[MidlifeCrisis]

I've been messing with the boost pressure in ST lately and have noticed that I cannot seem to get a boost value higher that 18.42 psi in the logs no matter what I do to the WGDCs or boost targets. It'll get to that value in the 4000 RPMs and stay there until the RPMs rise past 5500 or so, depending on the gear. The turbo is big enough to go a lot higher. Butt dyno says it is going higher.

Here's a second and third gear pull:



Here are some relevant maps that were loaded:








??? Does anyone know if there is a pressure limit for the stock sensor? Is it a PSIA or PSIG device? I'm seeing 0.13+ MPa on the stock boost gauge on the steering column.

Do I need an AVC-R or something else to use and control boost pressures in the low-mid 20s where I want to be (race gas)?

Am I missing something else altogether here?

FWIW, the baro sensor up here is typically logging at around 24 inches H2O at 5700 ft MSL or so.

-Bruce

[MidlifeCrisis]

Just the answer I was hoping for. I will switch to logging absolute pressure and barometric pressure and calculate the difference in the spreadsheet.

Any idea where the absolute pressure sensor tops out? I have heard it is somewhere in the low 20s (boost at sea level), which would be about 35-38 psia.

[Siegel Racing]

Absolute won't read over 37 psi

SS

[MidlifeCrisis]

Nick - indeed you are right.

I'm a much happier camper now.



Scott - thank you. This means I should be able to control boost up to 23-4 psi up here using the stock sensor and StreetTuner. My faith in the utility of ST for significantly modified engines is restored. By the way, when are you coming this direction again? Somehow I missed you on your last trip to CO. Need an all expense paid ski vacation?
-Bruce

[Nixlimited]

Is it normal for AFRs to go so rich right has you go from 81 TPS to 100 TPS? 9.xx is really rich!

[MidlifeCrisis]

I don't know about normal, but I intend to tune that out.

In this particular case, I have not touched fuel or ignition yet. They are still at whatever the COBB Stg 2 V1.10 StreetTUNER base map had. I have only worked on injector scaling and intake calibration so far and am now playing with the boost. I may end up addressing that with addtional injector scale changes initially, then look at tip-in enrichment and finally go to the primary fuel map to make it all right. Too rich is OK right now because it is relatively safe while I am dinking with boost.
-Bruce

[Nixlimited]

Originally Posted by MidlifeCrisis

I don't know about normal, but I intend to tune that out.

In this particular case, I have not touched fuel or ignition yet. They are still at whatever the COBB Stg 2 V1.10 StreetTUNER base map had. I have only worked on injector scaling and intake calibration so far and am now playing with the boost. I may end up addressing that with addtional injector scale changes initially, then look at tip-in enrichment and finally go to the primary fuel map to make it all right. Too rich is OK right now because it is relatively safe while I am dinking with boost.
-Bruce

Cool, I am trying to learn all about it because I am going to get ST soon.