AE92 DIY exhaust

[molex]

I'm going to build an exhaust for my 20v AE92 Levin, at this stage going to stick with the factory 4/2/1 section so not particularly complex.

Anyone have any recommendations for 2 1/4" vs 2 1/2" on an NA 4a? Not interested in loud, happy to put in muffler/reso and will have the cat intact.

I need some bends, length of straight, a resonator and muffler for less than astronomical amounts of money.

Anybody able to help?

[QikStarlie]

2.5. good reso up front bit after collector -> big chambered muffler at back, inlet/outlet size or 2 bigger than pipe, as very unlikely will flow as much as the pipe -> decent length pipe after muffler, will help quieten it down.

[headshotnz]

I would go with the 2 1/4 personally, these engines require alot of back pressure. or even step up to 2 1/2 just before the back wheels.

[QikStarlie]

these engines require alot of back pressure.

[Bling]

Pretty sure factory is 2 1/4"? That should do the trick.

[ch4ng]

2 1/4" is factory on ae111 blacktops

[Burning Angel]

these engines require alot of back pressure.

agreed(with the facepalm)
there's no such thing as an engine needing "back pressure", any thing after the merge into 1 is a restriction an has no beneficial purpose.

[strx7]

the length of exhaust after the first flow interupter (cat/muffler/resonator) has the biggest factor on how droney it is. think about this when building it.

i'd go with 2 1/4 inch, and 1 x 3 chamber type muffler in the back with NO increase in tip size.

[solitaire]

the length of exhaust after the first flow interupter (cat/muffler/resonator) has the biggest factor on how droney it is. think about this when building it.

Good tip, so the shorter the less droney? or vice versa?

[strx7]

the length of exhaust after the first flow interupter (cat/muffler/resonator) has the biggest factor on how droney it is. think about this when building it.

Good tip, so the shorter the less droney? or vice versa?

yip, if you have a muffler in the middle of the car, it will be droney, for vehicles that have a cat or muffler right up the front, its going to be VERY droney

[QikStarlie]

these engines require alot of back pressure.

agreed(with the facepalm)
there's no such thing as an engine needing "back pressure", any thing after the merge into 1 is a restriction an has no beneficial purpose.

^ this. after collector inc some pipe length after the actual merge, no exhaust is best. thats not just for peak power either. so dumping into a large diameter pipe after "tuned" length & diameter . then using rest of the system just to quieten it down with zero restriction is the way to go. although will benefit something with aggressive cams alot more than a standard blacktop.