View Full Version : Audi 2.7t Stage III application help

01-26-2009, 03:03 PM
I have an Audi with the 2.7 liter twin Turbo motor. I just had the turbos replaced with K04 units. This is part of a StageIII kit which has capabilities up into the 500+ HP range. My application is a bit milder than that, more like the lower 400+ HP spectrum. It is a dual exhaust with a balance cross over. This application is going to have boost levels in the 18-23psi range. I would like something that flows well, but is not reminisant of the loud Fart Cans that seem the norm in my area. This is a daily driver and the quieter the better, I do not want something that is going to drone me out of the vehicle as I am going down the road. Also please note that I have, and will in the future, put the vehicle on the track (one reason I like the tune ability of SuperTrapps). :)

I am considering the Stainless SC elite series 4" UNIVERSAL 17" or 24", 2.5" ID,BRUSHED SS. Mainly due to the existing OEM cut outs on my back bumper, I may be able to use 5" units, but I believe there will be some bumper hacking to get them in place.

Can someone tell me if this is a good fit for my car with the motor setup I have. Or if there is a better product for my application, can you please let me know what it is.

Thanks in advance

01-26-2009, 03:09 PM
Sounds like a fun car.
The larger the muffler the quieter it will be. 5" would be nice, but if you can't get them in there the 4 would be great as well. Again, longer the better.
If you have the room, the 24" with 12 discs each(supplied with the muffler).

01-27-2009, 09:15 AM
The application PDF states that the 4" series is good for up to 4.0L & 250 HP per muffler in a normaliy aspirated application, and that high exhaust flow applications (forced induction models and sustained high RPM) should assume (here is the confusing part) "slightly" lower Max HP and engine size numbers. :confused: I am well under the displacement value (even for a single muffler although I will be running 2 units If I go with the 4" units) but it looks like I am getting close to or at the limit on the HP output considering the above mentioned note on high flow applications.

Considering the following:
2.7 liter twin Turbo motor. ( K04 units)
Stage III (500+ HP capable, 400+ HP current tune)
boost levels in the 18-23psi range
dual exhaust with a balance cross over
engine really comes alive at approx. 2800 to 6800 RPM
Freeway cruising speeds are typically in the 2000 to 2400 RPM range (but boost numbers are low during cruising)

A) With two 4" units will I be cutting it too close to the limit because I am Turbo charged, and also I do plan to upgrade the intercoolers later this year and or next year, which will increase the power output somewhat.
B) Will the 4" models be able to flow enough without choking off the motor in the daily driver mode? In the documentation it states that "open" exhaust characteristics are obtained at 20 to 24 disk plates which would be fine for when I take it to the track. In order for the 4" to flow properly do you really think 12 disks will be enough for flow and maintain a good quiet tone for daily driving? Previous experience with these mufflers noted that the more disks the louder the exhaust note.
C) I understand that the 24" model will be the quietest over the other shorter length units. You are saying that the 5" DIA. Trapp will also be quieter than the 4" DIA. Trapp?

01-27-2009, 11:54 AM
As stated originally, the 5" would be the best, both flow and sound wise.
Personally ran a pair on a 383 SBC that was well over 500, 12 disc on each was perfect. Did not impeed flow at all and kept sound as low as possible.
If you can, that would be the best.
The 4" with 12+ discs would be fine for the street. As stated in the tech info you could go up to 24 discs (at which point you are starting to outflow the core itself).
From what you mention below, make room for the 5", it will adjust and accomodate more down the road.