Audi TTRS Exhaust Flapper/Zip Tie Mod – How to
One of my favourite things about my Audi TTRS is the note of that amazing 5-Cylinder engine. The car sounds fantastic and even better when the Sport button is activated. Once sport mode is engaged, a flap in the exhaust is opened up which releases more of that great exhaust sound.
One thing that annoyed me slightly was that I wanted this sport mode to be engaged all the time, but you need to press the sport button each time you get into the car instead of constantly staying on, and flap remaining open.
After searching through google to find an answer to this, it turns out that I wasn’t the only person looking for this solution! One complaint from other TTRS owners whose cars were fitted with the optional mag ride was that sport mode also triggers the suspension to become stiffer, which some found a bit of a harsh ride.
It also turns out even in sport mode the exhaust valve is not open until a certain RPM in some gears (around 3,000 RPM, I believe), which made me even more eager to find a way to keep the flap permanently open.
After some searching, the fix is easier than I could have ever imagined and only cost me the price of a zip tie!
This fix can also be used on the Audi RS3 and some other Audi RS models which have a vacuum activated exhaust flap
Let’s take a look.
What is the exhaust flap for?
It’s a vacuum-actuated valve that opens and closes depending on the speed and rpm of your engine. The main purpose of the valve is to be able to switch between a quieter and a louder/sportier sound from the exhaust.
As I mentioned above, even when you have sports mode engaged, the flap will sometimes close at certain RPM’s – I believe this is something to do with emission regulations.
How to Do the Flapper Mod?
There are two ways you can do about the flapper mod – either way, will take you about 5 minutes in total and is completely reversible if you want to change back ( not sure why you would! )
- Use a zip tie to kink the vacuum line ( the method I used )
- Remove the hose altogether and plug the end of the hose
Step 1 – Locate the vacuum hose
The first step is to get under the rear of the car on the passenger side ( on a right-hand drive car ), Or the Drivers side ( on a left-hand drive car ). There is no need for a lift, you should be able to squeeze under while lying down.
If you look underneath the exhaust pipe on that side you should see a little black hose that looks like this.
Step 2 – Start the Car and Make Sure the Flap is open
This part is very important, as if you zip tie the hose before doing this, you could potentially zip tie the valve closed which is the opposite of what you want to happen.
All you need to do is start the car and wait for the cold start to finish. ( The flap will stay closed until this is finished no matter if you have the sports button pressed or not )
Once the cold start is finished, press the sports button and you should hear a click sound of the exhaust flap opening.
Step 3 – Zip tie the hose
Take your zip tie and go back to the hose underneath the car and zip tie a kink in the line like this. Once this is done, the flap is no longer controlled by a vacuum and will not open or close anymore and should stay in an open state.
Flapper Mod – Worth It?
I wish I had done this to the car sooner, the difference is noticeable, especially at lower RPM. ( Higher RPM where the flap was open anyway sounds the same ).
The exhaust note is deeper and angrier when at slow speed, and there is an improvement ( The way it should sound in my opinion! )
Sometimes When going at slow speeds in the first and second gear you can hear some pops and burbles in the exhaust which sounds awesome, which were never audible before.
Doing this mod is worth it, especially since it’s so quick and easy, and practically free.
Next up, I am going to get some Secondary Cat Bypass pipes to free up even more sound!
About the Author – Darren O Hara
Darren is the founder of the DriveDetailed blog and is a keen detailing enthusiast living in the rainy south of Ireland. When he is not cleaning his car he is always researching ways he can improve his techniques and enjoys testing out new products.
Darren currently drives an Audi TTRS and is a big fan of performance cars.
You can follow Darren on Instagram @darrenoharacork
One thought on “Audi TTRS Exhaust Flapper/Zip Tie Mod – How to”
I was livid the day I got my new RS3 delivered in 2019 to find out they tuned the flaps closed. I looked at ever possible option to reverse it and there is no simple solution unfortunately. Everything has a downside. If this is your DD on a brand new car who’s warranty you value, Audi will know the next time you bring it in for service. The vacuum pressure will be out of spec when it’s connected to their systems. The dealer may not care, but if you have an expensive repair and are under warranty, they have no control over the decision. You data goes offsite to the decision maker. There is a long list of parts that this immediately voids any warranty on that i have.