Which exhaust will give the best performance on a 96 5 sp 215 hp CC 4x4, a straight pipe 4" or 5" system? It'll probably have a 10 plate, GSK, BHAF, and a 62/12, so the turbo will have a 4" outlet. Which will give the best power, torque, spool up, and fuel mileage?

 

a 4'' is plenty rember the bigger you go the more drone you will have

 

I have had both and there was no noticable difference in power, milage, or any other performance aspect. There was a difference in sound like olddogetruck said there is alot more drone with the five inch. Sometimes i wish i still had the 4 inch. Very nice sound. Hope this helps.

 

It has been reported in old posts that unless your turbo has a 5" outlet (IE compounds) you are best sticking with a 4" pipe. The 4" pipe flows better than the 5" for the HP and exhaust flow required. I remember reading some guys loosing HP on the dyno with 5" vs 4".. Too much pipe diameter causes the exhaust flow to become turbulent and doesn't flow as well.

 

Thanks for the input guys, I've had 4" on firstgens before, but not 5". I was only thinking 5" because of the 4" outlet on the turbo. I can't find a 5" stainless system anyway, so 4" it probably is.

 

not to hijack, but would a 5" shorty exhaust straight piped into 6"x20" tip be absoluteley positively loudest exhaust possible? I don't mind drone

thanks

 

I think my 4" was louder than the 5". but if you want noise go with a stack. just put my singer 7" grandrock on yeasterday and it sounds pretty good.

 

go with 5 i love the drone cant wait till i put 5 in on this summer

 

the drone is not bad with the stock turbo. once i put an aftermarket turbo on with a 4'' outlet. the drone got worse. then i put a set of 6'' stacks in and i had to wear earplugs on the highway because my ears would be ringing. once i put on the twins it totaly went away. to me the cost of the twins was worth it just to get rid of the drone.