doveboat

My understanding is that the RS Sport exhaust is a different system up stream (mufflers, etc) that will exit at the "Sport exhaust style" wide oval finisher.

As an example, the V10 R8 has two pipes that exit at the oval finisher, not connected to the finisher.

Option is to pass on exhaust and do an aftermarket that ties into valve operations.

Ed

Nebuul

I doubt it is true since Audi has never mentioned any performance gain of any type being related to the sport exhaust. It only talks about sound and color. If they could even claim "up to 5 hp" then they could sell it as a performance piece. Also, I have not seen any tuner shops that have bothered to differentiate the different exhausts when dyno'ing the cars, and there don't seem to be two groups of TT RS cars (one with mysteriously higher HP than the other).

Huey52

Oh, ok, you are referring to your 2013 TTRS, not 2018. Yes, that is purely cosmetic and I don't appreciate when manufacturers do that either.

Of course one could say even directly attached tips are cosmetic as most invariably larger in diameter than their feeder pipes.

adg44

The RS Sport exhaust is purely for increased sound. There is no power output difference.

With that said, the sound from it is amazing. So there is no downside, and the black tips are an ide tidier that your car is equipped with the sport exhaust.

McTTRS

I am sure you are right but there is something that I do not understand. I have always believed that:
1. increased sound = reduced back pressure
2. reduced back pressure = increased (perhaps very small) power

So which of these two equations is not true and are your conclusions perhaps based on dyne (butt or otherwise) tests?

adg44

You don't have to reduce back pressure to increase sound. The only exhaust from Audi that increases power is the Audi Sport titanium exhaust for the RS 7 which was developed in conjunction with Akrapovic.

McTTRS

To increase sound you must vent more energy in the form of sound to the atmosphere. How you vent more energy to the atmosphere thru the exhaust system without reducing back pressure is clearly beyond my meager comprehension.

ormandj

You are partially correct. You are overlooking inefficiency in energy transfer, however. An exhaust can be designed to increase the coupling efficiency to the air, thereby increasing the output, without reducing back pressure. Additionally, you can mutate the output to make the sound more audible based on human hearing sensitivity. There are books written on this subject, but feel free to make a pitstop at wikipedia, as speaker horns are an excellent example of this.

https://en.m.wikipedia.org/wiki/Horn_loudspeaker

GrimTango42

Sounds like it would be cheaper, and easier for Audi to just have an exhaust with less back pressure, therefore higher sound and possibly a itty bitty tiny bit of power.

Audi never cares about shouting about their power increases. They don't even advertise true power output figures or 0-60 times. Audi's are notoriously more powerful and faster than advertised. Sometimes by a lot (In the case of the TTRS and the RS3 for example) you will very likely see a 1-4 HP boost from the sports exhaust due to the nature of what it is. Nearly all German car makers do not care to boast about little performance boosts with their options.

I would be highly surprised if they spent all this time and money to produce a complicated exhaust system to increase sound without decreasing back pressure. It would so much easier to just put a better exhaust system on and be done with it.

You might be surprised. Most people are when they realize that their "400HP" 5cyl actually makes 430HP and 420LB/ft. It is very common, and is already being found to be true from the 2017s and 2018s that have made it into the wild. The sports exhaust may very well add an extra 5HP to that...

McTTRS

I am inclined to agree with you and disagree with those who believe only what Audi specifically acclaims.