RichieC

Has anyone got a Bailey Evo Dump valve fitted to their Scoob?

Im in the market for a valve but I am unsure which one to go for. Ive heard good things about the Bailey but would appreciate some more info..price, fitting kit etc.

Also what sort of noise does it make? Is it particularly loud?? and does it make any differerence?

Thanks for any info, Richie

Lee

If its a vent to atmosphere one stop there and choose another.

What year car have you got ? Later cars have a bigger capacity and do not need changing.

Lee

The ECU provides fuelling and ignition depending on boost and incoming air (reported by MAF sensor).

A vent to atmosphere dump valve "opens" the closed system, bypassing the MAF sensor...

RichieC

Mine is a 1993 WRX.

Whats the problem with the vent to atmosphere type valves??

Cheers

Richie.

firefox

Lee,

Why does my car run ok then ?

lol

J.

ps - Just being awkward... but I agree... a few people have reported problems... if you are just after a BOV/DV for reliability reasons go for a recirc... but if its noise you want go for an atmospheric (either Apex-i, Blitz or HKS - but they aint cheap)

RichieC

Firefox, do you run a Bailey or what??

Richie.

Bajie

I have the HKS Sequential Blow-Off Valve.
Good it is ... Quiet it aint!
Differences, in MY opinion, the acceleration of the car has improved, I don't think its placebo, the car really feels as though the power is there all the time.
As for noise, I like it, sounds like a whiplash, turn off the stereo, lower the window and smile.
My friend picked me up in Gatwick recently. Heard the dump valve well before I saw the car!
BTW the more powerful your engine the louder the valve becomes (allegedly) so if are running standard boost and then up the power the valve becomes more ... vocal.
Hope I've helped.

firefox

Hi..

I'm currently running a HKS BOV...

Very good quality...but not cheap...

J.

Lee

Do you not find your valve open all the time when the inlet is at vacuum ?

Pete Croney mentioned they fitted one to Rob Mac's car for a trial and it was open most of the time - therefore the engine is sucking in air from the atmosphere, this being the easy route compared to through the intercooler/turbo/filter...

firefox

Hi there..

The basic (crappy) dump valves that just use a simple spring and diaphram are rubish.. if it was open then they had the wrong spring in it...or a leaky rubber/teflon diaphragm

If you search back through the archives, there have been many posts about dump valves, and I replied quite a bit

Most the problems associated with them have been poor installation (setting up) or the use of a crap valve... As far as I know, no one has had a problem with a HKS one ?

If they have, please prove me wrong.. and I wont have to type all this in again... lol

J.

ps - I believe Ian Gratton has a piston (Bailey version) atmospheric dump valve..and had problems.... but I think we established it was leaking...

David K

The way the evo or twin piston dump valve works is to have a secondary piston which is held shut on tickover (vacuum) by a weak spring thus not venting any air off whilst on vacuum.The dump valve then dumps air during a gear change because the pressure in the intercooler/pipes is high enough to force the weak spring back and open the valve.During positive pressure (on boost) the main piston in the valve is push against the secondary piston holding it shut.

David.