Pro speed stainless steel exhaust

[20Vcqdriver]

Have to recommend pipewerx. Ian Birch has also done extensive testing and told me a 2.5" system with properly mated 3" downpipe is good for 380bhp before any real issues... Above that he said go straight to 3" throughout..

[anthonys2]

ok thanks Jamo il bear that in mind when I start asking the necessary questions out of curiosity did you have your exhaust done by pro speed?

[Jamo]

No they've given me a great quote however, so have Pipewerxs

I need to get it sort asap really, but need to sort my hotside out 1st

[GazzaG60]

it may make 380. we did that with the subaru's on that size pipe. 350-360 seemed about peak though really. fitting a 3" gave about another 50 hp for free.

you are correct though the DP is by far the most important.

[Colesy]

Pro speed have also quoted me happy and I will probably end up going there when I've decided exactly what I want.

I've been talking to Rusty about exhausts and have been toying with the idea of an exhaust cut out valve. - Mainly because I don't want a loud car all the time.

I've found varying information on them though.

Some people mount them at the bottom of the downpipe and others after the cat. Some people rave about them others dismiss them completely, I'm just keen to see if anyone else on here knows much about them and whether they can give any advice.

I've been wondering if it would be a good idea to mount one just before the exhaust is restricted down from 3" to 2.5" to clear the rear axle? Ie just after the cat or just after the centre box. This way the standard exhaust can be quite tame and a little restricted (because of the 2.5"). But then if the ECV is opened up I'd essentially have a full 3" system which would be less restrictive so would increase performance and be louder.

Is this good theory?

Does anyone have any experiance of ECVs?

If so where would you put one?

[GazzaG60]

ECV's - put them in the bin.

why restrict the system. go 3" straight through. put extra boxes in to reduce the noise if you want to

[Rusty]

Pro speed have also quoted me happy and I will probably end up going there when I've decided exactly what I want.

I've been talking to Rusty about exhausts and have been toying with the idea of an exhaust cut out valve. - Mainly because I don't want a loud car all the time.

I've found varying information on them though.

Some people mount them at the bottom of the downpipe and others after the cat. Some people rave about them others dismiss them completely, I'm just keen to see if anyone else on here knows much about them and whether they can give any advice.

I've been wondering if it would be a good idea to mount one just before the exhaust is restricted down from 3" to 2.5" to clear the rear axle? Ie just after the cat or just after the centre box. This way the standard exhaust can be quite tame and a little restricted (because of the 2.5"). But then if the ECV is opened up I'd essentially have a full 3" system which would be less restrictive so would increase performance and be louder.

Is this good theory?

Does anyone have any experiance of ECVs?

If so where would you put one?

This is what I was thinking about, mount it under the rear seats.

Nice to have a car that's quiet for daily use but has a hooligan button.

[re2500]

2.5 is way too small for any real hp.

plus side is its way cheaper and most can bend 2.5

My CQ is running 300hp on not much more than an MTM ecu, and you could tell that before i had the pro-speed 2.5" exhaust the old 2.5" system was causing some restriction as it was a bit flat up top.

I recon that the exhaust i have would be fine for RS2 setup, and not be detrimental to the performance. Remember that my exhaust is single pipe un-restricted all the way to the rear diff. When i eventually get above that power to towards 400hp i will be fitting either a 2.75" or 3" down pipe but will be sticking with 2.5" from about the old centre box location back.

I would say a well designed de-cat 2.5" system is going to be fine up to about 350hp. Above that your probably throwing a few ponies away.

[Jamo]

Maybe in terms of dyno figures but a 2.5 inch system is giving serious back pressure above 270 bhp and is highly unhealthy for the engine.

[urS6Tom]

Maybe in terms of dyno figures but a 2.5 inch system is giving serious back pressure above 270 bhp and is highly unhealthy for the engine.

My car is actually booked into Prospeed this weekend.

I want something that won't restrict power (have RS2 setup with Scat rods), but doesn't sound like a boy-racer and doesn't drone on the motorway. I also need it to be able to pass the 95dB limit at certain tracks.

I'm going to go for a custom 3" turbo back system. Not sure yet whether to decat or 100cpi sport cat (probably decat).

The real choice is whether to taper down to 2.5" towards the rear to reduce drone, or put in a centre box

this is for a urS6

any advice welcome!

cheers,
Tom

[Jamo]

3" downpipe is essential you can then taper down post downpipe.

With some good boxes middle and back and a cat it shouldn't drone

[Rusty]

The gas will cool as it progresses along the pipes so a smaller diameter helps maintain gas velocity, as discussed, a little 2.5" should be OK for sub 400bhp so your setup (Tom) sounds ideal for this, if you go for more in the future then getting a 3" section really isn't an issue or expensive. I'd suggest that the cat is worth the money, passes the MOT and offers minimal restriction and some noise reduction over a de-cat, means that you can go less on teh back box so reduce post cat restriction that way. You won't notice or need a centre box with a cat and 2.5" drop as I found out

[re2500]

Charlie at prospeed is reluctant to do 3" over the rear diff due to lack of room. 3" Turbo back with a cat and 2.5" over the rear diff with just the rear silencer should be under 95dB Rusty has a similar setup and im sure his is.

Maybe in terms of dyno figures but a 2.5 inch system is giving serious back pressure above 270 bhp and is highly unhealthy for the engine.

Im going to have to disagree...Surely the fact that my ABY engine is running little more than a chipped ECU to increase power and it runs healthy above average BHP and good torque throughout the rev range means that it cant be restrictive, the turbo spools quickly and at low revs! 2.5" standard system with standard cats.... i agree. As it is quite badly designed and restrictive quite close to the turbo.

[Rusty]

Mine is quiet in the car, not much more than the Milltek and stock DP/cats.

Charlie likes to keep the pipe as close to the rear diff as possible to minimise bends and thus loss, if you were to bend a 3" pipe more than the 2.5" then you'll get it through, I'm sure he'd do it, just make sure that you agree with him what's required and acceppt that it might not be as tight as a 2.5" pipe. I was originally scepical but it's worked out well on my car. You won't need this trick on Avants or S4/S6 as it's a different routing to the coupe.

Mine was definitely stronger with the new exhaust and the VFM is superb over in the land of Wales

[Jamo]

Were you measuring you backpressure though Andy? Just because it felt good on 2.5 doesn't mean it was healthy or couldn't be improved.

In simple terms if you were chipped on homefries and changed to a 2.75 or 3" downpipe the car response was noticeable from the freeing of back pressure