> Subject: Re: 94hp, 1800cc vs 1622cc engine(longish)
> I have been following this thread with some
> interest. Why? Because I am wondering if the B engine
> is as easily tuned to some higher HP than the A
> engine.
>
Howard:
Bill put it pretty succinctly. There is no substitute for cubic inches.
With engines as similar as these (oiling, valvetrain etc.) the only real
difference is going to be bore, stroke, and ability to rev.
Given identical bore, stroke and revs 3 main engine will have more power
available than a 5 main engine as there is less internal friction. This is
assuming the 3 main crank is as rigid as the 5 main crank. Since there is
no such thing as a rigid crank, the difference in power potential will be
reduced slightly by the increased flex of the less supported crank. There
is no way of building absolutely identical engines, so power loss due to
crank flex vs bearing friction loss in a dynamic environment is impossible
to judge accurately.
SOP observation rates the 3 main engine more fun to drive, as there is a
perception of as Bill puts it "a snappier, more free-running engine".
In reality the 3 main 1800 is getting to be a rare bird and the availability
of the 5 main makes it the logical choice for most tuning uses.
Talking of Elva Couriers. I saw an Elva last year at Elkhart Lake that was
fitted with a 5 main 1800, cross flow head, twin Webers and an external belt
driven wet sump oil system. I'm constantly amazed at what passes for a
Vintage Race car.
Kelvin
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|