Single exhaust on 2.7t?

[jon c]

Hey guys,

I've been thinking a lot about an exhaust for my 6 and wondering if a single exhaust would be detrimental to the flow. I figure it would be lighter and cheaper to do since I'm not planning on making cutouts on my bumper. What do you guys think?

[African2.7T]

i say thats a no no buddy

[doobiesdaddy]

horrible idea

[TripleBlack]

I agree. I've seen a few C5 3.0's (non quattro) with the single exhaust and it looks horrible IMHO.

I say leave it as it is and just upgrade the entire system. More bang for your bucks since you've got the 2.7 and I'd doubt you'd have to make cut outs on your bumper if you decide to do so.

Keep us posted as to what you're gonna do and post pics.

[jon c]

As of now, I have a 2000 valence, which shows not exhaust at all. So, since I don't plan on exposing the tips at all, it wouldn't make a difference visually. I'm more concerned about the performance aspect. Again, does anyone know if there is a difference in terms of performance?

[TripleBlack]

As of now, I have a 2000 valence, which shows not exhaust at all. So, since I don't plan on exposing the tips at all, it wouldn't make a difference visually. I'm more concerned about the performance aspect. Again, does anyone know if there is a difference in terms of performance?

All good. If no one on here knows, I'll hit up my buddy Derracuda (he's on the Fourtitude forums). Or if you're on Fourtitude, you can send him a PM. He taught me a lot about my car and I'm sure he'd be more than happy to answer any questions you should have.

[FrankA6]

if i didn't have any cutouts i would do single , almost all high horsepower twin turbo cars do single.

oh and it should have better performance, this is what the B5 S4 exhaust system looks like, now, there really isn't much room to run 2 pipes off to the side like that on the A6 , so just make it just like that but just one side, and you're done, kinda like the APR kit i have the Miltek kit for the A6, just with one side.

[jon c]

I've been doing a bit of reading on the B5 forum and a lot of guys like to run 3.5" single or even 4"...I was thinking 3.5" cause I'm not planning on running GTs or anything crazy like that. A dual 2.5" setup will have a similar flow diameter as a single 3.5".

[TWINTURBOA6]

the benefit of owning a 2.7T A6 is having the monster twin turbo with a dual exhaust system!! if its facelifted it'll have the 2 pipes coming out of the bumper which looks super hot compared to a single side exhaust...

[wofman]

As of now, I have a 2000 valence, which shows not exhaust at all. So, since I don't plan on exposing the tips at all, it wouldn't make a difference visually. I'm more concerned about the performance aspect. Again, does anyone know if there is a difference in terms of performance?

If you go back on forum a few weeks there was a relavant thread to review (see Daft's post, in particular). The dual design allows smaller diameter to achieve free flow than would be required if you merge pipes (Milltek photo shown is still dual, Frank); savings on steel are diminimus. Lower pipes from extra diameter is invitation to clearance issue the way our underbellies are set up, I see no good reason to go there. If you don't go with extra diameter, you will suffer somewhat on flow (Do you have downpipe upgrade? if not, none of this really matters). I just did cut-outs of valence (pretty straightforward), but if you prefer keeping valence as is, it's just a matter of tips used.



wofman

[doobiesdaddy]

If you go to a single exhaust it will cut down exhaust flow and performance will suffer. It was a HUGE difference between the stock 2.25 downpipes and stock 2.25 pipes to mufflers to the new system I have of 2.5 turbo back. 2.7t has 2 turbos with 2 dedicated exhaust outputs. There is 2 exhaust pipes for a reason. Back pressure is the enemy with turbos.

[FrankA6]

(Milltek photo shown is still dual, Frank)

yeah i know, what i meant by that is it would cost less , only having to buy one muffler such....ya know.

that way he can still use dual, but! one 1 side and one muffler.

either way, i would just do what the factory layout is, and do turndowns.

[wofman]

And all of this brings us back to familiar point: while there are lots of alternatives for S4 2.7, A6 gets very limited aftermarket support.

Stealth, scmealth - stick it out the rear.

[African2.7T]

Warren i'm so jealous of your exhaust man, but i'm keeping mines stealthy looking. kind like that attention i get now bc people cant see my exhaust but yet the car growls.

[FrankA6]

yeah, i kinda like warrens short tips better than the long tips they give you with the APR kit.



plus my left side is a bit "off" and the fit isn't very good, i dunno if you can tell much here or not....but its is.

[jon c]

Frank, I don't see any issues with your fitment right now, though I can't see it in person.

As for the issue with the single exhaust, the only real concern I have now is clearance with a single 3.5" pipe.

Another question, do you guys get stainless steel pipes, and how are they bent by the shops?

[Concentric190]

if you don't want the pipe to show you can do a single pipe no problem. I would run a 2.5" pipe out of the turbos to a 3.5" all the way back. Very free flowing, will be louder aswell. If I was building a race car thats how I would do it.

However since I do want my tips to show I will be eventually doing 2.5" with an x pipe.