Little Help..can I use this 85mm mafs?
Trending Topics
10-16-2007, 02:22 PM
#13
Since you're gonna have to tune it anyway might as well. I run a descreened 85mm MAF and a FAST 90. Ofcourse, the 85 MAF is the stock peice on a CTSV. I always thought that if the GM engineers decided that they could make more power by dscreening the MAF on the Z06, then I could too.
Jon
Jon
10-17-2007, 10:18 AM
#16
The output of the stock f-bod MAF per airflow and the output of a stock 85mm MAF per airflow are TOTALLY different.
Your car will run uber-lean, as the MAF will be reporting less airflow than actual and the PCM will restrict fuel to "compensate". 85mm MAF's that are "calibrated" have been tweaked such that the output mimics that of a stock MAF per given airflow and allows them to work without tuning.
If you're going to tune it, go for it, and descreen it. Use the MAF table from the correct truck/'vette.
Your car will run uber-lean, as the MAF will be reporting less airflow than actual and the PCM will restrict fuel to "compensate". 85mm MAF's that are "calibrated" have been tweaked such that the output mimics that of a stock MAF per given airflow and allows them to work without tuning.
If you're going to tune it, go for it, and descreen it. Use the MAF table from the correct truck/'vette.
10-17-2007, 11:06 AM
#18
Sometimes the airflow reported is less than actual, sometimes it's more than actual. It depends on the year of the car/new MAF.
Your car will blend the stock VE data with the MAF readings and calculate the airflow. If the VE is wrong (car is modified) and the MAF is wrong (different than stock), there's no telling what the actual airflow could be. The only thing keeping it even driveable is the O2's who measure AFR no matter what is upstream. They can keep it semi-close, but can only swing the fueling by so much. My guess is that you have a cam, which has overlap, which is introducing air into the exhaust stream, causing the O2's to read lean and commanding a fuel dump to reach what they think is right, but is actually rich.
Every car is different.
Your car will blend the stock VE data with the MAF readings and calculate the airflow. If the VE is wrong (car is modified) and the MAF is wrong (different than stock), there's no telling what the actual airflow could be. The only thing keeping it even driveable is the O2's who measure AFR no matter what is upstream. They can keep it semi-close, but can only swing the fueling by so much. My guess is that you have a cam, which has overlap, which is introducing air into the exhaust stream, causing the O2's to read lean and commanding a fuel dump to reach what they think is right, but is actually rich.
Every car is different.