Just wondering what the normal operating range is for the VAC and pressure on the turbo. Under normal driving it usually registers 60-80 kPa(8-11 psi) VAC and under acceleration it registers 40-80 kpa

 

It really depends on elevation and air quality...But stock you can see anywhere from 8 to 17 psi depending on conditions. and at idle you should be at about 20 inches of vacuum...

 

Thanks

 

With the GMTU added, acceleration should be between 23 and 25 psi of boost. No dis "bad", just an add on M8!

 

Not exactly correct. Those numbers are a little high but "may" be obtained under the right conditions: vehicle, altitude, air quality, etc.

Mine at around sea level will hit about 19-20 w/GMTU on normal days. On some crappy air days, it may peak at 21.
(and yes mine is running correctly. No boost leaks and hitting full power by the RPD readings)

Like the tech from GM's performance division told me. In a nutshell, "It will put out the amount of boost needed to obtain the power levels required by the ECM and the torque management programming."

 

[QUOTE
Like the tech from GM's performance division told me. In a nutshell, "It will put out the amount of boost needed to obtain the power levels required by the ECM and the torque management programming."[/QUOTE]

This is exactly correct. High PSI boost levels do not mean your SS is making more power than another SS if they have the same tune. Just means your turbo is working harder to get there.

 

Just saying, I got the GMTU in 2008 and still get 23. Can't say much more.

 

I don't doubt your boost numbers at all.

My point was, telling the OP to look for 23-25 with the GMTU is a little misleading.

Mine stock would only hit 14 when it was brand new.

 

I had 13 -14 stock also. Everone's did! The GMTU should give you at least 23 lbs of boost with the GMPP download. If not you have leaks in you piping, etc. PERIOD son.

 

Sorry, but you're wrong. I don't have any leaks in mine and it's putting out the boost it needs to achieve the GMTU power levels.
Did you happen to read my 1st post above? And fiveothis agreeing with it?