A month or so ago, I posted a brief note about my new racing sprite.
Since then I have run it at the Marque Sports Car Assoc event up at
the Winton racetrack (Winton is i tight and twisty track in which full
race sprites can get to mid 60s in perfect conditions and standard
road spridgets can do low-mid 80s. It is about 200km north of
Melbourne).
The first part was getting it running again -- it saw fit to blow up
its starter motor then the ignition failed (still running lucas
ignition!). Ended up replacing the condensor, rotor (cracked) and
changed the coil to the high performance Bosch unit.
The Prev owner warned me *not* to run the car again on the old slicks
that were on the car. However, I figured that since it was the first
run and I wasn't going to push it... Well suffice to say that it was a
*big* mistake.
The car was undrivable at anything faster than 80s / lap! It was
unbelievably loose (oversteer). I tried tyre pressure adjustment
without success.
One of the other drivers was taking a look at the car and commented on
3 aspects of the rear suspension
1) The back is way too stiff - he suspects that the anti-tramp rods
are binding up the rear end and preventing rear suspension movement
(the rose-jointed rods were not parallel to the leaf springs).
2) the rear axle is moved aft b/n 1 and 2 inches. This is clearly
visible as th ewheel is not centered in the wheel arch
3) the panhard rod is mounted too high (in his opinion) -- he says
that because the bodymount od the PHR is underneath the boot/trunk
floor, the roll axis is moved up to this point and is preventing
weight transfer to the outside wheels.
No 2) is the one that concerns me most -- is there some (incorrect)
way of re-assembling the rear suspension that can cause it to sit too
far back? The car has been lowered and the springs flattened, but none
of the other sprites who have done the same stuff have been affected
in this way.
He wanted to disconnect the anti-tramp rods on th espot -- I wasn't
all that keen as there were simpler things to try first. I first
swapped the fromt and rear tyres and low nd behold, the car
understeered tragically! So, the main problem appeared to be a very
off outside rear (now outside front) tyre. The times dropped to mid
70s but it was still way off its best and very badly pushing
(understeering).
At any rate, it was just as fast as my road car (Honda Prelude Si-4WS
on Dunlop Formula R tyres) and was much more fun to drive even with
the tyre shortcomings.
I am quite keen to see if anyone has ideas on the rear axle
positioning and am looking forward to the next event -- a hillclimb at
Morwell (2.5hrs east of Melbourne). I'll be running on radials,
probably 185/60 Dunlop Formula Rs (D98J) I am leaving the replacement
slicks until later in the year when the weather will be warmer (it is
now winter in Australia!).
The major event for us is the upcoming 6hr relay race at Winton in
Sept (organised by the Alpha Romeo Owners Club of Australia). There
are 5 racing sprites in our team, it will be th efirst 6hr for 4 of
the 5 in the team!
Mike
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