While going up through the gears,
I could feel a bit of a 'bump' as if the rollers were off center...
of course the rollers were fine -- it was my wheels or rather
tires that were a bit out of round. I was reassured by the operators
that this was common even with more exotic machines, particularly
as the tires were cold as the rest of the car. Eventually the
tires warmed and the 'ride' smoothed, but I noticed a grin and
some pointing at my rear wheels by a bystander. Sure enough,
leaning over and peering out the passenger side, I could see
that the wheel had a bit of 'wobble' as well. So much for those
original Triumph Herald rims -- at least I have a spare! Didn't
look like a problem serious enough to sweat over, so I went ahead
and held my speed at 3500 RPM until I was given the sign to step
it on up 500 revs. I held the revs at 4,000 and 4,500 until I
was given the sign that the reference reading had been taken,
then let the car slow down again and put it back into neutral
and idle for a few minutes.
Now, when I'm out on the road,
I've seen a bit over 5,000 in spirited acceleration, but I never
felt that there was much more power up there. I was also still
acutely aware that the car had spent the night before in sub
zero (Fahrenheit) and was just a bit nervous about pushing it
too hard. generally I figure if I'm gonna break the car, I'd
prefer to do it on a race course (though I suppose it would be
safer on the dyno, they'd probably bill me for the clean up!!)
So for our first dyno outing, I kept a 4,500 rpm limit.
Now the real fun begins... I'm told that
the operator will spin up the dyno so that the rollers drive
my wheels at the speed which corresponded to the reference RPM
we captured earlier. At 3,500 RPM that translates to 49mph though my speedo tells me I'm at 60mph ! I've always heard that a Seven feels faster than
you're really going, but I didn't realize my speedo was THAT
far off! Anyway, so here I am at idle with the road speed at
about 49 mph. Now the trick is to bring the revs up to the predetermined
3,500 RPM, push the clutch, select 4th gear, and let the clutch
up slowly while while throttling the engine up precisely to the
RPM matching the road speed. Sort of the opposite of those TR7
"Shape of things that win" commercials back in the
80's -- you remember, where the TR7 cruises up to the back of
the semi trailer with its ramp down and drives on up, the wheels
skidding somewhat as they go from road speed to crawling up the
ramp... never mind.
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