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Old 12-08-2008, 07:57 PM   #4 (permalink)
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 55.44 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 67.41 mpg (US)
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I agree - sounds like your motor is running "backwards" to how it was originally intended.

The brushes on the motor in the ForkenSwift were originally advanced pretty far:

I was reading up on the pile of EVDL messages ripening in my inbox, and came across a message from motor guru Husted about low voltage systems & brush advance. Noted that he said "5 degrees for mild" voltages. Apparently the common "10 degrees for street use" applies to higher voltages (say 120+). So I went out and measured... and the brushes were advanced (stock) almost 17 degrees!!

Whoops. For 48v he suggested putting them to neutral.

I now have them near 2 or 3 degrees advanced. According to Jim, the closer to neutral timing = more low end torque and less top end RPM. The motor should run more efficiently too. After making the adjustment (drilled a new set of adjustment holes in the end cap ... with the motor still in the car), I can vouch for the first 2 statements. The car goes up hills better (relatively speaking), but I can no longer wind it out to 4000 rpm before shifting - it just runs out of steam.

And it still won't spin the tires on gravel, before or after the adjustment. I tried.
From this post in the FS build thread:

I can't comment on how it may have affected efficiency though. I'm not sure I could test it in a controlled way.
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
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