Weight and Horsepower
#17
Rennlist Member
#18
Rennlist Member
So, lets see if" the comedians in our midst" has the answer for the follow-on racer tech question.
What is the effect of 5lbs of wheel weight as far as HP cost, for straight-line acceleration at any speed using Winders handy formuals?
https://getyarn.io/yarn-clip/b318236...0-1619177c7191
What is the effect of 5lbs of wheel weight as far as HP cost, for straight-line acceleration at any speed using Winders handy formuals?
https://getyarn.io/yarn-clip/b318236...0-1619177c7191
#20
The Penguin King
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Rennlist Member
http://youtu.be/y2R3FvS4xr4
#23
Rennlist Member
Interesting that the group that condemns the "Derailing" a thread", makes up more than 11 of the 21 posts so far, (more than 50%) with insults and attempts of humor.
Im curious; Is thread having to do with math similar to the effects of feeding the gremlins after midnight?
Im curious; Is thread having to do with math similar to the effects of feeding the gremlins after midnight?
#24
WRONGLY ACCUSED!
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Not to be crass but I always try to take a big dump before a race because it can be an extra 1HP. Put that into one of your formulas!
#25
Rennlist Member
Scanning it quickly but I didn't see a reference between sprung and unsprung weight either.
#30
Rennlist Member
While we are at it, what about changing wheel diameters. I used the app that ProCoach pointed to in the 'when to shift' thread (I think that's where he referenced it) and calculated my speed at shift points with 20" and 19" rims.
As an engineer it seems that if the same car has a lower top speed due to a smaller radius wheel then it is getting there quicker thus feeling like more HP. Is this correct? If so, then the resulting ratios change my 400HP to 415HP when I change from 20" rims to 19" rims (similar tire profile on each 295/30/R19 or R20).
20" rim (27" tire), 3rd gear max calculated to 112.8mph
19" rim (26" tire), 3rd gear max calculated to 108.7mph
(108.7 / 112.8) = 0.96365 (I got this same ratio regardless of the gear)
(400HP / 0.96365) = 415.087HP
Does this math work? Or is it the other way around and I get less horsepower (intuitively it seems like it should be more)? Less torque results in more HP.
As an engineer it seems that if the same car has a lower top speed due to a smaller radius wheel then it is getting there quicker thus feeling like more HP. Is this correct? If so, then the resulting ratios change my 400HP to 415HP when I change from 20" rims to 19" rims (similar tire profile on each 295/30/R19 or R20).
20" rim (27" tire), 3rd gear max calculated to 112.8mph
19" rim (26" tire), 3rd gear max calculated to 108.7mph
(108.7 / 112.8) = 0.96365 (I got this same ratio regardless of the gear)
(400HP / 0.96365) = 415.087HP
Does this math work? Or is it the other way around and I get less horsepower (intuitively it seems like it should be more)? Less torque results in more HP.