Quote:
Originally Posted by gumba
What fuel head/wur adjustments would you make to compensate for the elevation change? My motor was built and tuned at sea level (Bay Area). At 7,000 ft my a/f's at wot seem to be the same as sea level, 11.5 wot. I recently had a full rebuild on the K27 and was checking the a/f's. I did crank up the boost knob slightly to get up to 1.1.
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Here's what I've seen traveling between altitudes. Idle AFR varied quite bit, but once you cracked the throttle and got some airflow throw the metering plate the AFR's were close to the same, just the curve was offset a little.
This makes sense when you think CIS is just measuring air density by the amount of flow past the metering plate. At idle, it's just a stop screw without much measurable air flow, but once the air flow increases to move the plate it's measuring density. Less dense air, less fuel flow.
I was getting the same WOT AFR's at various altitudes when I adjusted the boost pressure up to compensate for the higher altitudes.
Your 11.5 AFR was at 1.1 bar at 7000 ft? 11.5 AFR at 1 bar sea level? Sounds about the same as my results.
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1986 911 Turbo
3.3L, K27HFS, Tial 46mm, TurboKraft Intercooler, 964 Cams, Monty Muffler, MS3Pro Evo, M&W Ignition, Zietronix WBO2 Data Logger, Wevo shifter, coupler and motor mounts.
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