At 10:16 PM 12/7/2005, John Bange wrote:
>Probably because it's a bit of a pain collecting the conversion factors.
>Converting the variable-voltage output of a hot-wire AFM to the
>variable-resistance output the Bosch ECU expects is probably the easy part.
>Mapping out what voltage equals what resistance sounds like a big pain in
>the butt, particularly because the voltage output of the hot-wire is
>affected not just by the amount of air flow, but also by the temperature of
>the air. ECU's designed for hot-wire AFMs compensate based on the air temp
>sensor. Since the Bosch ECUs in Vanagonsdon't do that, the interface device
>probably has to account for that as well. All I can say is, better them than
>me!
>
>Neat overview of electronic AFMs here:
><http://www.autoshop101.com/forms/h34.pdf>
>They even explain the Karmen Vortex type sensor! Neat.

Ah John you feel my pain!! Thank you for the post... you pretty much nailed
it. We did most of our transfer function testing on our flowbench.. but it
turns out (surprise) you have to do a whole lot of road testing to get
things refined... or maybe I'm too much of a perfectionist.. in any case,
it's taken WAY more to do it than we thought. But we should have it out soon!

Thanks,

Jim

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Bostig Engineering
Engine Systems Voodoo
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978.772.3274
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