View Full Version : Dumpvalve question shocker on 22B.com

25th November 2002, 15:46
Hi guys,

I have a question: I'm still using the OEM dumpvalve, and that worked pretty well with the VF23 (MY99 car) so far.


Since fitting the Pace FMIC, I do notice some strange "jolts" after lifting off & getting back on the power immediately. Like the pressure is still there.

Almost as if the DV doesn't dump enough air. Now it's great for responsiveness, but I'm a bit concerned the VF23 (well, its bearing) may not like that much.

Could it be that this is caused by the volume of compressed air in the longer pipework ?

Am I correct in worrying, and do I need to look at another (recirculating) DV ? I really don't fancy the noises these "aftermarket" things make, just want to keep the VF23 alive.

Any thoughts on this would be appreciated.


PS: any chance of getting my old password back ? I clicked on the "Forget link" but it won't send me anything because I have more than one user ID on the email address http://bbs.22b.com/ubb/frown.gif

25th November 2002, 16:05
Merry xmas Theo.
(Strangely the contents of your post cannot be seen by me as I can't connect 'dumpvalve related questions' with the evilbevel I know http://bbs.22b.com/ubb/wink.gif )

25th November 2002, 16:06
my forge re-circ is for sale, works really well with the pace fmic.

Bob Rawle
25th November 2002, 17:44
That's because the bov doesn't have the capacity to vent all the extra pressure in the system, the jolt is reverse pressure wave kicking the maf, be aware that this sort of reverse wave will ultimately cause the maf to fail, I "lost" four before I sussed it out and installed a suitably tweaked Forge recirc to cope. Its car specific, the factory bov never caused me any issues, just affected turbo spool.

BTW Christian the HKS won't vent air fast enough either.


[This message has been edited by Bob Rawle (edited 25 November 2002).]

26th November 2002, 16:24
Chuck, OK, I'll admit it, I'm an imposter http://bbs.22b.com/ubb/smile.gif Merry Xmas anyway to you too !

Bob, thanks for that. Not just my imagination then. Nackered MAF's is something I'm trying to stay away from, very unsuccessfully I might add http://bbs.22b.com/ubb/frown.gif http://bbs.22b.com/ubb/smile.gif

Any pointers as for where to get the suitably tweaked Forge ?

Adam M
26th November 2002, 17:00

Bob Rawle
26th November 2002, 19:22
If you remind me of your full car spec, turbo etc etc I can set one up for you, I have all the springs and shims here in addition to the dump valves. Mail me as per profile if you want.