Darn... I hope I was paying attention to which mailing list this originated in:
> Well, to further elaborate on Jim's discussion, here's a question. Suppose
> you have a wide variety of cars from which to choose a street prepared
> autocross machine. Which of the two cars will accelerate faster, GT6 or the
> Spitfire? Which of the two cars will be a killer machine in the 5 to 45 mph
> range?
Mark, isn't it getting a little late in the year to decide which car? :-)
Straying from the subject a little, I'll throw in my two cents of practical
experience with the GT-6, particularly in the 5-45 mph range. If you've got
the suspension sorted out, then the GT-6 certainly SEEMS faster. If you
can't afford to tame the front suspension, then the Spitfire is probably a
better choice, definitely easier to drive.
> For this example, let's say both cars are using 13" wheels with Hoosier
> Autocrossers, 225/45/D13, diameter of 20.7". The Spit runs a rear axle
> ratio of 4.1, the GT6 has 3.89 screws in the back.
Using the Comp T/A 165/70R13 (about 22" diameter on stock rims), I found
the 3.89 diff to be too limiting. I had to put it into second gear most of
the time last year and that didn't leave me as much low-end torque as I
like because it is damnably difficult to downshift to first from second
(the gate runs at a slight angle... miss and you can find reverse, even with
the lockout!).
This year I'll try the 3.27 diff (the non-overdrive diff -- there's at least
_one_ of those laying around here) and trade off a little overall acceleration
for some flexibility. I know it's good for at least 40 mph (3.89 limits
at 35 mph) using a 6000 rpm redline, which is all the stock points can handle.
Electronic ignition easily goes to 7000 rpm, maybe too easily?
Richard, in his Prepared GT-6, found the 3.89 diff perfectly matched the
13x7.5" Hoosier slicks... put it in second and leave it there. They're
under 20" in diameter on 7" rims.
> Feel free to ignore all this, and worry about more mundane things like bugs
> in your teeth, oil spots in your driveway, and so on.
Ah, but how can I ignore one of my pet projects (Celeste, my GT-6 auto-x car)?
--
George Emery - via FidoNet node 1:105/14
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