1986 944 Turbo gearbox

[Jad]

The way the rules read, boost is 6 points. No limit on boost. At 3 bar you could have 500+ hp for 6 points, money and reliability will be issues, but that would be a monster car.

Basically, everything has trade offs, so there is no one best answer. Fontana would be much different than an AX as well.

Paul:

Very curious as to how you got the precise numbers? Even with full data systems I have never gotten anything accurate to hundredths of a second consistently?

[pdy]

Jad:

Simple (relatively) calculations.

Cars are governed by the laws of physics
(although I too am a fan of fewer laws )

I have been doing computer simulations of car
performance for 20+ years. I use some basic
kinematic equations to calculate the cars'
straight-line performance. One result is the
familiar acceleration curves published by car
manufacturers and enthusiast magazines.

Knowing the engine curve (either Torque or Power)
I can build a model of that curve. I also use
the gear ratios, tire size, weight, and the
aerodynamic info (area and Cd). With all this
I can simulate the performance. The results
match the published data for dozens of cars
that I have done (the match is very close).

While I don't have GPS based DAS in my car,
I did time segments of video from Fontana.
That data also matches my car's straight-line
performance to within 0.3 sec on the oval,
and for the longest infield straight.

It is easy to make virtual modifications and play
the "what-if" game - remove 100 lbs, change the
gear ratios, widen the body (aero), etc.

Again, it's all governed by physics (maybe
not simple, but reproducible) which can be
represented by equations. And the real-world
and published data supports the virtual data.

It would be interesting to take a properly
instrumented car and try different rear tire
diameters. Although at higher speeds, the change
in height and rake may affect performance slightly
due to aerodynamics, I know it will correlate well
to my modeling program. This would prove to those
who doubt physics that shorter R&P is only of
benefit right off the line, or if it happens to
match better to a given track.

As a driver, there is a fairly large perception
of "being in the right gear", so changing to a
different Ring & Pinion will be rather noticeable.
I have experienced this myself many times, and
for me Fontana has a couple of turns where I feel
like I need a bit more RPMs. Here a lower R&P
might help (but then I'd run out of gear on the
oval). Other tracks I found I had to upshif at
points where previously I could hold a lower gear.
See, it all depends.

Regarding you (Jad) not being able to keep up with
me in the infield of Fontana with your old 951
Batmobile, that's BS! At autocrosses, you and
that car got enough BRI and top finishes to prove
it does very well in the slower stuff, thank you.

[Jad]

Paul, I was not trying to imply I couldn't beat you in the infield, just that if you were 12 MPH faster on the oval (about 10%), you would have been at LEAST 2-3 seconds faster on the oval part which is about 1 minute. Overall I beat you by 9 seconds, so if you beat me on the oval by 2-3, I would have had to beat you in the infield by 11-12 seconds, which I really doubt since the infield is also about 1 minute. I think it makes much more sense that I beat you by a few seconds in both areas and that is what I was trying to say.

I guess for anyone who is still reading, my main experience comes from never having been TTOD with the stock gearing, to having 2 TTOD's out of 3 tries with the short gearing. Not scientific, but enough that I thought it was 6 points very well spent.