2019 A1 35 TFSI EXHAUST TAILPIPE VALVE/FLAP

[MALC-AS24]

Despite having the car from new, I have only just noticed that the inner pipe of the twin tail pipes on the rear silencer box, has a valve / flap fitted.  What is the purpose of this - does it open when certain revs are reached - and is it always operative or just in dynamic mode.

Also I find that the exhaust is too quiet- difficult to hear what the engine revs are doing -  and would prefer a slightly more "sporty" note, although nothing too dramatic. The afore mentioned valve doesn't seem to have any effect on noise output. Apart from fitting an after market sports system, has anyone tried "modifying" the standard back box silencer by removing some of the "stuffing".

[Stevey Y]

2 hours ago, MALC-AS24 said:

Despite having the car from new, I have only just noticed that the inner pipe of the twin tail pipes on the rear silencer box, has a valve / flap fitted.  What is the purpose of this - does it open when certain revs are reached - and is it always operative or just in dynamic mode.

Also I find that the exhaust is too quiet- difficult to hear what the engine revs are doing -  and would prefer a slightly more "sporty" note, although nothing too dramatic. The afore mentioned valve doesn't seem to have any effect on noise output. Apart from fitting an after market sports system, has anyone tried "modifying" the standard back box silencer by removing some of the "stuffing".

Hi the flap opens up at higher rpm to help with the expulsion of exhaust gas, as for filleting a standard exhaust back box if you get it wrong they are very expensive to replace and even if you manage to get the baffle insulation out is all you will be left with is a nasty resonating tin box which is clearly audible in the car, you can always go waste money on an aftermarket system, they will happily produce loads of customer depositions as to how much faster the car goes with its new Carlos Fandango super size straight through pipe, sorry to be the bearer of bad news but it is just an illusion caused by the extra noise.

You don't think Audi spent thousands of hours on Dynos developing the optimum exhaust flow rate for your engine including back pressure breaks just to have some wag with a unit full of stainless steel tubing and a pipe bender doubling up on performance for only £299.00, its the oldest formula in engineering, exhaust gas pulses are circular if you have a race car thats running at max revs all the time by all means have the biggest straightest pipe it will clear the gass pulses really quickly, unfortunately if you are running your mum down the shops in traffic you don't need a massive bore pipe as this will rob you of the initial torque you need to just pull away and like all those who have the big bore exhaust you will have to rev the nuts off the car to pull away.

Steve.

[MALC-AS24]

Cheers Steve - Sound advice ( excuse the pun ) 

Malc