StephV6 Posted November 25, 2004 Report Share Posted November 25, 2004 hi, I've read quite a bit about the exhaust valve mod some of you have done their R32 btu still have some questions. Sorry if some of those questions have been answered but you'll have to excuse my French (quite litterally): 1- How is the valve operated? Venturi effect dependant purely on air velocity thru the exhaust or by some relay controlled by the car ECU? if the latter, will disonnecting the pipe log a fault? 2- Why do you have to seal off both pipe and actuator? just for dirt problems? 3- I checked my self (at the expense of some years of my life thru lungs cancer tho I tried not to inhale !), the valve is fully open at idle and I understand it is also fully open at full throttle so when is closed? 4- Dont know about R32's but on mine it only operates one of the 2 pipes. so does it really have any effect? Thanks PS: I dont have a R32 but an A3 3.2 Link to comment Share on other sites More sharing options...
Riz Posted November 25, 2004 Report Share Posted November 25, 2004 1. The valve is control by a airpump in the engine bay and is indeed air controlled, the ECU controls the flow of the air and im not sure if it brings up any error codes although i did wonder if it was possible just to stop the pump by a setting via VAG-Com. 2. Sealing off the pipe and the unit is indeed to stop rubbish etc getting inside, but some people just clamp the pipe rather than removing it. 3. The valve is closed until approx 3000 rpms approx, this is when it opens and lets the full flow happen, also the valve opens above a certain speed, not sure but could be something between 40-60mph. 4. The valve does indeed just work on one of the pipes... the basic idea is the same. Riz Link to comment Share on other sites More sharing options...
StephV6 Posted November 25, 2004 Author Report Share Posted November 25, 2004 Thanks Riz I'll check again this weekend as the valve seemed fully open at idle tho. Steph Link to comment Share on other sites More sharing options...
Riz Posted November 25, 2004 Report Share Posted November 25, 2004 [ QUOTE ] Thanks Riz I'll check again this weekend as the valve seemed fully open at idle tho. Steph [/ QUOTE ] Mmmm maybe its slightly revised but also the exhaust system on the A3 would be tuned for a smooth barble whereas the R32 is pure vrooooooom! Riz Link to comment Share on other sites More sharing options...
R32North Posted November 25, 2004 Report Share Posted November 25, 2004 Just ditch the boggo exhaust and fit a shiny aftermarket jobbie. Non of the AM's have the valve so it can be cuasing any problems or logging faults :-) Link to comment Share on other sites More sharing options...
Riz Posted November 25, 2004 Report Share Posted November 25, 2004 [ QUOTE ] Just ditch the boggo exhaust and fit a shiny aftermarket jobbie. Non of the AM's have the valve so it can be cuasing any problems or logging faults :-) [/ QUOTE ] Naaa stick with stock... Audi`s arent supposed to be loud Riz Link to comment Share on other sites More sharing options...
StephV6 Posted November 26, 2004 Author Report Share Posted November 26, 2004 that's good good news there wont be any fault am with you Riz, wont spend 600quid just for noise and see some 10sqmm of nice chrome seen loads of R32s recently (even saw 4 in 1 day once!!!) but none willing to play... shame as I think there cant be anything between the cars so could be really interesting anyone near Watford? Link to comment Share on other sites More sharing options...
JasT Posted November 26, 2004 Report Share Posted November 26, 2004 Sorry for the possibly stupid question, but does the valve suck air out from the exhaust, thereby making it quieter? Link to comment Share on other sites More sharing options...
StephV6 Posted November 26, 2004 Author Report Share Posted November 26, 2004 the valve only blocks off one pipe. how does this affects the noise I am not sure Link to comment Share on other sites More sharing options...
graeme86 Posted November 27, 2004 Report Share Posted November 27, 2004 To clarify: The valve is actuated by a vacuum pump situated under the left rear of the vehicle, which is controlled by an electrical signal from the ECU. 1st requirement: Road speed must exceed 45 MPH 2nd requirement: Engine RPM must exceed 3400 The flap closes the system back up when RPM drops under 3000 RPM, or when road speed drops back below 45 MPH. Link to comment Share on other sites More sharing options...
ianm Posted November 29, 2004 Report Share Posted November 29, 2004 [ QUOTE ] The valve is closed until approx 3000 rpms approx, this is when it opens and lets the full flow happen, also the valve opens above a certain speed, not sure but could be something between 40-60mph. [/ QUOTE ] [ QUOTE ] The flap closes the system back up when RPM drops under 3000 RPM, or when road speed drops back below 45 MPH. [/ QUOTE ] Hope this isn't a stupid question, however... Saying as the valve is normally closed until certain conditions are met (i.e. speed, rpm) if we clamp/block the air flow to the valve actuator doesn't this mean that the system will be <font color="red">closed</font> all the time? Wouldn't we want it to be <font color="red">open</font> all the time?? Link to comment Share on other sites More sharing options...
StephV6 Posted November 29, 2004 Author Report Share Posted November 29, 2004 I think valve is kept open by a sping and the air pump closes the valve thus the valve is always open when not operated by the pump Link to comment Share on other sites More sharing options...
ianm Posted November 29, 2004 Report Share Posted November 29, 2004 So as soon as you start the engine it closes the valve... then opens it again at 3000rpm / 45mph?? Link to comment Share on other sites More sharing options...
StephV6 Posted November 29, 2004 Author Report Share Posted November 29, 2004 graeme86, r u sure about the valve being closed at low rpm and not the opposite because I have checked on mine and the valve is definitely open at idle, ie about 800rpm. Link to comment Share on other sites More sharing options...
rich63 Posted November 30, 2004 Report Share Posted November 30, 2004 The valve is definately open when engine is not running, after starting 2-3 seconds later when the vacuum has built up you should hear the valve close. If you don,t hear any change in exhaust note then the valve may be seized in the closed position (unlikely but possible), you could of course get your wife/girlfreind to get down under the rear of the car and check to see if the valve operates (obviously ensuring first that her insurance policy is upto date and that you don't have it in reverse) Link to comment Share on other sites More sharing options...
Daemon Posted November 30, 2004 Report Share Posted November 30, 2004 Just to clarify something. The vacuum pump cycles on only for a short time to evacuate air from a round green vacuum resevoir (both located above the muffler heat shield on the left side of the car) and then shuts off and stays off most of the time. Each time the vacuum solenoid controlled by the ECU opens and closes it decreases the vacuum in the resevoir a little bit. When it drops below some threshhold the pump fires up again.. and so on and so forth. The flapper valve is *definitely* open when the car is not running (spring pulls it open), and the ECU forces it closed at idle.. Stays closed from idle to >45mph and >3500 rpms, then opens again. When slowing down, it closes a little lower speed and lower rpms. ian Link to comment Share on other sites More sharing options...
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