I've spent a year trying to figure htis out.

I'm not going to say what I've tried - I'm just going to tell you all the symptoms and let you guys throw ideas out there.

V1 SC - 3.12" Pulley
Vacuum is at 15Hg

Boost in all gears:

1st Gear - 8-9PSI
2nd Gear - 6-7PSI
3rd Gear - 5-6PSI

It seems the longer I am in boost, the less boost I get.

 

BOV needs a tighter spring or to be cranked down. I had the same problem but could not get more than 6 psi at WOT (with a V2 & 3.125 pulley). I changed out the spring to a stiffer one and tightened the set screw a little and WAAA LAAA I had 12.5 psi.

 

Yeah - I knew that would be said first.

I've installed 2 BOV's, the latest being a HKS SSQ that is supposedly impossible to boost leak because it mechanically can't activate at all unless there is vacuum.

 

OK - I may as well list what I have done.

2 different BOV's

Checked SC Piping/clamps constantly - no holes or leaks - RTV'ed Ambient Sensor into place

Removed and re-installed MEVI with new gaskets - used RTV on top of that.

Used a stethascope on every vacuum hose I could find using the FSM - no cracks or holes found.

Compression checked - 210/cylinder

Replaced PCV Valve

Replaced all plugs - regapped.

Tried 2 different belts - tried tightening it, loosening it, then tighteneing it again to 70 degrees deflection.

3 different boost gauges.....installed on several spots off the manifold.

Replaced EGR, TB, and Manifold Gaskets.

I generally post this question every 3 months, hoping someone knows something I haven't checked yet.

 

I just won this on EBay - hopefully it helps.

http://cgi.ebay.com/ebaymotors/ws/eB...ayphotohosting

IanS

 

Did another compression check (just to be sure) again today - 173-176 in all cylinders - (all but 2 were at 175).

Pretty consistant and well within spec.

Waitingo n the vacuum leak detector to show and see if that helps.

 

Belt slipage?

 

Gone through 2 belts now - doing about 60-70 percent deflection just like you once suggested, Mardi.

According to my Dynos from last week, there is no evidence of any slippage.

IanS