Calgary280ZT Posted April 26, 2010 Share Posted April 26, 2010 I'm currently running 11-12 for AFRs under most loads, though a little richer under higher loads. A buddy of mine is a Nissan-trained tech and a Z32 and Skyline tuner. He says he compensates for Calgary's 3300 foot elevation by running the AFRs around 13-14 under moderate loads, 15-16 for cruising. My next project is to fix my ECU set up so I can read AFRs from the O2 sensor again (currently no signal to aux box) and start logging/tuning again. Thought I would ask you guys about my buddy's AFR #s before I do any tuning. Is he on the money? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 27, 2010 Share Posted April 27, 2010 (edited) ugh error Edited April 27, 2010 by PrOxLaMuS© Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 27, 2010 Share Posted April 27, 2010 (edited) damnit.. my reply didn't post The stoichiometric air/fuel mixture for gasoline powered engines is 14.7. This does NOT change with altitude.. the air density and oxygen levels change with altitude which require less fuel. Even airplanes taking off at sea level and climbing to 18,000 msl need to adjust the air/fuel ratio to aim for the proper AFR/EGR temp for max power and fuel economy. Your car will need to be tuned at altitude, but once again, the AFR numbers will remain the same. 11-12 afr under load/boost, 12-14 moderate loads, 14-16 afr rich/low cruise Edited April 27, 2010 by PrOxLaMuS© Quote Link to comment Share on other sites More sharing options...
Calgary280ZT Posted April 27, 2010 Author Share Posted April 27, 2010 Thanks Prox, good overview for me. So one tune for Calgary, another for Vancouver at sea level. I can handle that. And by your AFRs I can see I'm running pretty rich. Right now I'm cruising at 11-12 and under 11 under boost. Out of curiousity, what do you consider a moderate load? 35% and up? Below or above that? It's been over a year since I last logged a tuning run, but seems to me that even under 10 psi I never went above 42% load. I might be one cell off (maybe 49%), but no more than that. Does that sound right to you? damnit.. my reply didn't post The stoichiometric air/fuel mixture for gasoline powered engines is 14.7. This does NOT change with altitude.. the air density and oxygen levels change with altitude which require less fuel. Even airplanes taking off at sea level and climbing to 18,000 msl need to adjust the air/fuel ratio to aim for the proper AFR/EGR temp for max power and fuel economy. Your car will need to be tuned at altitude, but once again, the AFR numbers will remain the same. 11-12 afr under load/boost, 12-14 moderate loads, 14-16 afr rich/low cruise Quote Link to comment Share on other sites More sharing options...
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