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  1. #1
    64physhy's Avatar
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    Temperature Effects on AFR?

    I do some of my riding in Yuma, AZ with air temperatures well over 100 degrees, and some of my riding in the ocean where the air temp is usually mid 60's. I was wondering how much the temps will affect my AFR. 12.5-12.0 is supposed to be the target AFR for rec and offshore riding, but closed course and hard riding is supposed to target 11.8-12.0. If I set my Powershot to deliver 12.0 WOT in Yuma, is it going to run richer or leaner in San Diego?
    Why is there such a difference in the target AFR for the Yamaha 1.8 and a regular gasoline engine in a Car, which has a targeted AFR of 14.5 for max performance? 13.0 is supposedly in the "danger zone" for the Supercharged 1.8. Is it due to the supercharger?


  2. #2
    Yamaha artisan Cutlass's Avatar
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    14.5 at WOT on the car's I'm used to, is dangerously lean. Most shoot for 12.8 to 13.0 WOT for more power and the OEM tunes are somewhere closer to 12.0 to 12.4 WOT or even richer to be a tad safer.
    Forced induction does like richer WOT mixtures to help fend off detonation and the extra fuel cools things down a bit.

  3. #3
    64physhy's Avatar
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    Maybe the 14.5 isn't for WOT then. Must be for normal driving.

  4. #4
    Yamaha artisan Cutlass's Avatar
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    yes 14.5 to 14.7 is a normal cruising AFR

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