ZR1 Map sensor scaling

[9secVette]

Hi,
I noticed that the ZR1 map sensor is listed as a 2.5 bar sensor, but if you look at the scaling in a stock ZR1 tune file, it is scaled at 312.500.

I have used it in other applications, and found that my KPA is off (100KPA might read 135 +-) which would coincide with the sensor being a 2.5 bar, yet why is it scaled by GM at 312.500 when an older style 3 bar sensor would be scaled at 282?


Anyone come across this?

Thanks for your time.

[Redline Motorsports]

Good question but 312.5 works! Thats all that matters! Maybe its not a 2.5 bar based upon the math!

[gmh308]

There is more to the MAP scaling than meets the eye. The number defines the slope of the MAP response line at a certain voltage somewhere towards 5V that no doubt varies but is not exposed so it depends on other factors like this inc sensor specs and the offset as well.

[Highlander]

I am sure it depends also on the offset. The slope may be high, but if the offset is different it will account to what it should be.

[Meister]

Correct. The same is for the LSJ cobalt motors. The offset + the scaling value combined together provide the proper MAP reading. This is why I am not a fan of just making changes until KOEO MAP reads 100. These numbers are calculated for a reason