Boost Data Log for Turbo Cars Question

[Blue03Si]

Hi! I just recently became a LapTimer Petrolhead edition for android user. I used it this last weekend to data log an autocross in my 2015 Subaru STI via OBDLIMK MX via Bluetooth. I was going through my data-log from the runs and was trying to figure out how to convert the data from the MAP sensor to PSI boost/vacuum and am completely stumped. I Googled a bit trying to figure it out but nothing seemed to correlate. Am I missing something? Is there a way to log turbo boost/vacuum in any other format than the default MAP numbers?

Thanks!

[Harry]

MAP is coming as a one byte value between 0 and 255 corresponding to 0 to 255 kPa absolute pressure. Atmospheric pressure is around 100 kPa (depends on weather conditions and height), so the relative pressures range is between - 100 kPa and + 155 kPa. To convert to psi, use 1 pound per square inch =
6.89475729 kilopascals

Harry

[Harry]

Need to check, but LapTimer probably uses Bar for MAP export with 1 Bar = 100 kPa

[Blue03Si]

Need to check, but LapTimer probably uses Bar for MAP export with 1 Bar = 100 kPa

Thanks Harry! I really appreciate you taking the time to answer me. It looks like you're right, its in Bar. The part I was missing was to subtract out 1 atmosphere in my conversion. If I multiply it by 14.5 then subtract out 14.5 it looks more like what I expect for my RPM and throttle position.

Eg.
MAP - 1.74; Boost - 10.73
MAP - 1.99; Boost - 14.35
MAP - 2.22; Boost - 17.69

If I'm missing something let me know, but I think it got it.

Thanks again!

[Harry]

Yes, that's sound.