thought I had AFRs set, then the cold days happened
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thought I had AFRs set, then the cold days happened
Ive been working on getting my AFRs set using my Innovate LM1 wide band with datalogging and LM2 rpm module. I am tweaking my engine management systems second power level settings using 12 psi primary turbo and 13 psi secondary turbo.
The weather here in the Northwest had been warm and sunny with temps in the high 60s to mid 70s. The coolant temp averaged 200 deg F with intake air temps at about 100 - 120 deg F. Low load AFRs were at 12.5 with 13.5 at idle. Medium to high load AFRs were running 12 to 11.5. Boost ranged from 11 - 11.5.
Then we got a few days of clear very cold weather 35 deg F with no wind chill factor. Engine temp was now running at about 165 - 175 deg F and IAT at about 80deg F. AFRs went to 11.5 to 9.5 range. I havent played with temp compensation yet but it seems a radical change.
Another issue that has been a major pain is getting the 3500 rpm - 4500 rpm range set. When I have what should be ideal settings, I get a stutter under low load but pushing the throttle more seems to overcome this phenomenum. I remember reading something about what happens in this rpm range having to do with secondary turbo coming online and transition from primary throttle port only to both primary and secondary throttle ports opening up.
Any input would be appreciated that would broaden my understanding of these issues and perhaps some insight into ways to address these problems.
thanks
-chuck
The weather here in the Northwest had been warm and sunny with temps in the high 60s to mid 70s. The coolant temp averaged 200 deg F with intake air temps at about 100 - 120 deg F. Low load AFRs were at 12.5 with 13.5 at idle. Medium to high load AFRs were running 12 to 11.5. Boost ranged from 11 - 11.5.
Then we got a few days of clear very cold weather 35 deg F with no wind chill factor. Engine temp was now running at about 165 - 175 deg F and IAT at about 80deg F. AFRs went to 11.5 to 9.5 range. I havent played with temp compensation yet but it seems a radical change.
Another issue that has been a major pain is getting the 3500 rpm - 4500 rpm range set. When I have what should be ideal settings, I get a stutter under low load but pushing the throttle more seems to overcome this phenomenum. I remember reading something about what happens in this rpm range having to do with secondary turbo coming online and transition from primary throttle port only to both primary and secondary throttle ports opening up.
Any input would be appreciated that would broaden my understanding of these issues and perhaps some insight into ways to address these problems.
thanks
-chuck
#3
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Originally Posted by kuroi FD
It should lean out when its cold because the intake charge is more dense if im not mistaken
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ncds_fc
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08-15-15 10:06 AM