I had to think about this one. Providing the diameter of the tire for the
computation is just so the program can determine the circumference. The
circumference, or distance around the tire will remain constant despite the
rolling diameter impact, thus the calculations should be reasonably accurate
when based on actual tire diameters. Am I wrong ?
Mike L.
----- Original Message -----
From: "Ron Osowski" <rosowski@tampabay.rr.com>
To: "M Lempert" <mlempert@bellsouth.net>; "Healey List"
<healeys@autox.team.net>
Sent: Sunday, July 08, 2007 10:11 PM
Subject: Re: [Healeys] High rpm's plus COOLING UPDATE
> Be sure to use the "rolling diameter" of the wheel/tire...measure straight
> up from the ground to the center of the knock-off and double the
> measurement.
> ----- Original Message -----
> From: "M Lempert" <mlempert@bellsouth.net>
> To: "Healey List" <healeys@autox.team.net>
> Sent: Saturday, July 07, 2007 10:18 AM
> Subject: Re: [Healeys] High rpm's plus COOLING UPDATE
>
>
>> Got back from Conclave a few days ago and needed about three days to
>> recover
>> from the ride. It was approximately 2500 miles round trip. Absolutely
>> no
>> cooling issues whatsoever. Got a good test on the way up. I was caught
>> in
>> three traffic jams (as Oritt warned) on route 95 - all in the northern
>> Va,
>> DC and Southern Maryland area. Temps were easily in the 90s, or at least
>> felt that way. The gauge never went above 190 degrees. No vapor lock.
>> During driving, the temperature never went above 160 degrees, and in
>> cooler
>> weather it stayed below that mark. At one point I had lost water through
>> a
>> loose bolt where the generator is bolted to the block (apparently those
>> four
>> bolts go into water). I had actually lost quite a bit of water before I
>> discovered it, but no cooling problems occurred.
>>
>> Now back to the original thread subject... I had estimated my speed at
>> certain RPMs because my speedo has not been recalibrated since replacing
>> the
>> diff with my 3.54. Of course I can't be sure how close to accurate it
>> was
>> even before that. I kept up with traffic very well at 2700 RPM, lost a
>> little ground at 2500 RPM and was in mild passing mode at 3000 RPM - all
>> on
>> route 95 where driving is fast and furious. I figured about 75 MPH at
>> 3000
>> RPM. Now I've checked it out on the web page Nock provided and it seems
>> I
>> was going faster than I thought. It tells me I was doing 81.5 MPH at
>> 3000
>> RPM and 73.4 MPH at 2700 RPM where the car seemed to be very comfortable.
>> Geeze, was I driving that fast ? In my calculations I put the final
>> ratio
>> at .778 (28% OD) and my tire diameter at 25.2" (Vredestein 185/70-15).
>> Does
>> this sound right ? Car is a BN2 with 3.54 rear end.
>>
>> Regards,
>> Mike L.
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