All alone.........

tut · Post by **tut** » Tue Oct 16, 2007 11:31 pm

Just ordered one but its a re-circulating diverter valve, dumps back into the system and not to atmosphere, so maybe a soft sigh.

tut

Post by **campbell** » Wed Oct 17, 2007 11:22 pm

tut wrote:Just ordered one but its a re-circulating diverter valve, dumps back into the system and not to atmosphere, so maybe a soft sigh.

tut

You probably haven't heard one of those since Helen Shapiro.

Rich H · Post by **Rich H** » Thu Oct 18, 2007 9:14 am

Recirc dump valve just dumps all that hot, compressed air back into the system, get rid of it! Sounds chav as hell but it does actually work better... It will slightly unload the turbo but it bumps up the temperature instead.

As I understand it anyway.

tut · Post by **tut** » Thu Oct 18, 2007 9:35 am

Rich

Until I read up on the subject I thought that the only choice was a dump valve to the atmosphere, but then I saw on the Forums that with the Audi engine that is not a good idea, the ECU sees it as a fault, ie a leak in the system, and takes the wrong action.

The standard Bosche diverter valve does the same job as the replacement, ie puts hot charged air back into the system, but as it is a rubber diaghram type, and prone to failure at higher mileages, it does not do the job as well as the stronger twin piston type, especially with a re-mapped engine.

It seems from those that have fitted them that it does work, with a smoother gearchange and less turbo lag, and as it is a straight plug in swap job, it will be easy to do a back to back.

tut

BigD · Post by **BigD** » Thu Oct 18, 2007 11:00 am

VTA dump valves also cause the car to run rich momentarily as the MAF has measured the air but it has been dumped so it is puting the fuel in to match the measured air which is no longer there.

Also you can get turbo stalling and rough part throttle and cruising problems for the same reason.

More Turbo chat please!

tut · Post by **tut** » Thu Oct 18, 2007 12:58 pm

Thanks Don, exactly what I was told, but put better.

MAF, Mass Air Flow sensor?

tut

BigD · Post by **BigD** » Thu Oct 18, 2007 1:20 pm

tut wrote:Thanks Don, exactly what I was told, but put better.

MAF, Mass Air Flow sensor?

tut

Yes, sorry.

Despite all this I have a VTA dump valve on mine so I know the problems first hand.

I am looking at getting a dual BOV which recircs on low boost (i.e. just cruising, town driving or part throttle) and vents to atmosphere on higher boost pressure. Should be best of both worlds hopefully.

Rich H · Post by **Rich H** » Thu Oct 18, 2007 2:37 pm

Hairy muff!

I found a turbo for the Porsche but I need to find somewhere to fit it.

Did someone say turbo lag?....! :shock

(No that isn't me!)