Turbo Help (FAO: Coops, Maxiboy, Dan.wii)

[Laine_16v]

Laine here, posting on Lee's account.

He's having a problem.

The car works fine, drives fine and boosts correctly on high and low boost. But it the dump valve does not appear to work correctly. Instead of dumping it appears to make a wastegate cahtter / stall sound instead, BUT its weak.

Obviously we started in the most obvious place (the dump valve), we took it apart and cleaned it, but there was nothing wrong with it. We then took the dump valve off and blocked the dump valve hole off (to induce proper waste gate chatter), but again it didnt really do much.

The dump valve will work occasionally but never fully you will sometimes hear a slight "tscch"

Any help?

[sideways danny]

it it's not getting chatter (compressor stall) with no dump valve fitted, it suggests it's not boosting. But you've said it boosts ok.

Could there be a leak somewhere, maybe one of the vacuum hoses?

[Coops]

as above really, vac hose issue maybe

see if you/he can get hold of a working valve off someone to test it

[Laine_16v]

Found a split in the dump valve diaphram, so we are going to replace that :)

[col]

COL HERE,...ive a TURBO (miffed) :cry: split hoses are turbos downfall amongst other things.. :wink:

[col]

BY the way thats exactly what happend with mine.......dump valves are goin out ,people prefer the chaaaaaatttter. 8) :lol:

[Gymnast]

If the DV has a split diaphragm it may not boost properly. Also, if the spring is too strong (for the boost level), or is seized, the DV will not work and you will get chatter.

IMO I would take the DV off and seal up the vac pipe ... they sound like a sneeze anyway :wink:

I have two 5 GTTs both without DVs, 160 + 180bhp, 15 + 18psi ... never any trouble. It's one less thing to go wrong.