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  1. #1

    The effect of air conditions on ECU, RPM, performance, and top speed

    Brand new 310 ultra went 72.6 mph at 8000 air temp 55 water temp even colder. Today was 85 degrees and crazy humid and I struggled to break 69 mph at 7500. Anyone else have this happen? I assume the ECU does this?


  2. #2
    Mod less, ride more! troyheb's Avatar
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    Humidity kills power more than anything.

  3. #3
    Ya, I thought so. I'm just surprised it keeps the RPM down from 7800-8000 to 7500-7600

  4. #4
    "just sayin".. jetdave56's Avatar
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    Don't sweat it..

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    "just sayin".. jetdave56's Avatar
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    Yep,I keep a weekly data log of air temp/humidity at the time on the water plus water condition,mods,top speed and rpms/boost etc..

    You may see a 150-300 rpm and 2-3 mph loss with very high humidity with these forced induction engines, I certainly do but before you hit the panic button try testing in the same body of water on a cooler day in the morning and note humidity level something below 50% would be ideal and take readings..

    Living in the Northeast part of the US the best riding might be the middle to late Autumn Oct., air is dry with low humidity and air and water temps are still very bearable 60*/40-50%H with water temp around 55-60*

    Overall that's why intake and exhaust air mods are discussed on here and the best way to keep the engine bay cool for less performance loss..

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  7. #6
    Cool thanks guys

  8. #7
    nicjak's Avatar
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    yep been same since the 250's air temps and pressures change everyday thats why oneday you will run 75+ then the next you wont

  9. #8
    Interesting

  10. #9
    as others I've said, humidity is the killer, especially with forced induction engines. For every bit of water the blower sucks in, thats oxygen that its missing out on. I'm not familiar enough with the ECU system on your ski, but one of 2 thins happens. The ecu either reduces the fuel to counteract the loss of air, or it doesn't, resulting in a rich mixture. Either way, it equals a loss of power. A trip to the pits at the drags and you'll see the racers changing jets as the air 'comes good' at night.

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  12. #10
    Cool

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