Any forced induction guys that use HP Tuners read

[99-LS1-SS]

As most of you guys know the stock LS3/L76 MAP sensor only reads to 120 kPa which is roughly 2.5 lbs of boost. I have found a MAP sensor that will read up to 312 kPa and it is a direct plug in. The only thing you have to do is adjust the MAP voltages to match the LS9 motor. These settings are found under Engine Diag > Airflow > there are 4 MAP sensor settings that you adjust.

Greg at Pace sells these sensors. They take a week or so to get in because there aren't a lot of them but if you want to know your boost exactly, then it's worth it.

The part number for the MAP sensor is 12592525.

Here are the 4 tables that you adjust.

Here is a screen shot of my current (LS3) MAP data.
http://www.usamls.net/brandon/images/ls3_map_data.jpg

Here is a screen shot of the ZR1 (LS9) MAP data pulled from a stock ZR1 file.
http://www.usamls.net/brandon/images/ls9_map_data.jpg

If you get the sensor, here is the formula to convert kPa to PSI.


(kPa - 101.325) * .1450377 = PSI (boost)


In my case it is:

145 - 101.324 = 43.675 kPa

43.675 * .1450377 = 6.33 lbs of boost

[Patrick G]

This is good info if you plan on running speed density with no MAF, but with the MAF scale reading as high as it does, it may not be a necessary step for all. Good intel though.

[99-LS1-SS]

I am actually going to attempt to start tuning my VE. I can't decide if I want to get the upgrade OS or use the EQ <> VE Version 3.5 that Bluecat started and Ktoonsez modified. Just to save a little money, I'll probably work on the virtual VE table with the EQ <> VE program and see where that takes me.

Patrick, what's your take on running a mix of speed density and MAF?

[Patrick G]

Patrick, what's your take on running a mix of speed density and MAF?I like tweaking the VE tables in speed density before I rescale the MAF. Having both tables working together makes transitional fueling so much better. The VE lookup table is a nice sanity check for the MAF which can get freaked out a lower rpm with things like camshaft overlap and boost coming on and off. The MAF is exceptionally accurate at higher airflow numbers though. I trust it more than VE at higher rpm.

[bbradyc5]

I don't recall on my dashhawk, but do you know offhand if a dashhawk can read/display this boos value if the sensor is swapped out with the LS9 one? .... would be nice if it could instead of having to mount a separate boost gauge.

[99-LS1-SS]

It won't work like that unless you alter the voltage setting in the cars OS.

[99-LS1-SS]

I like tweaking the VE tables in speed density before I rescale the MAF. Having both tables working together makes transitional fueling so much better. The VE lookup table is a nice sanity check for the MAF which can get freaked out a lower rpm with things like camshaft overlap and boost coming on and off. The MAF is exceptionally accurate at higher airflow numbers though. I trust it more than VE at higher rpm.

Do you upgrade the OS or use another method and adjust the virtual VE tables?

[Patrick G]

Do you upgrade the OS or use another method and adjust the virtual VE tables?It's standard OS when you have EFI Live. It's one of the program's most valuable features.

[99-LS1-SS]

It's standard OS when you have EFI Live. It's one of the program's most valuable features.

Dang it! You're going to make me buy EFI Live now.....

[Darkmanx]

so whats everyone else doing to read boost? do they just leave it be? sorry im a noob

[99-LS1-SS]

You can hook a mechanical boost gauge to your boost/vac line and that should help you. I don't want to put gauges in my car so I'm going with the electronic way.

[bbradyc5]

Is this something that is feasible with the common tuning softwares out there or is this something requiring som GM LAN hacking?


It won't work like that unless you alter the voltage setting in the cars OS.

[99-LS1-SS]

Is this something that is feasible with the common tuning softwares out there or is this something requiring som GM LAN hacking?

It's a very simple change in HP Tuners and I have to assume it's easy in EFI Live as well. As far as the tune goes, you are, literally changing 4 numbers.

[bbradyc5]

When using online conversion calcualtors, it is showing that 120kpa = 17.5 psi??? ...what am I missing here?


As most of you guys know the stock LS3/L76 MAP sensor only reads to 120 kPa which is roughly 2.5 lbs of boost. I have found a MAP sensor that will read up to 312 kPa and it is a direct plug in. The only thing you have to do is adjust the MAP voltages to match the LS9 motor. These settings are found under Engine Diag > Airflow > there are 4 MAP sensor settings that you adjust.

Greg at Pace sells these sensors. They take a week or so to get in because there aren't a lot of them but if you want to know your boost exactly, then it's worth it.

The part number for the MAP sensor is 12592525.

Here are the 4 tables that you adjust.

Here is a screen shot of my current (LS3) MAP data.
http://www.usamls.net/brandon/images/ls3_map_data.jpg

Here is a screen shot of the ZR1 (LS9) MAP data pulled from a stock ZR1 file.
http://www.usamls.net/brandon/images/ls9_map_data.jpg

If you get the sensor, here is the formula to convert kPa to PSI.


(kPa - 101.325) * .1450377 = PSI (boost)


In my case it is:

145 - 101.324 = 43.675 kPa

43.675 * .1450377 = 6.33 lbs of boost

[norm8332]

When using online conversion calcualtors, it is showing that 120kpa = 17.5 psi??? ...what am I missing here?

It's only 2.5 psi boost to us in a 15 psi world.

[99-LS1-SS]

When using online conversion calcualtors, it is showing that 120kpa = 17.5 psi??? ...what am I missing here?

You have to subtract 14.69 for the atmophere.

[bbradyc5]

DUhhhh.....thanks guys, I amaze myself sometimes ;)
You have to subtract 14.69 for the atmophere.

[Darkmanx]

so what happend to the pics of the 4 settings i need to change , i want to read boost off my hptuners instead of installing a unecessary guage

[meatbag]

Here is the 3Bar Bosch Style MAP sensor for the LS3/L76 Style Intake Manifold. Part Number 12592525.

http://www.atvci.net/~jcevanco/images/LS3_3BAR_MAP.jpg

Thanks to RWTD for the Calibration Data.

Linear: 312.50
Offset: -11.25

[Darkmanx]

Now to find somewhere that has them in stock