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Posted by phillip (72.144.187.25) on 22:13:07 03/12/06
I DO NOT want to sound arrogent or anything. This is just a result of boredom and brainstorming.
The thing is, when the latest Car and Drive came out, I was rooting for the S7, remembering the old 2002 Mosler's problems. After reading the recent Car and Driver articles, I suddenly started rooting for the Mosler. It seemed like such a more finished car then before. It finally became the purpose-built track king it was always supposed to be. The only problem I noticed is that 1st gear in the mosler is incredibly large for such a powerful car. The only reason I can see for having such a large 1st gear ratio is for autocrossing, which is not something I envision this car being used for. If a 2nd gear start can pull a 3.1 second 0-60 time, then surely with proper gearing, sub 3 second starts can be had. With a top speed of only 40 mph, I can't really see much of a use 'on track' for 1st gear. In fact, I noticed that every gear is geared towards high accel/low top end.
Are the gear ratios final, or are they customizable? With the current setup, the car is geared for extreme acceleration, even if traction can't be maintained. With 600 hp, speeds in excess of 200 mph shouldn't be out of reach.
Since I had free time on my hands, I drew up another gear stack that would maximize usable power and top speed. Note that these speeds contain a 2.9% correction factor(as it assumes a perfect mathematical circumference for the rear wheel, which doesn't ever happen).
1st:2.45 (67mph @6500) [10.36mph / 1000rpm]
2nd:1.70 (97mph @6500) [14.93mph / 1000rpm]
3rd:1.23 (134mph @6500) [20.64mph / 1000rpm]
4th:0.98 (168mph @6500) [25.90mph / 1000rpm]
5th:0.83 (199mph @6500) [30.58mph / 1000rpm]
6th:0.74 (223mph @6500) [34.30mph / 1000rpm]
Final:3.44 (same as current)
I didn't just design this for a sub-3 0-60. This was purely to give the gears some more flexibility while simultaneously regulating the obscene amounts of power being thrown to the ground. In stock form, 1st gear at 4000rpm is throwing down what equates to 7320 lb-ft of twisting force. It's no wonder that wheelspin occured any time the gas pedal was tapped. With the new gearing, what equates to 4695 lb-ft of torque is put down (which is more than enough to propel the car to 60 in under 3 seconds). Anyone can throw together gear ratios though, but they often don't work well together (upshifts lose too little/too much rpm), so these ratios were set up with that in mind:
RPMs after upshift (at redline),
1st-2nd: 4510
2nd-3rd: 4703
3rd-4th: 5179
4th-5th: 5505
5th-6th: 5795
This is nearly identical to the rpms after upshifts for the stock gearing, except for the 1st-2nd, which in the stock car, is 3685. Each upshift lands you within what I imagined the 'power band' would be (although, with 557 lb-ft at 4000, I imagine the engine pulls strong from any rpm). This also allows a max speed (aerodynamics notwithstanding) of over 220 mph (though speeds of 180+ are rarely, if ever, necissary for tracks *cough*nordshleife*cough* but is usually measured by those looking for a fast track/road car).
Anyway yeah, this is what happens when I see an awesome car and have too much time on my hand. It's actually all illustrated in a pretty extensive spreadsheet which compares all aspects of the stock setup and the revised setup. Call it an excercise 'just to see if I could' lol.
So proud to see a florida-based company excell (IMO) over the 'big names.'
If you've read this far, congrats and thanks for the time!
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