Doug,
Not a simple thing. Some losses tend to be directly proportional to
transmitted power -- like gear mesh losses, bearing losses. Other losses
are proportional to speed -- like oil windage. Some losses are pretty much
fixed, regardless of the transmitted power -- e.g. seal friction would be
about the same for gearbox seals, axle seals, etc in a 600 HP Trans Am car
as they are in a 100 HP small-bore production car.
In general, I'd expect a larger HP/slower RPM car to be more efficient (have
proportionally lower losses) than a small HP/high RPM car, like, say,
f'rinstance a Honda S800 ...
Sorry!
Mark Palmer
>From: S800Racer@aol.com
>Reply-To: S800Racer@aol.com
>To: brian@uunet.ca, ralph@cloverleaf-auto.com, vintage-race@autox.team.net
>Subject: Re: horsepower
>Date: Mon, 13 Nov 2000 12:43:16 EST
>
>In a message dated 11/13/00 9:16:09 AM, brian@uunet.ca writes:
>
><< How about 15% loss for a Hewland( rear wheel drive, all straight cut
>gears), up to 20% loss for typical rear wheel drive helical trans, >>
>
> I've often heard the 15 - 20 % "rule of thumb". Is this true
>regardless
>of HP? If a 100hp vehicle lost 25hp, would a 500hp vehicle lose 125hp?
>Wouldn't it take roughly the same # of HP to drive similar Trans & rear end
>gears regardless of the HP of the engine?
>
> Doug Meis
>
> P.S. Would a hand count necessarily yield a more accurate result?
>;-)
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