On my quest for tuning my 2008 Cadillac STS-V as I have noted the Camaro5 community discovered that not all examples of the same Hitachi MAF have the same response characteristics. MAFs with a single letter are less responsive than MAFs with a letter-number combo. I believe that this indicator is a ‘lot’ indicator and perhaps relates to the individual components used in the sensor. The STS-V uses the same card-type MAF sensor.
Regardless, I got a ‘better’ MAF in the mail today from Apex Motorsports, and installed it in the STS-V. Unfortunately, the V was heavily heat soaked so it is hard to do much useful testing at the moment. Hopefully I will be able to run some new tests soon.
I did take the V out for a test drive and was able to confirm that the MAF is working properly and no codes shown, etc. with the new MAF in place. I disconnected the battery for the new MAF install, so it has been ‘reset’ again. Ambient temperature will read 32F until it slowly catches up again. The IAT2 temps of 158F show the heavy heat soak, and the IAT1 would rapidly go up when stopped. Local baro from weather underground today was 29.09 in (14.3 psi).
I was able to verify that although the physical throttle angle is 87% the Electronic throttle control system is treating this angle as 100%.
I have been playing with the delivered torque and calculated horsepower on my HP Tuners dashboard. Because these both depend on delivered torque they are not considered useful for absolute value but are debatable to be useful for relative testing. I would say treat them as info the ECM is using for load indication & for fun.