Will RS2 oem exhaust be OK for 450 bhp ?

[macspring]

Just wanted to ask if the standard RS2 exhaust is too much of a "stangle point" for an B4 Avant with a K26/27 #6, with the rest of the parts that are normally upgraded changed.

I liked the idea of no additional noise over stock.

Miltek exhausts are not cheap, but BN pipes seems to be over twice the price of a Miltek, are they twice as good ?

Has anyone got a BN pipe fitted ? Any comments ?

http://www.bn-pipes.de/en/shop_audi_...m-aurs2ha.html

Thanks.

[Wrath]

Ive got BN-Pipe on mine and if you want no additional noise this system is nothing for you. Then a custom build system with large muffler is your alternative. But to answer your question , you dont need a bigger system then stock for that power output.

[Avantus]

Friend of mine has an RS2 with BN exhaust. Sounds VERY nice with no drone.
Not cheap however.

[Wrath]

I agree that it sounds very nice (have it myself) indeed but it has a higher exhaust sound then stock...

[Costash]

What can I say from my point of view also running k26/27 #6 hot side hybrid is, my 3.5'' downpipe halfway and 3'' after and joining standard system was a huge improvement on car reaction. You really feel the engine running more freely sort of speaking. I was going 3.5 just thinking on long run going more power, already replaced the standard part of exhaust left previously with full 3'' .

[A80Avant]

Just wanted to ask if the standard RS2 exhaust is too much of a "stangle point" for an B4 Avant with a K26/27 #6, with the rest of the parts that are normally upgraded changed.

I liked the idea of no additional noise over stock.

Miltek exhausts are not cheap, but BN pipes seems to be over twice the price of a Miltek, are they twice as good ?

Has anyone got a BN pipe fitted ? Any comments ?

http://www.bn-pipes.de/en/shop_audi_...m-aurs2ha.html

Thanks.

BN pipes and no drone???

Who ever said that?

Let me tell you. I had the milltek 3inch which created a drone around 3k rom so going on 6th and 70ish mph wasn't an option as there was too much noise. Nevertheless I did about 3k kms over europe with this setup and my wife and brother eventually got used to it.

Then I had an accident and bent the middle resonator so I did an exchange for a bn pipes one being assured that it makes less noise than my milltek!

So on it went for the rest of the trip.
Needless to say that I nearly got a beating from the rest of the group in the car for the extra drone we now got!!!
And of course once back in Greece I got a 2.75inch cat back and have it ever since without any drone issues. Nice burble and still rattles the windows of the apartment building on idle.

Either I'm used to not having earplugs for driving my car or every1 feels that its not enough noise off the exhaust

[prj]

A decatted exhaust could be OK, but I'd upgrade the downpipe to 3".

On my RS4 I run the U337600R middle box, and it is very good at killing the drone:
http://www.jetex.co.uk/website/custo...s&dia=3.0+inch

It is made by Simons www.simons.se.

I think it could work quite well on a S2/RS2 too. There are longer and shorter versions available too.

[driftin jo]

Ive got BN-Pipe on mine and if you want no additional noise this system is nothing for you. Then a custom build system with large muffler is your alternative. But to answer your question , you dont need a bigger system then stock for that power output.

That depends on how you look at it, you could make 450 on a stock RS2 exhaust but
it would not be optimal at all for that power level.

http://www.s2forum.com/forum/showpos...9&postcount=36

[Avantus]

A decatted exhaust could be OK, but I'd upgrade the downpipe to 3".

So a 26/27-6 is better of benefits from a 3" downpipe after all?

still in doubt for doing it or not.

[prj]

I mean, it depends on the turbo.
I am thinking OP is a bit optimistic of getting 450 out of a K26/K27. If it is a big K26/K27 and it will really make 450, then it would be beneficial.

If it is a usual K26/K27, which makes about 420hp, I don't really see the point in the effort.
Hell, I ran a K26/K27 on my C4 with the standard 2.5" down pipe and I didn't notice any really slow spool or tons of timing pull compared to the cars I've tuned later on the 3" exhausts with the same turbo.

But I think the difference will be a lot more noticeable going 2.5" to 3" than 2.75" to 3".
The K26/K27 turbos usually have a #6 housing, and the housing is so restrictive that there is a lot of backpressure in the exhaust manifold.
The hotside basically chokes the flow before the 2.75" downpipe does.

I'd say a GT3071R with a 0.82 A/R hotside would benefit a lot more from the bigger down pipe, as the diameter is flow related, and the K26/K27 won't run much more than 1.6 bar up top, whereas the turbos with the larger housings can go up to 1.8-2.0 bar where DP diameter becomes a problem.

[Avantus]

Ok thanks

[macspring]

Very interesting link, thanks.

I have a three inch down pipe, with two three inch two straight through boxes, and it is too loud and too far from factory noise levels, so I think, I'll need a three inch sports cat, and two medium length sausage shaped boxes, in tandem, after the sports cat and before the exhaust turns away from centre at the back of the rear passengers footwell, all to quieten the exhaust, but still keep it at three inch.

I presume no one has sought to obtain oem four inch boxes from some car to use on an ABY to have the flow and the quietness both at the same time. Sounds too hard and messy to do to be honest.

[macspring]

I mean, it depends on the turbo.
I am thinking OP is a bit optimistic of getting 450 out of a K26/K27. If it is a big K26/K27 and it will really make 450, then it would be beneficial.

If it is a usual K26/K27, which makes about 420hp, I don't really see the point in the effort.
Hell, I ran a K26/K27 on my C4 with the standard 2.5" down pipe and I didn't notice any really slow spool or tons of timing pull compared to the cars I've tuned later on the 3" exhausts with the same turbo.

But I think the difference will be a lot more noticeable going 2.5" to 3" than 2.75" to 3".
The K26/K27 turbos usually have a #6 housing, and the housing is so restrictive that there is a lot of backpressure in the exhaust manifold.
The hotside basically chokes the flow before the 2.75" downpipe does.

I'd say a GT3071R with a 0.82 A/R hotside would benefit a lot more from the bigger down pipe, as the diameter is flow related, and the K26/K27 won't run much more than 1.6 bar up top, whereas the turbos with the larger housings can go up to 1.8-2.0 bar where DP diameter becomes a problem.

Happy to agree re the 420 / 450 bhp from a 26/27 #6.

So in summary, am I correct to conclude, a 26/27 #6, or a GTX3071 .63, with a 3" inch down pipe and a oem 2.75" inch RS2 exhaust should do over 400bhp all day long, with reasonable spool up, given the "restriction" of the oem RS2 exhaust ?

Thanks.

[prj]

Happy to agree re the 420 / 450 bhp from a 26/27 #6.

So in summary, am I correct to conclude, a 26/27 #6, or a GTX3071 .63, with a 3" inch down pipe and a oem 2.75" inch RS2 exhaust should do over 400bhp all day long, with reasonable spool up, given the "restriction" of the oem RS2 exhaust ?

Thanks.

Well, I can't comment about the rest of the exhaust so much, but with those small turbine housings, I doubt you will really notice any change between 2.75" to 3" on the downpipe front.

[JP]

I had a straight through 3" system with 1 straight through centre box and 1straight through backbox. Drone drove me up the wall getting out the car with jaw ache on long journeys. So chopped the back box of and bodged a stock s6 backbox onto it and the car became silent with no drone and still made 575ponies.

I've gone a different route now as no longer a daily but the stock backbox served it's purpose for many a year.