out a 2.5". And with 3" you lose torque because you're losing back-pressure. The only time you need to open up the exhaust is when you have MORE air coming in than can flow out at equal volume.

Thanks for the advice. As I stated I'm coming from a turbo awd car and don't really know much about exhaust size for N/A haha.

NP. You may WANT to turbo the Z later. The VQ37 is going to LOVE boost.