caz1562

I'm reading a lot of posts that talk about turbo stalling due to dump valve releasing the pressure causing compressor stall. This I believe is bad for the blades !!!!

Is there anyone who is technically up to speed with this scenario and in a position to explain exactly what this means and if it is safe to install ?

dhorwich

Hi,

I think you may have your wires crossed.... a dump valve prevents turbo stall, by allowing the propellor blade to keep spinning between gear changes.... if you have no dump valve the pressure pushes back on to the turbo blade and reduces the life of your turbo hence why subarus are fitted with dump valves fom new..

Dan

caz1562

Ah gotcha,

Now I understand, what about these VTA D/V's. Are these OK to use ?

dhorwich

Hi,

VTA dump valves do what they say on the tin... they vent the excess pressure to atmosphere instaed of back into the inlet to the engine like the standard one does, this is a recirculating DV..... the only real difference between the two is the sound and possibly a VTA DV can cope with a bit more boost pressure..!

Some people worry that a VTA DV will cause the car to run rich as the engine will see it as lost air, which is different on the recirculating DV which doesnt loose the air as its plumbed back into the inlet... however most good DV's dont cause a problem..

My car has a HKS SSQ dump valve which is one of the better ones..... alot of DV's specific for the scoob are made to work correctly and reduce the chance of running rich and causing poor idle e.t.c most have a twin piston design... well the forge and bailey ones do...

Dan...

[Edited by dhorwich - 8/18/2002 10:46:44 AM]