Thread: went back to the dyno and cant make over 15 psi?

l32 bottom
stage 1 zzp heads
z7 turbo
st3 cam
7/8 triple edge trans
60 lbp injectors
700 hp fuel pump
06 car that was na
05 gtp pcm car did 330 whp at 14psi to 6500 rpm as soon as it gets turned up a to 15 or over dies about 5100 - 5200 rpm looked like 2 bar map was maxed out so tried 3 bar car ran terrible
its like its hittin a governor ....is there something in the 05 gtp pcm that hp tuners cant see?looking to hit 400 whp what the next step?

I don't think there is a way to adjust the linear/offset settings for a 3 bar sensor so it doesn't suprise me that is doesn't run great with one.

Are you still running a MAF or aftermarket MAF?

metal lt1 its not maxed out

There is a scaling factor in the MAP settings which is set to 200 with kPa/256 counts this comes out to 14.3 PSI gauge pressure this is the multiplier used to derive manifold pressure from the MAP by scaling the A/D input by the specified amount of kPa/ 256 counts.

There is also a Sensor offset which is set stock to 7.99. It says this is the offset used in deriving manifold pressure from the MAP sensor.

The Default max kPa is 160 as well.

I really don't know as I am not there on boost yet to worry about it and for 04+ it seems getting the correct technical information is like pulling teeth. These settings are all stock 05' GTP settings.

I know that I have seen as high as 174 kPa on my car which is right at 10.5 PSI gauge pressure. My car is stockish though.


I don't know if you need to adjust the scaling factor or sensor offset or both. I have seen other 04+ tunes with these settings different, but don't know what the car had.

Jeff

Put a stock map sensor in it and post a scan...
What is your plug gap set at?
What kind of wires and coils?

First off go back to the two bar map sensor the GM 3800 v6 PCM First off go back to the tube are map sensor the GM 3800 v6 PCM does not have the ability to run it effectively without a lot of horse trading in other areas.
Second is to check and see if this 15 psi that you're seeing is via scanning software or through an actual mechanical boost gauge with a line running to the intake manifold.
If you're going by the scanning software you will never see over 15 psi
If however you're using a mechanical boost gauge and it is not going over 15 psi then you have an actual issue either with your wastegate blow off valve or a charge pipe coupler

**** my phone

I have no clue what happened but Google voice to text ****en hates me

sounds to me like it will make the boost, just falls on its face at 5100...spark blowout, torque management, icm issue...those are my guesses.

I'd say you have several issues. I make almost 450 to the wheels on 15 lbs, stock heads, st1 cam and 62mm turbo. 9 lbs is like 380 or something. Map doesn't matter, these pcms run on maf. I run 26lbs on a stock 2bar map.

Originally Posted by SlowFiero

I'd say you have several issues. I make almost 450 to the wheels on 15 lbs, stock heads, st1 cam and 62mm turbo. 9 lbs is like 380 or something. Map doesn't matter, these pcms run on maf. I run 26lbs on a stock 2bar map.

he has a lot less turbo they you do though. it does seem a bit low though...hrm...

Z7 kit comes with a 6262 turbo, same as mine, unless he has a old kit before the 6262 was included.

its the older one t3/t04b I think

ok so I haven't seen that you confirmed that this boost reading is from a mech gauge or the oem MAP/scanning

on the 04+ there are maf/map rationality tests (ie it should se max xxx at this psi, if false trigger limp/tq management

lots of nanny features/on board diagnostics (technically its pretty damn near OBD3)

so can you tell us whether it was the scanner or a mechanical gauge that told you that you were not going over 15 psi

Mechanical

are you stock exhaust and is a catalyst still installed?