best exhaust setup for stock bigport

[s13 james]

my 86 has a stock bigport with trd copy headers and ither 2.5 or 2.25 with a resonator and 1 muffler at the end,from the headers back is all munted now ie bashed up,2 holes,just rapped in genral haha,i was thinking bout getting 2.25 straight pipe from headers flange and straight out back,would this be way to go?noise etc dosent matter,from research people say 2.5 is good but slugish down low where as the 2.25 is a good compromise,also most swear under diff,but theres a few saying over and under is barely noticeable,leaning to going over diff as ill get stainless and dont wana fuck it on trailer,bumps etc unless theres a fair gain running under,i dont mind running a muffler,resonator if need be, after performance and would like it loud so im not drowned out by the sea of s13's haha

[meadan]

I reckon, small straight through muffler where the cat would normally go, then 2.25" all the way to the back.

Over diff if you can afford to pay for it, under diff if you want to save pennies...

I had this on my 20v, and it was plenty loud and seemed to go ok..

[s13 james]

that sounds alright,itd be good to loose the rear muffler as it hits on everything haha,keep the opinions comming

[slide86]

I would have the muffler as far back as you can........A single magnaflow offset muffler behind the diff will still allow max flow and give a nice sound too.

Id have a 2.5 inch from the collector to where the cat would be then into a 2.25 system from then on

[Konakid]

As above, but get a flatish muffler so it doesnt scrape and go over diff so you can tuck it nice and high up to the body.

[Ktas]

i used to run 2.25 off stock headers, cat, 1 resi, 1 muffler...

was definately quiet enough for street duty, but still punted some decent noise

i went under diff to try and keep it nice and straight, put a flange just before the diff, so you can drop the back off to work on the car/swap a straight 2.5 inch to the end

still had plenty of ground clearance the whole way through...

[s13 james]

so far im thinking what adan said
small straight through muffler where the cat would normally go, then 2.25" all the way to the back.

Over diff if you can afford to pay for it, under diff if you want to save pennies...

[meadan]

The flange just before the diff is a great idea too though, makes dropping the diff so much easier.

[s13 james]

so itd be headers,small straight through muffler where a cat would be,then a little b4 diff another flange and straight pipe out the back,so 3 sections,headers, mid section with a little straight through muffler,then straight out back,all in 2.25, can anyone see issues with this set up?will this retain back pressure?

[Jimmee1990]

Back pressure is bad, you're aiming to increase the air speed. Doing it all in 2.25 would be fine, I can't see you losing much low end if any at that size. I would always go over diff though, otherwise getting onto a trailer can be a pain.

[Rice86]

not being a JDM fag but spending money on an actual Japanese brand and design for a bolt-on to AE86 is worth the money for sound quality and performance gain..otherwise cheap and straight pipe will do lol

[lolwat]

Back pressure is bad, you're aiming to increase the air speed. Doing it all in 2.25 would be fine, I can't see you losing much low end if any at that size. I would always go over diff though, otherwise getting onto a trailer can be a pain.

you need the flow, having something too big will slow down gas speeds while having it to small will cause"back pressure" its all about the flow

[Jacobxxx]

Whats everyones reasoning for over diff? I went under for less bends and shit.

[lolwat]

longer path??? possibly help with noise?
I went under diff too, i dont see how height(getting on a trailer) would change with over or under diff

You can have a quality exhaust made in AUS, with out the "BRAND NAME" and half the coin

[s13 james]

bit of a update,picked up a stainless rsr 86 system this afternoon looks the bizz looking forward to first start and rev haha,gona start removing old system tomoz arvo,thanks for the help,bit of a fluke it poped up