Another low cost option is to use a rolling road dyno and optimize what you
have.
A few of us have run our road-race cars/engines on special stage tarmac
rallies
for classic cars. They close the best windy country roads and let us go crazy
over stages that vary b/n 3 miles and 20 miles.
Twice now I have used my full race motor. The first time it was an absolutely
miserable pig to drive on the rally. No torque below 6000, no clutch at the
end
of day 2 (3 day event). Gained time in some places, but lost time out of the
slow
uphill corners where the 4.2 diff and 2nd gear were just too tall (this was a
straight
cut close ratio box).
Next time, with the same motor (1293cc, 310 duration cam, almost 0.5" valve
lift,
13:1 compression), the motor was completely different. It still had a power
band, but
it was tractable and would actually pull from < 2000, even in top. It was a
much
better all around package, with heaps more mid-range torque and the dyno said
only about 5% less peak HP.
The difference? Well we adjusted cam timing, ignition timing, choke size (this
was webers) and jetting. We could have adjusted the advance curve for even
better optimisation, but
it was a case of diminishing returns.
Given that the spridget has only 3 usable driving gears (unless you are a gun
double
clutcher who is willing to risk downchanges to 1st gear changes on the move),
there
is a genuine need for a reasonably broad power band. In fact, the car is
faster everywhere
except the real HP race tracks.
I'd suggest that while my experience was with a full-race motor, optimising
cam timing,
ignition timing and jetting is a worthwhile excercise if you want the very
best out of your
motor. Given it is a one-off expense, I consider it very worthwhile and a good
way to
improive the mid-range performance.
Mike
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