2.75" V's 3" - what do you think?..

[europeanme]

having a failing cat to centre pipe joint I am having to look at replacing my exhaust.

It would seem rather foolish just to replace like for like... (I know this would make less of an impact on my depleting funds) but as it was always on the cards I have decided to take the hit now and get it sorted.

I am still un-sure what to do...do I go all out for a custom 3" system or go with a 2.75 supersprint DP/sport cat/hybrid system??....

I don't really plan taking the engine power over 350hp....even if I get that far!!...

I am just after a system that gives good flow and a rather nice sound more than anything else...

thanks for any advice/tips/abuse given...

Mike

[GazzaG60]

well mike if 350hp is the limit id go with the SS. it will be more subdued.

alternatively you could have a 2.75 or 2.5 inch system made. the sound is a lot quiter from experience.

JP exhaust used to make the systems for my mates old subaru company. with a filter and full system it gave an extra 60hp dyno proven. thats no cat though. i had one on my corrado too. great system. the 3" i have on the audi is superb too but maybe a bit loud.

id be tempted also to have a 3" to the rear axle and 2.5 or 2.75 from there. it wont be a restriction so far down the system

[Jamo]

3" isn't loud if you use the right boxes etc

If you want performance but want to dampen noise go for 3" downpipe and use twin pipped centre section. Slight loss in performance but you will kick yourself if you get 2.75

S2Avants car on stock RS2 map with 3" got 355 bhp vs the 315bhp of stock RS2 2.75 exhaust.

For me it really doesn't add up to go 2.75 unless you are staying stock.

[GazzaG60]

i thikn my header and no cat contributes to the noise. it aint quitet mine and the boom can be a pain at around 1800rpm.

i think loud is each to their own. i can be heard upto 1/2 a mile away by a mate with double glazing.

[europeanme]

I suspected the 3" would be the way.....but as has been mentioned it all depends on using the right boxes to control the sound....

any suggestions on boxes..or is a trip to OJZ worth a go??....

[Sonic]

Ive got the 2.75" milltek with sport-cat.

Sounds absolutely awesome when you press the loud pedal, very pleasant to drive down the motorway with and im hoping it will be good with a high RS2 spec, although i understand a 3" would give me slightly more performance.

If you're not going over 350bhp then a 2.75" will be fine and im sure you'd get tired of the 3" boom without the power to compliment it.

[europeanme]

If you're not going over 350bhp then a 2.75" will be fine and im sure you'd get tired of the 3" boom without the power to compliment it.

this is what I thought but as Jamo suggested get the boxes right and it shouldn't be a problem....

it's finding the right boxes first time round!!?!?!?...

[Jamo]

Well you could ask Andy Casey for a sound clip of his 3" exhaust he's just had done from Prospeed.

OJZ exhausts are a work of art

[Rusty]

My 3" is a 3" dp, sports cat and then 3" to the centre join (there's no box) then it's 2.5" to the custom rear box. Noise levels are low, a touch more than the Milltek ubt really not much. I would hope that this setup is suitable for about 400bhp, maybe more. It's a lot quieter than I thought and the fit and finish are very good.

[Error404]

by my calcs a 3" should flow about 20% better than a 2.75" so no contest really

Have you got a sound clip of yours Andy?

[lind4hl]

http://video.google.com/videoplay?docid=-8157798453606918513&ei=MoR4SdLUJZLQjwK7_fT2Dw&q=audi+s4+p%C3%A5+is=lMCoggueDgQ

AAN with 3" and 2 silencers.. ( no fuel in 2 corner, thats why it sounds weird)

[Rusty]

by my calcs a 3" should flow about 20% better than a 2.75" so no contest really

Have you got a sound clip of yours Andy?

I'll get one sorted out. It's really nice, with the windows up it's quiet enough except on WOT, with the wondow down it sounds awesome without being silly loud. Nice and sensible on a cruise but more power. Chuffed. If it was a dedicated toy car then a bit more noise would be nice but that's down to the cat really and as the rear box is custom made you could have it tailored. Dropping to 2.5" over the rear axle removes a lot of the resonance of a pure 3" system IMO and gives more clearance. The pipe is really straight so gas flow is not an issue.

[Error404]

Sounds ideal for a regularly used road/track weapon Andy

so is yours a twin box or single box system then? Did they ever make a jig for a proper 3" downpipe mate?

[T2Andy]

im really happy with my supersprint dp and custom exhaust lots better pickup\top end
power and sound

[A80Avant]

i have a 2.75(70mm) catback with twin boxes and im nowhere near 350hp. it is not loud at all(from the inside at least) and perfomancewise it is still very good.
When i had the remap i was using milltek's catback(3inch) and as soon as i went back home,i had that replaced with the 2.75 because i didnt like the loudness.To be honest,i never saw any difference in EGTs(meaning more backpressure) with the 2.75 catbcack and i cannot say that the custom made boxes were all that better than the milltek ones since overall my new system was quite more subtle than milltek's one.

However i am concidering now to go for a custom job of replacing the tubing to 3inch since i have future plans,but i will keep the boxes as they are.I may have some adaptors made in order to be able to switch from 2.75-3inch just in case i dont like the sound of the 3inch tubing.(it will probably be ok,it will also depend on how much they will ask for to do this job)