R.B.

I have noticed recently that my boost is not quite where is used to be running my APE II chips. Normally I see around 1.8 bar and now I am seeing around 1.6 bar on my stock guage. I read somewhere that if you take off the blow off valve and blow into either of the large inlets that air should not come out. Is this true?

Blowing into the bottom inlet pipe, I could not hear any air coming out. Blowing into the side inlet pipe, some air came out the top small hole.

Is this a valid test?

Thanks,
R.B.

MarkRobinson

Just put a 12" piece of vacuum line on the nipple & suck on it: if zero resistance (keep sucking, never builds up vacuum, nice oily taste , then the valve is shot. If you can actuate the valve with vacuum & vacuum increases, then its' good.

Mark.

KuHL 951

Ditto-Just checked mine last weekend, all I got was fuel taste and absolutely no vacumm at all. Ordered the EVO Diverter Valve from Paragon. The OEM, even the 'upgraded' 993 TT they sell now only lasted me a year. This is one part that benefits from aftermarket design.

R.B.

Thanks guys. i'll check it tonight.

-R.B.

Missin2

yuck.. I would save my self the pain and jsut get an aftermarket recirculating valve.. those stock ones are junk..

the Turbo XS one they make for VW's is a prefect fit (in case anyone is interested)..

TRWright

I have the EVO valve, too. It sounds sexy (loud) as hell with a maf. Looks way better than the stock one, too.

Maciek

Mark,
Do you do this test with the valve mounted or do you remove it first? Thanks,

Dark Lightning

Installed or removed, makes no difference.

R.B.

Well I tested it and it does not hold vacuum. I ordered the EVO from Paragon.
We'll see if it makes a difference.

-R.B.

testarossa_td

Evo is the one I hear the most about.
I have this one with a MAF and it makes that sweet BOV sound.
(it is pretty big, and needs some modification of the lines to get it to fit under the hood, their other models might fit no problem)
of course I got that sweet sound with the 993 OEM BOV as well.

MarkRobinson

That should work. Yes, it makes no difference whether it's installed or not for simple mouth-vacuum testing.

Mark

R.B.

Just to update, I received my new blow off valve (EVO) and before installing it I wanted to test it. Blowing into the 2 large inlets and both were sealed. However sucking on the small inlet, I still did not get any vacuum built up. I installed the new BOV and took it for a test run. Still no difference in the boost (1.6 - 1.7 bar on stock guage 3rd gear WOT)

R.B.

KuHL 951

If you can't get a vacuum on the top port, your new part is faulty. My new one stuck to my tongue when I slipped a hose on it.

pk951

RB

If you are using CV and stock WG boost is set at 12 psi or so, drops off at higher boost to 9 psi or so.

In most cases stock WG spring gets weak with time.

A good Tial WG will fix that with MBC.

ibkevin

Mark is dead on-

The BOV is one of the first things I checked when I bought mine, and sure enough it was shot. The turbo is "on or off", very brief transition period. Winter driving back from Wisconnsin was a real trick!