4AGZE Air Bypass Valve...

[jondee86]

I got one of these thinking that it might come in handy one day...



The pic shows the top of the servo. As I had never seen one without the sticker
on top, I was interested to see that there is a socket head screw threaded down in
the hole on top of the servo. Presumeably this is an adjustment screw used by
the factory to trim the preset boost limit for the GZE ?

Has anyone ever experimented with this screw to see what (if any) affect it has
on the boost limit ? I am aware that HKS at one time offered a reworked ABV that
was fitted with a new top to the servo and incorporated an adjustment screw. But
there does not seem to be any info on the web as to what the factory screw does.

Nor have I been able to find any technical data, cutaway drawing or diagram that
explains exactly how this valve works.. and I'd like to know what's inside

Cheers... jondee86

[evil_si]

Ive never played or experimented with one, Always bypassed them in order to run higher boost

[jondee86]

Yuss... I know that it is common to eliminate the solenoid and just use
the ABV as a standard bypass valve, without the BOV function. And since
the ABV is a non-adjustable factory valve, it is a fair guess to say that the
little screw on top is just for trimming the BOV release pressure.

What I'm trying to figure is how the valve works, as the vacuum is under
the diaphragm instead of on top like every other bypass valve.

Anyone got a dead one lying around I could cut open ??

Cheers... jondee86