Just installed "A" pod and 20psi boost gauge today(gonna be a fun toy I can tell:cool:) when i stomp on it from a stop, the boost peaks at 15-16psi:eek:, then sustains 8-9psi up to 80 km/h. After reading several threads on the subject, I understand that I should only see an 11 psi spike, then a semi-constant 5-7 psi.
This got me wondering how accurate the gauge is?
I hooked up to my buddy's Snap-On Modis scanner, at went for another tear.
According to the scanner, the peak was 150 Kpa, then leveled at 138-142Kpa.
I did the conversion and found 140 Kpa=approx 21psi?!?!

How can this be? Am I reading this wrong? Does the MAP and/or Boost sensor see things a lot differently than the gauge?Did I inhale to much brakleen when I shined up the upper plenum?

Somebody please answer this before I start drinking heavily in escape of this dilemma.

thankyou

Take into account standard air pressure?

no chris I didn't, just read what was on the screen.

what would be the calculation?

IIRC it should be boost shown on the computer minus barometric pressure (someone else will have to correct me here).

As a good avg, assume baro pressure to be 100kpa. 150kpa IIRC should be factory setting at peak boost. Sounds like a spike to approx 7-8psi relative boost.

thanx chris, i think I got it, I then show 7-8 peak and 4-5 steady.

Apparently the modis unit does not take SAP into account.

Also my gauge is out appr. 1-2 psi.

I still wonder why the gauge spikes to 16psi?

Mine would spike to 18psi spiking to 16 is not an issue, ecm will lower it

My truck at cruise speed is about 5 - 7, when my heavy foot takes over, goes up to 15 - 17. (that is all when my acuator works) Have to run some tests to see if I have a vacuum leak...

Mine would spike to 18psi spiking to 16 is not an issue, ecm will lower it

so it seems this is normal then. I now will commence heavy drinking in celebration. Thanks to all for the input:D