Exhaust 2.5" 0r 3"

[desmo888]

The first few inches after the turbine housing are the most important - you could go 3" downpipe and 2.5 or 2.75 all the way back.


Pete.

This is also what I understand to be true. The dp sets up the speed of the gases exiting, after that it should be as free of restrictions as possible.

Be aware, many folks in "the business" think they know more than they actually do. I guess that could work both ways but from my rudimentary understanding of fluid flow, from the dp back, bigger is better.

[1975DCS]

Are there any "cheap" 3 inch (or 3.5 inch) exhaust ready available for an S2 Coupe? Or is everything limited or custom made? Previously I had cars fitted with Simons and they were simple steel, cheap and silent (I like that "stealth"), trouble is the 2.5 is not truly 2.5 in the dampers...

[Fat Audi 80]

I thought 3" was tricky over the rear axle on a coupe?

Cheers,

Steve

[K7ERG]

I went 3" results

Standard power 230bhp not sure on torque.

Power run 265bhp at 6500rpm @0.9bar and 250lb/ft at 4000rpm. Not bad as it is 15years old car which has covered 188000miles and standard apart from cone filter and 3" exhaust.

Revs better, smoother delivery and more power. If your thinking of more power in the future go 3" that way you buy one exhaust instead of 2.


Craig

[Jamo]

I thought 3" was tricky over the rear axle on a coupe?

Cheers,

Steve

Yes what they do is reduce it to 2.75 over the rear axle.

3" over the rear axle is possible but normally it knocks on every bump.

[Audi_CQ]

Yes what they do is reduce it to 2.75 over the rear axle.

3" over the rear axle is possible but normally it knocks on every bump.

3" is no problem and it doesn't knock on every bump It just take some time to get it right.

[BRY]

3" is no problem on an Avant

[Jamo]

3" is no problem and it doesn't knock on every bump It just take some time to get it right.

It does on an S2 as it catches on the rear diff.

2.75 is a much more elegant solution. It's not a issue either as the exhaust gas will have cooled enoughed by then that it doesn't become a bottleneck.

[1975DCS]

So that is why side exhausts are so popular again...
Group A style all over again!

[s2driveruk]

Longlife fitted a 2x2.5inch cat back on my 3b and said it would be fine to about 300bhp infact they said the most restrictive thing on the stock S2 exhaust was the Y at the bottom of the d/pipe and that was it.......

[Corey]

3" over the rear axle is possible but normally it knocks on every bump.

Depends whose system and how they fit it

Never had an issue with a 3" system it is just matter of time and patience

[blown_vr6]

Can they not ovalise the section where it goes over the rear axle Corey?

[Corey]

Can they not ovalise the section where it goes over the rear axle Corey?

There's no need, with the system we use it comes with V-Band clamps so once it is in place and aligned correctly the joints don't move and by using the hangers with the chains in them you end up with a no knock system.

[S2_Dave]

Corey fitted my 3" exhaust and I've not had a single knock.

[s2driveruk]

i've got those chain rubbers and they are a bu**er to get on but once they are the system doesn't move, they are fantastic