bjf@homxa.UUCP (B.FENG) (04/16/85)
After Reading the latest "top speed" article, I started to wonder about the comment on 600hp at the rear wheels. Maybe someone out there can educate me on this subject. I had always thought hp ratings for most cars were at the flywheel, and that the hp at the rear wheels was substantially down from the flywheel figure. A case point is that my motor is rated at about 200hp at the flywheel. When the car was on the dyno, the rear wheel hp was closer to 100hp! What gives? How much does the drive shaft/differential design affect the relationship? I'll post a summary. thanks, Feng
davew@shark.UUCP (Dave Williams) (04/18/85)
A considerable amount of horsepower is lost in the drive train
of a car and a loss of 35-50% is not uncommon. The figure of
600 HP at the rear wheels really seems to be streatching the
truth a bit. If the 35% figure is used then the HP at the flywheel
would be ~920 HP! Assuming the 427 was not bored and stroked to
some huge size, this would result in 2.15 HP/cu. in. This seems
to be a bit much. Incidently, who has a 600 HP chassis dyno?
I've been out of the racing business for a number of years, but
the largest I remember seeing was 425 HP.
--
Dave Williams
Tektronix, Inc.
Engineering Computing Systems
"The 6000 Family"
"The workstations that made
Wilsonville famous."