Does it not work off pressure and not a button as it'll be a mechanical flap and not electric??

The exhaust I took off a TTS and put on my V6 has the flap and is usually activated by going over a certain rpm? I think?

 

It should change tone when you press sport button on idle, it only stays open in 1st on my S tronic though, once in 2nd it goes back to normal until you get on boost as above, there is a big change on idle though as it opens both exhausts up. However this will be magnified on mine as I have the Titanium race system from Scorpion with only 1 backbox on the drivers side which is open all the time, my valved side has no backbox(silencer) hence sounds rather meaty and burbles when the button is pressed. You could test your valve out by doing the mod and having it open all the time see if there is a change, your valve could well be stuck at the minute and need freeing up though.

 

Yeah mine isn't working on idle. No difference in sound.

I assume it should work like this:

 

Can be heard here too:

 

On the RS the flap is vacuum actuated, via a solenoid valve. Application of vacuum to the flap actuator SHUTS the flap - as long as it isn't seized!

On my manual Mk2 RS there didn't seem to be much interference on whether the flap was open or shut after the Sport button was pressed.

The flap can be made permanently open by disconnecting and blanking the rubber hose to the actuator or simply kinking the hose and securing the kink with a ty-wrap.

 

Could someone take a few pictures of it so we know where it is, and which hose to block off?

https://audi.7zap.com/en/rdw/audi+tt+tt ... 253090/#33

viewtopic.php?f=19&t=1581042

Is this correct??
.

 

On the RS the flap is vacuum actuated, via a solenoid valve. Application of vacuum to the flap actuator SHUTS the flap - as long as it isn't seized!

On my manual Mk2 RS there didn't seem to be much interference on whether the flap was open or shut after the Sport button was pressed.

The flap can be made permanently open by disconnecting and blanking the rubber hose to the actuator or simply kinking the hose and securing the kink with a ty-wrap.

That doesn't explain the 2 videos I've posted though, they are like night and day. And when you cold start an RS with sports exhaust, it's like night and day for the first 1 minute. Really loud and then tones down, that's not just revs either as it only idle's at around 1.5k. After it's toned down, if I hold revs back at 1.5k, it's no where near as loud..

Could someone take a few pictures of it so we know where it is, and which hose to block off?

Stolen from VW Vortex:

The process is easy: get under your car (jack not required) behind the drivers side exhaust tip. Stick your head under there and you will see the flapper module for the exhaust. All you need to do is zip tie the vacuum line closed. There is even a metal clip there to hold the vacuum line, that I zip tied the line to. Whole process took all of 5 min, only need 1 zip tie, and is completely reverse-able at anytime. You can also disconnect the vacuum line and plug the holes, but the zip tie method is easiest, cuz everyone has zipties, but finding the perfect plastic plugs for those holes isn't easy.

It's the nearside, not "drivers" side, as that's relevant to US/EU markets only.

 

That doesn't explain the 2 videos I've posted though, they are like night and day. And when you cold start an RS with sports exhaust, it's like night and day for the first 1 minute. Really loud and then tones down, that's not just revs either as it only idle's at around 1.5k. After it's toned down, if I hold revs back at 1.5k, it's no where near as loud.

Your description of 'loud on cold start for 1 minute' is characteristic of the cat fast-warm-up strategy. On other VAG cars that was done using an air injection system but on the Mk3 RS it's done by altering fuelling and ignition timing during the first part of the cold start phase.

I don't recall that on my 2009 Mk2 RS, but maybe I missed it or it was added to later models?

Air injection: a small electric pump injects air into the exhaust ports. Excess fuel is injected and mixes with that air causing a secondary burn in the cat. The aim is to get the cat up to working temperature faster and hence reduce emissions.

It maybe that you are hearing only the effect of the cold start strategy because the exhaust flap isn't actually working.

I think you need to physically check that the flap moves when commanded by the Sport button.

 

That doesn't explain the 2 videos I've posted though, they are like night and day. And when you cold start an RS with sports exhaust, it's like night and day for the first 1 minute. Really loud and then tones down, that's not just revs either as it only idle's at around 1.5k. After it's toned down, if I hold revs back at 1.5k, it's no where near as loud.

Your description of 'loud on cold start for 1 minute' is characteristic of the cat fast-warm-up strategy. On other VAG cars that was done using an air injection system but on the Mk3 RS it's done by altering fuelling and ignition timing during the first part of the cold start phase.

I don't recall that on my 2009 Mk2 RS, but maybe I missed it or it was added to later models?

Air injection: a small electric pump injects air into the exhaust ports. Excess fuel is injected and mixes with that air causing a secondary burn in the cat. The aim is to get the cat up to working temperature faster and hence reduce emissions.

It maybe that you are hearing only the effect of the cold start strategy because the exhaust flap isn't actually working.

I think you need to physically check that the flap moves when commanded by the Sport button.

100% agree. Makes total sense. So, how do I check that? Because putting my ear next to the nearside exhaust and getting someone to do the sport button on idle does nothing.

Shall I do the zip tie trick and see if that works? As if it is done on pressure, then it should work. So if it works, then I know there is an issue with the sport button? Surely this must be common?

 

100% agree. Makes total sense. So, how do I check that? Because putting my ear next to the nearside exhaust and getting someone to do the sport button on idle does nothing.

