Hot weather performance
- Thread starter Jimxb02
- Start date
J
John Richied
Guest
The high humidity with the hot weather does that…
With high humidity the engine actually runs richer…and with a higher temperature the engine runs richer… the combination together kills speed for sure.
With high humidity the engine actually runs richer…and with a higher temperature the engine runs richer… the combination together kills speed for sure.
catfish123
Well-Known Member
- Joined
- Mar 15, 2005
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Interesting, I have never experienced this. At most I may lose 1 mph but the highest speed my boat ever ran was in fairly warm, very humid weather.
whipper
Well-Known Member
hot
In spring UP here when the ice came off I was running 81ish with my 225 promax on a GSE at 2100ft. Yesterday in 100 deg high humitity at same lake and Im a much better driver now 77 was rung out as far as I dare with out blowen out. The huminex index plays a big factor on two stroke engine. In spring water temps cooler, air cooler, lower humidity,engine cooler,= go faster. I would hit 80 10 times a day in spring now I need my 30 on or 28. The 25 trophy still has good grunt all around dont get me wrong and remember that every one else ya race is in the same boat as you.
In spring UP here when the ice came off I was running 81ish with my 225 promax on a GSE at 2100ft. Yesterday in 100 deg high humitity at same lake and Im a much better driver now 77 was rung out as far as I dare with out blowen out. The huminex index plays a big factor on two stroke engine. In spring water temps cooler, air cooler, lower humidity,engine cooler,= go faster. I would hit 80 10 times a day in spring now I need my 30 on or 28. The 25 trophy still has good grunt all around dont get me wrong and remember that every one else ya race is in the same boat as you.
fishnfireman
Well-Known Member
I spend most of the winter fishing down south.
I have seen as much as a 8 mph swing from 40 degree temps to 110 degree with 90 percent humidity.
I just got back from Amistad and had to dropdown in pitch. because of the extreme heat and humidity.
some of the best speeds I have ran with a 225 Pmax. The water temp was about 48 and the air temp was around 40.
I don't think the 280 did as good when the water temps got real cold because the mtr would not build enough heat. but it loves the 55-70 degree water with cool air!!!!!!!!
I have seen as much as a 8 mph swing from 40 degree temps to 110 degree with 90 percent humidity.
I just got back from Amistad and had to dropdown in pitch. because of the extreme heat and humidity.
some of the best speeds I have ran with a 225 Pmax. The water temp was about 48 and the air temp was around 40.
I don't think the 280 did as good when the water temps got real cold because the mtr would not build enough heat. but it loves the 55-70 degree water with cool air!!!!!!!!
you can easily see a 5% HP loss from bad air.
plus you get aerodynamic lift losses from hot air... just ask a pilot of a plane how much carrying capacity he looses on hot, humid days. I would argue that speed losses from aerodynamic lift (packing air under the hull) effects boat speeds more than HP loss
plus you get aerodynamic lift losses from hot air... just ask a pilot of a plane how much carrying capacity he looses on hot, humid days. I would argue that speed losses from aerodynamic lift (packing air under the hull) effects boat speeds more than HP loss
whipper
Well-Known Member
Jimmy good point. I worked with helecopters a great deal and on a good day a Hughs 500D lifts 1000-1100 as little as 8-900 on a hot day in the mountains.
brotherxb03
Active Member
I usually lose about 2 to 3 hundred rpms between the heat of summer and a nice cold front.
fastguy
Active Member
Whipper, how do you race if you are all in the same boat, do you take turns driving, is it a Canadian thing?
George :roll: :roll:
George :roll: :roll:
whipper
Well-Known Member
Same boat
Ya Fastguy that way you never loose but winning is tuff! I ment im sure you know that the heat is effecting every other boat that day aswell so all will be effected by the heat and will have some speed scrubbed off so all is relevent eh. James
Ya Fastguy that way you never loose but winning is tuff! I ment im sure you know that the heat is effecting every other boat that day aswell so all will be effected by the heat and will have some speed scrubbed off so all is relevent eh. James