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      08-21-2008, 01:53 AM   #1
M3Rad
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Drives: 2008 BMW M3 DCT
Join Date: Aug 2008
Location: Los Angeles, CA

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M3 DCT vs. 6-speed gear ratios for Track Use

The DCT has very close ratios from 2nd to 6th, I have yet to drive a track where this car could exceed 173 mph, so 7th won't see track use.

1st and 2nd are very similar between transmissions, the gap between these two gears doesn't matter for track use, because I don't know of any track that requires a downshift to 1st.

With the manual transmission, there is a huge gap between 2nd/3rd and 3rd/4th, this must hurt acceleration beyond 75 mph compared to the DCT. Things get closer to even after 150 mph, but it is rare to exceed this speed at the U.S. racetracks.

The engine produces its nicest power between 7,000 rpm and 8,400 rpm, this is the ideal powerband. I would consider a shorter final ratio with a top speed of 170 mph in 7th and 80 mph in 3rd spreading 5 gears across 90 mph.

BMW M3 DCT
Gear / Ratio / Max Speed / RPM drop on upshift
1st 4.780 44
2nd 2.933 71 5200
3rd 2.153 97 6200
4th 1.678 124 6500
5th 1.390 150 6900
6th 1.203 173 7300
7th 1.000 208 7000
Final Ratio 3.154
Redline 8400

BMW M3 6-speed
Gear / Ratio / Max Speed / RPM drop on upshift
1st 4.055 44
2nd 2.396 75 4900
3rd 1.582 113 5600
4th 1.192 150 6300
5th 1.000 179 7000
6th 0.872 205 7300
Final Ratio 3.678
Redline 8400
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