Shall I do the zip tie trick and see if that works? As if it is done on pressure, then it should work. So if it works, then I know there is an issue with the sport button? Surely this must be common?

Apart from hearing the different exhaust note, with your ear next to the LH exhaust you should also be able to hear the 'clack' noise of the flap operating.
If your car is not lowered you should be able to get your head underneath that corner and see if the arm between the top of the flap spindle and the actuator moves.

If that arm does not move, pull the rubber tube off the actuator and feel if there is a vacuum being drawn:

Sport button in normal - flap should be shut, there should be a vacuum being drawn at the end of the rubber tube.
Sport button in Sport - flap should be open, no vacuum on the rubber tube.

There's no point in doing the zip tie trick unless the flap is open before you fit the tie - and I suspect that your flap may be seized shut.

 

From the workshop manual - Engine Mechanical, Engine ID CEP/B (D3E803BC234)
Repair Group: 26 - Exhaust System, Emission Controls
.

 

I have the cold start on my RS, and yes you hear the mechanical valve open and exhaust change when button is pressed on idle.

 

Right, finally getting to the bottom of this now.

Pulling the vacuum pipe off tells me the sport button is working, because when sport is on, the pipe does nothing, when the sport button is off, the pipe is sucking air, creating vacuum.

So, that must mean the valve is seized close...

Any advice? Please say this isn't a complete back box jobby? Surely must be pretty common?

 

Sport button in normal - flap should be shut, there should be a vacuum being drawn at the end of the rubber tube.
Sport button in Sport - flap should be open, no vacuum on the rubber tube.

Ha, the confusing thing is, I've just tested and had opposite results as above.

 

For the purpose of helping others, another post which concurs with, no vacuum with sport button and vacuum without sport button - viewtopic.php?t=227551&p=2094585#p2094083

 

What car do you have?

 

TTRS, I believe this was the only car to have the optional extra of sports exhaust?

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Sport button in normal - flap should be shut, there should be a vacuum being drawn at the end of the rubber tube.
Sport button in Sport - flap should be open, no vacuum on the rubber tube.

Ha, the confusing thing is, I've just tested and had opposite results as above.

I think you should read again.

You said you had this result

Pulling the vacuum pipe off tells me the sport button is working, because when sport is on, the pipe does nothing, when the sport button is off, the pipe is sucking air, creating vacuum.

which is exactly what I posted.
Sport in Sport (On) no vacuum on the rubber tube (the pipe does nothing)
Sport in Normal (Off) there should be a vacuum at the end of the rubber tube (the pipe is sucking air)

The other post you quoted, for the purpose of helping others, agrees with what I said.

As I expected, your flap valve is seized shut.

Advice? Yes, the flap valve and actuator are not available separately. For new parts you have to buy the whole back box and part exhaust system. Otherwise use some penetrating fluid (not WD40) and gentle persuasion.

 

Dude,

Sport button in Sport - flap should be open, no vacuum on the rubber tube.

This is wrong. When there is vacuum (suction), the flap is closed.

 

Have tried WD40, but I don't know what the "open" position looks like, can someone put up a photo of it open and closed. Not sure which angle to put persuasion.

 

Dude,

Sport button in Sport - flap should be open, no vacuum on the rubber tube.

This is wrong. When there is vacuum (suction), the flap is closed.

One last try:

You say "When there is vacuum (suction), the flap is closed" and that is correct.

It therefore follows that the opposite (which is what I wrote) is also correct:
viz, flap should be open, no vacuum on the rubber tube.

Think about how the 'flapper mod' works. You disconnect or zip tie the rubber hose to the flap actuator in order to keep the flap permanently OPEN.
No vacuum can get to the actuator and the flap stays OPEN.

Sport button in Sport - flap should be open, no vacuum on the rubber tube.

This is correct.

The original WD40 is not a penetrating fluid. Get some penetrating fluid, https://www.wd40specialist.com/products ... ating-oil/ get that into the top and bottom of the flap spindle and leave it overnight. Only then start trying to move it.

Look at the picture on page 1 for checking the flap operation with a vacuum pump. Your flap is stuck shut. Using the vacuum pump (which shuts the flap), the linkage moves upwards. Therefore you must persuade the linkage to move in the downwards direction.

 

Crawled under my 3.2 Quattro exhaust to take a peek this afternoon. Seems I don't have one on either side. :-(

 

Haha, yeah, you're absolutely right, my bad, must have read it wrong.

I'll try and find some penetrating fluid then, I did soak both sides of spindle earlier and gave it some persuasion but it wasn't moving.

 

Haha, yeah, you're absolutely right, my bad, must have read it wrong.

[smiley=mexicanwave.gif] [smiley=mexicanwave.gif] [smiley=mexicanwave.gif]

 

So this is becoming a bit of an obsession now. I've always thought the RS felt very tame and sounded very muted. I'm happy to say that the valve has been closed all this time despite pressing the sport button.

I've managed to free it up with some mole grips and penetrating fluid and my god it sounds awesome.

HOWEVER, my joy was short lived from blipping it on idle and having a huge grin, I then went for a drive and by the time I drove 1 mile it'd closed itself.

Problem number 2, valve doesn't stay open even if there is no vacuum, so I am assuming there is a spring in there (apologies if this has been said already in this thread) that isn't doing its job, no vacuum, springs holds valve open, right.

What's the verdict on this? Where is this spring that holds the valve open when there is no vacuum.

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