AFR and KPA different in 3rd versus 4th gear
06-15-2014, 10:35 AM
#1
AFR and KPA different in 3rd versus 4th gear Something I noticed this morning doing a 2-3-4 pull. My AFR was 11.0-11.2 in 3rd gear and 178kpa on the MAP. In 4th gear it was 10.7-10.8 and the MAP was only 165kpa. Boost was basically a flat line from 6000-6800 in 4th. I was between 160-165kpa in that range. Is it that the blower is maxed out and that's all she's got in her? Since it's less boost in 4th gear does that explain why 4th was richer? I'm driving the blower 10% past rated impeller speed.
06-15-2014, 05:31 PM
#4
On The Tree
Join Date: Aug 2011
Location: Indiana
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MAF tunes typically will run richer by a few % in the higher load gears. I street tune in third on the money and see a few % richer in fourth also. It's not going to hurt a thing, may save the engine in the long run during the 150 mph speed runs. 
Most tunes switchover to MAF between 3k & 4k rpm. I switchover >800 rpm.
Most tunes switchover to MAF between 3k & 4k rpm. I switchover >800 rpm.
06-15-2014, 06:07 PM
#5
MAF tunes typically will run richer by a few % in the higher load gears. I street tune in third on the money and see a few % richer in fourth also. It's not going to hurt a thing, may save the engine in the long run during the 150 mph speed runs. Most tunes switchover to MAF between 3k & 4k rpm. I switchover >800 rpm.
Most tunes switchover to MAF between 3k & 4k rpm. I switchover >800 rpm.It's a brand new motor. Less than 400 miles on it now. I have to break it in how I'm going to use it.
