What is the going power restrictions for which size of exhaust system,

I'm looking to do the system on the fiesta soon and want to keep it as small and compact as possible for my power but obviously not restrictive

So what is the maximum for 3" an 3.5" systems?

My bench dyno was 540ish with 495lb/ft roughly

Thanks
Marc

 

hi mark 3 inch should be fine for your power level , just remember to get some biggish silencers in there , great car and its looking fantastic
keep up the good work

cheers paul

 

Thanks Paul

3" is what I was Hoping would be fine,

Does anybody know when 3" gets restrictive?

 

ive seen 3'' do 700hp .i wouldnt want to push more than that

 

hi
is that on a 4 cylinder engine

mark

 

i run a 3" on my r33 gtr at approx 650 hp, but rapidcossie had a 4" fitted to his 550 hp yb saph and iirc he had good gains just from changeing the exhaust from 3" to 4".

 

so did sean bicknell

 

I'm sure rapidcossies one was bigger at the turbo then stepped down in size towards the end, there was more to it than just going bigger.

 

Ran 740bhp on 3" but its was restricting the Power would guess 680bhp as a max to be safe. The 3.5" is still ok at 900bhp the most we have tried.

 

Not a chance the first 200mph run was on a 3" exhaust.

 

theres no debate rod, iirc he had back to back dyno runs from ava and he gained some power with the new exhaust.

im not saying 3" wont do it but there are free gains to me made from going bigger.

 

Sorry scoooby slayer, as a regular observer of many threads on this forum I can politely inform you that Rod has spoken and therefore you are talking crap, oh and your car is probably really really slow. You were right about the 'no debate' bit though!!

 

This is what happened to Euans car when AVA got rid of a 3" Magnex for their own system, 4" down pipe and twin 3" system IIRC.

 

lol

yeah thats what i remembered i just couldnt be arsed to go find the proof lol
cheers

 

bigger is better with turbo's for sure, i ran a 3" from turbo all the way back and felt fine at 2BAR, peak at 2.2 BAR on the gt3071r, so many feel 650-700bhp is the limit, although a 4" will be even less restrictive, or twin 3" pipes. it really comes down to space and ground clearance i'd think.

 

You know it only by testing. However, downpipe should be slightly larger than the rest of the exhaust system.

 

Warren & Wenny both run 4" down pipes that split off into 2x2.5" systems all the way to the back box.