Quote:
Originally Posted by 767jetz
...I went back and looked at the gear ratio differences between the MT and AT and saw that the AT is geared lower (numerically higher) than the MT which explains why my car feels faster off the line. Most of the perceived increase I noticed in the test car was in the mid range....On a side note, not related to the PK, I also noticed a more pronounced hesitation for the turbo to spool up in the MT, most likely due to the taller gear ratio compared to the AT. I wouldn't really call it turbo lag for fear of starting that debate here on this thread. It was very minor but still it was noticeable. And I've driven cars with real turbo lag, so let's not go there.  |
Somewhat OT... Just discovered this thread...
Thanks for pointing out this fact! (above) In all the back-and-forth about Steptronic vs. manual, "loosing boost during shits", my quoting, over and over again, the SAE technical paper by BMW engineers showing how the prevent the boost from dropping during quick shifts, (retards ignition timing and keeps throttle open) etc... I never looked at the "elusive obvious"
The Auto is geared significantly lower than the manual in first through fourth gears!
I thought it was just a lower final drive ratio for the auto combined with taller gearing in all forward gears. But that's not the case. Here's how it breaks down:
1st Steptronic 15.4% shorter
2nd Steptronic 9.5% shorter
3rd Steptronic 8.0% shorter
4th Steptronic 7.6% shorter
5th manual 2.3% shorter
6th manual 12.2% shorter
So the auto has at least a 7.6% advantage in any gear lower than 5th, and a whopping 15% advantage in 1st gear (plus the torque multiplication until the torque converter locks up). The only place where the manual would have a clear advantage is in 6th gear acceleration without downshifting.
No wonder people on here are saying that the autos launch harder... No wonder the E9x 335i auto is only 0.2 seconds slower 0-60 mph, where in the E46's the difference was 0.5-0.6 seconds, and 0.6 seconds for the E9x 328's.
Or to put it another way: The Steptronic is built for the street, the manual is built for the Autobahn.
OK, back to the PPK...