this is me holding my hands up and say yes the dump to atmos DV i had was not really suited to the VRS....however the noise i still really miss but the performace diffrence with the new hyperboost one is extrodinary! no lag, loads of torque, more performance in very gear... jeez i thought it was quick before and was running well how wrong i was...now its as quick as it should be and running like it should...feels like 50bhp has been added.. its a diffrent car...i feel i've wasted a year :( and should have just left the orginal DV on or gone for rec DV from the start....but i really really wanted the loudest one avalible...oh hum

Joel

can the wrong DV really make that much difference then?

Yes - vent to atmosphere DVs just aren't gonna work properly with the 1.8T. If you want the noise, get an ABD or Carbonio cold air intake (CAI) trust me

I would of thought an Atmospheric DV actually wastes potential energy as it stops the turbo spooling where as the recirculating one keeps the turbo spinning.

Yes - vent to atmosphere DVs just aren't gonna work properly with the 1.8T. If you want the noise, get an ABD or Carbonio cold air intake (CAI) trust me

Or a PA system with a "whoooooshhhh" sample

I would of thought an Atmospheric DV actually wastes potential energy as it stops the turbo spooling where as the recirculating one keeps the turbo spinning.

No - atmos DV vents pressure to air thus stopping the air from going backwards and stalling the turbo...

If you want the noise, get an ABD or Carbonio cold air intake (CAI) trust me

Joel if you want loud get the ABD CAI

No - atmos DV vents pressure to air thus stopping the air from going backwards and stalling the turbo...

Doesn't actually stall the turbo it stalls the air, this shock loads the turbo's blades and also the bearings. The turbo will quickly start to spool down but the air intake will stay pressurised.

With a DV your turbo is protected but the intake is depressurised and has to be repressurised on application of the throttle.

From a pure performance point of view with quick gear changes the best way is to have no DV. Trouble is unless you have a deep pockets and a mega turbo with 360degree bearings your turbo isn't going to last long.

DV's are fitted to protect the turbo and wastegate not for any performance increase.

Not been to much involved with VAG petrol turbo's but had plenty of experience with Cosworths and Scooby's, problems usually arise when you fit an amto DV onto a car with a recirc DV because the ECU gets confused as it sees airflow via the MAF when the DV operates. Also if the diaphram springing and dump pressure of an atmo DV is set too low it will probably sound good but all the pressure will be lost from the intake and plenum, when you come back on throttle the turbo will have to repressurise the entire intake.

Cheers

Lee

If you miss the "ptshhh", while I was at the Donny car show a couple of weeks ago, a stand was selling a "Dump Valve Simulator" which did sound like a proper DV. Was

Joel, I thought your old dv was causing problems. Especially when you only got 3bhp more than my car!

Joel, I thought your old dv was causing problems. Especially when you only got 3bhp more than my car!

true true

Joel

Thanks for the 'no holds barred' feedback, Joel, and interesting to know just how detrimental the atmospheric DV was to your car's performance.