So i've got a nice exhaust system under the fiero, cut trunk, blah blah blah its flowmaster. I want something louder and mean and of course not legal when revving because of sound. I was thinking of cherry bomb extreme one in to 2 out. Any recommendations on the diameter. Ive read that 2.5 inch can provide enough flow for up to 400hp which im not even close. But the smaller the pipe the better for top end and the larger the better for low end. The idea is to go from exhaust manifold to the cherry bomb and out, no resonator or such. Looking for some advice before I waist the money. Also I might list the current exhaust for sale once I get the other.

P.S. If I were rich i'd have a car that shakes building windows loose thats the sound I want .

[This message has been edited by timenewton (edited 02-13-2018).]

You'll get that loud with the extreme.

Someone did it:

*warning, F word twice



The smoke is likely the paint burning off, or unless he has another issue.

[This message has been edited by 2.5 (edited 02-13-2018).]

I saw that, I would not just be letting the muffler resonate fumes all up in the engine bay though, i'd be going out to tail pipes might sound alittle different I was just wondering if someone knew about back pressure. Would that be enough back pressure and such.... beyond my knowledge.

You don't need back pressure with a 3800. you never need or want it on a forced induction engine.
anyway and the few motors that actually benefit from back pressure usually come with small intake and exhaust manifolds and no better options for them.

From what i remember being told by my ancient mechanic:
The enlarging of the exhaust on those small old engines tends to create turbulence in the exhaust and slow the flow
depriving the engine of high rpm horsepower and some torque.

now days with ecms and such let it flow as fast as you can.

[This message has been edited by Strappado (edited 02-14-2018).]

Very informative video about back pressure.

https://www.youtube.com/watch?v=jjPeP_Nn2B4