Won't go over 10-12PSI after ZZP stage 3

[brian]

I'm wondering if some experienced folks on here can help me out.

I just finished the ZZP Stage 3 installation including a dual-pass endplate and surge tank. I bought the stage 3 kit with the 2.8" pulley and 60# injectors.


The car gets to 10-12psi faster, but won't hit the 17-18 expected from the 2.8" pulley. I would have imagined the ZZP canned tune would have set the diverter/bleed valve to open after the expected boost level of 17-18--if this is what's even preventing the boost.

I sent an email to Tim over at ZZP and am waiting on his comments. I did a bit of research on the bypass mod, but I feel I shouldn't have to muck around with it because of the new PCM tune.

Any ideas?


-Brian

[Vander Nars]

going out on a limb here but could u be having belt slip causing you to not hit full boost? whats ur belt n tensioner setup?

[hnbracing]

you should try it to see if the pcm is comanding it open or if it is a mechanical problem

[brian]

It's the stock tensioner with the shorter GM belt.

How do I check and see if the PCM is commanding it open? I guess I could do the bypass mod to see if I get more boost. If so, the PCM is doing it and ZZP didn't apply the tune correctly. ?


-Brian

[brian]

I just did the boost bypass by disconnecting the intake side of the solenoid and plugging the hose. The car spins to 15-17psi now,... and rips--I can't believe this little 2.0L can pull so hard...

So this means the ZZP firmware didn't mess with the 12psi boost limit like their ZZP 1.0 info site says?


-Brian

[armcclure]

Zzp doesn't set their base tunes to open the bypass valve at all after
1st gear. It's a mechanical issue.

Look at the bolts that hold the actuator (black cylinder) on and you'll see one is slotted. Crack both bolts loose and rotate it to max pressure on the internal spring (pushing the rod into the actuator)

[brian]

Interesting... I didn't know the diverter valve was adjustable. Are there instructions explaining the specifics of the stock valve?

I'll run a few searches...

-Brian

[armcclure]

Not that I'm aware of. I just figured it out years ago when I put on a 2.8 and wasn't getting the expected boost.

[hnbracing]

Originally Posted by armcclure

It's a mechanical issue.

it may not be mechanical the boosbypass solenoid could be bad(it is powered closed and depowered open and that oring dose go bad) you dont want the max spring pressure on the bypass actuator because the boost pressure may not be enough to open the actuator if it gets commanded to open by the pcm for excessive iat2 that is why it has an adjustemnt screw to set the spring pressure and zzp does make tuning mistakes

[brian]

Hmm.. I suppose I could test the solenoid. How dangerous is it to leave to bypass mod in place during my daily commute?


-Brian