Originally Posted by e36jakeo
I think you guys are overestimating the positive effects of the shorter gearing. As mentioned a 3.62 will add torque 9.5% more torque per gear, but if , say you are going 85 MPH in 3rd gear you will now need 4th gear. 4th gear is taller than the stock 3rd gear, so until the stock 3rd gear runs out it will be pulling harder than the 3.62's 4th gear.
In other words, there is a give and take as to which will be quicker. Overall the 3.62 WILL be quicker, but by no means will it be pulling 9.5% harder at all times. As mentioned above, sometimes it will be pulling harder, sometimes less hard.
Also consider that with super-short gearing you will completely light up the tires in 1st gear, thus sacrificing your launch. So any standing start (without drag radials) will favor the stock car.
Honestly, with how perfectly and tightly geared the DCT is (7 speeds!!) I really don't understand why this is a very desirable option. Really understand the trade offs before getting it.
The 4.10 gearing for the 6-speed MT makes more sense because I find gears 2-4 to be too widely spaced. However, the too-short 1st gear is still a problem.
1)TQ increase of 9.5% is for the 3.45 not the 3.62 wich is about 14%-15%
2) If this is correct,http://www.m3post.com/forums/showthr...ight=3.62+4.10
and if the shift where done at the redline, then no, the forth gear of the 3.62 is not taller that the stock 3rd (DTCs), they are about the same(3mph difference).
3) Wider tires like Sticky mentioned, and/or you can also add a 3 disk carrier and variable ramps(30-90) to the diff.
In any case, this set up will always have significantly quicker acceleration than stock, in the street or track, always. Except in top speed race.