Re: Speed Application

[Khan Klatt <kmk@pacificrim.net>]

At 4:43 PM -0400 10/15/98, VWDrvrsWtd@aol.com wrote:
>In a message dated 10/15/98 2:26:40 PM Central Daylight Time,
>piecuch@hsd.utc.com writes:
>
>> So, let me get this straight....
>>  Let's sample Top speed.
>>  205/50 R15 at 6500RPM in 5th gear on a Jetta GLX
>>
>>  TD = 23.08"  (Stays the same)
>>  MPH = (6500 * 23.08)/(0.84 * 1000)
>>  MPH = 178.6   WOW!!!!
>
>What, yours doesn't go that fast?  :)

I'm sure mine would go that fast, if it were on a dyno. Add the wind
resistance (our cars are no formula-1 racers) and other factors (perhaps
road friction, etc.) and your road efficiency will be reduced.

You could add a "efficiency" factor to this calculation, on a sliding scale.

At first gear, multiply your speed ratings by 0.95, to get "real world"
numbers.
In second gear, multiply your speed calculation by 0.9 to get real world.
In third gear, multiply by .85 to get real world speed.
In fourth, multiply by .80,
and in fifth, by .75 to get real world speed.

That would produce roughly 135 mph, at 6500 rpm in fifth gear, adjusted for
"real world efficiency" by my rough "adjustment" factor.

-Khan
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Khan Klatt <kklatt@nw.verio.net>                                       Verio
Network Engineer                                    Bellingham Branch Office
Tel 800.591.2757 x 13                                    725 N. State Street
Fax 360.738.8315                                        Bellingham, WA 98225

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