Quote:
Originally Posted by phunk
OK.... question here to the 7AT guys from a 6MT guy...
instead of worrying about having to up-shift manually and timing with the delay etc.... why not just let the auto trans upshift itself? they dont actually shift any faster in "manual" mode anyway do they? Will someone manually shifting the 370z 7AT actually run down the 1/4 any quicker than the guy just in plain auto mode? i would figure not, and probably slower because hes not going to be able to time it as well.
i mean really, what are you trying to do? no offense, i mean i can understand downshifting the auto manually while coming into a turn or something... but when trying to full throttle accelerate.. what advantage is there to shifting it yourself?
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It's a valid question for drag racing, I guess. But to be honest, if my primary concern was drag racing, I wouldn't have bought a 370 (or a V6 car in general heh). There are probably some fine points to be debated even for straight line acceleration on a standing 1/4. For example, if you got too much wheelspin in first gear in regular D-mode, it might shift to second too early instead of allowing you to play the throttle and get it hooked up before shifting. Of course if you burned all of first gear you're screwed anyways, so meh. Technically there are some minor differences in how fully our torque convertor locks up and at which RPMs (between D-mode and M-mode), but they're minor. Also the car won't pick the same shift point you would. You might raise your rev limiter and be shifting higher than it would choose, or if you have a particularly flat torque curve you might even be shifting back at 7K.
But mostly people who are doing anything serious in a 370Z aren't drag racing, so yeah, we do want to control both the down- and up- shift to keep the revs in the right range, which a full-auto can never do correctly without driver input.
Because 1st gear on the 7AT goes by so fast at full throttle (it's actually even lower geared than the 6MT's first gear, even after the different final drives are taken into account), I have used D-mode for the 1-2 shift from a standing start before. The idea is start in D, floor it, let it shift to 2nd for you, and then flip back over to the paddles to take over and continue driving (e.g. the starting line of an SCCA course).
You can really only do that reliably at a standing start though. Once you're into a course and shifting on your own, there's never really a good time when it would make sense to move back to D, even temporarily. If you did and you were at any less than full throttle, the car would take over with "regular commuter traffic" shifting rules and drop you into too high of a gear for whatever you're doing, and then it gets to be a pain in the *** to switch back and get it back to the gear you should be in.