Quote:
Originally Posted by CanAutM3
Quote:
Originally Posted by Boss330
I was looking for a 100-200 time, but I now understand it's derived from the 0-100 and 0-200 times ��
I wasn't thinking of 0-100 when I mentioned gearing, but the 100-200 times (as that was the ET we where discussing).
From the gear ratio charts we can see that the F82 GTS have to start the 100-200 sprint at 4500rpm in 3rd, changing to 4th at just around 150km/h, dropping down to 5000rpm and revving to 7000rpm at 200km/h in 4th.
The G82 Comp start at 6000rpm in 3rd, changing to 4th at just around 125km/h, dropping down to 5800-6000rpm in 4th, changing up to 5th at just around 165km/h, dropping down to 6000rpm in 5th and reaching 200km/h at 7000rpm in 5th.
How much you actually gain from this shorter rev band in each gear I couldn't say, but probably more than the time lost on that extra gearchange.
For the S55 in the GTS it doesn't seem ideal to drop down to 4500rpm as it only has 400hp there (according to ABS dynograph).
The S58 has a slightly flatter top end curve from 5-7k, but it seem that you wouldn't want to drop much below 6k on shifts on that either. But at least it has over 500hp from 5000-7200rpm, so even dropping down to 5k still gives you more than 500hp.
The S58 makes 400hp at 4000rpm and roughly 450hp at 4500rpm.
I think the better acceleration times for the G82 is a combination of more power (522 vs 492 according to the mag) and closer gearing. Perhaps biggest contributor is the gearing, which is more of a disadvantage for the F82 than a big leap ahead for the G82 (the G82 wouldn't loose much time even if it dropped to 5k during shifts thanks to the S58's power curve).
The G82 is always above 500hp in the 100-200 sprint, while the F82 GTS drops as low as 400hp, due to larger gear spacing, during the same sprint.
The power to weight ratio with ABS' numbers are almost identical btw;
F82: 492/1599 = 0,30769
G82: 522/1695 = 0,30796
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Not quite sure where you are getting your rpm vs speed in gear numbers, but for the F8X DCT shifting 3rd and 4th at 7,500 rpm drops the rpm to ~5,600 in 4th and ~5,900 in 5th. And at 100km/h, the F82GTS is still in 2nd gear at ~7,000rpm.
The tighter gear ratios of the 8AT could be factor in the improved acceleration, but IMO not a significant one. I believe the main difference between the GTS S55 tune and the S58 Competition tune is how fat the power curve is, where the S58C has more area under the curve than the S55GTS, maintaining near peak power level over a much broader rpm band. |
I used the gear ratio charts in the ABS articles (OP and your link).