Jim:
I am not so sure about the weight of the car being irrelevent at top speed.
I seem to remember seeing a clip of Cale Yarborough demonstrating that a
brick can fly as his stock car took off like a bird at 200 mph when the wind
got underneath. Seriously though, without sufficient weight, the wheels are
just going to spin rather than go any faster when the static friction on the
ground equals the wind pressure times cross-sectional area times drag
coefficient.
Mark Hooper
1972 TR6 (not in danger of either flying or skidding due to excessive power)
-----Original Message-----
From: Jim Hill [mailto:jrhill@chorus.net]
Sent: Monday, February 24, 2003 3:47 PM
To: 6-Pack
Subject: Re: Bench racing
Steve Bridge wrote:
> I've done some checking in my TR8 manual and the OD
> is actually .833, not .78.
> Now how fast am I going with the 3.7?
127.4 mph.
But ONLY if your postulates are accurate:
~ The true "rolling diameter" of the tires at that speed is indeed 22"
(the tires may expand due to centrifugal force, increasing the effective
rolling diameter).
~ An overdrive ratio of .0.833
Speed = (RPM * TireDiameterInInches * 0.002976) / ( RearEndRatio * GearRatio
* OverdriveRatio)
> The car could also be reduced down to 1300 lbs.
Weight is virtually irrelevant to top speed. Frontal area and shape DO
matter.
Jim Hill
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