View Single Post
      06-03-2013, 09:04 PM   #53
swamp2
Lieutenant General
swamp2's Avatar
United_States
609
Rep
10,407
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Quote:
Originally Posted by CanAutM3 View Post
Thanks for doing this

If we assume DCT, why the interruption in acceleration on gear shifts? Also, why so much wheel spin and lost acceleration going into 2nd? If the car was able to pull 1g in first gear without losing traction, there is no reason it cannot pull 0.75g in second gear. I am guessing that we don't see benefits of the gearing due to assumed shift times and tire slippage shifting into 2nd...

Let me explain why I selected those gear ratios. I reduced 1st gear because I don't think the tires would be able to sustain 1.2g in real life, so I reduced it to slightly above 1g. I also adjusted the spacing between gears 2 to 6 so that the engine always remains in the power plateau, which should yield better theoretical acceleration.
No problem. This is the kind of instant A to B comparisons that actually give the best results using such techniques (relative change more than absolutes).

I agree about the 1.2 g, it is quite high. That being said if the next generation of the Michelin Pilot is out by that time, who knows, just like cars tire tech continues to march on.

Pretty sure the interruption in acceleration is wheel spin.

Again despite the existence of a power plateau, as long as the force curves vs. speed and across gears do not overlap, it still provides better acceleration to shift at redline after a period of rapidly dropped torque.

Quote:
Originally Posted by CanAutM3 View Post
Agreed that it all comes down to power. Peak power is a great way to quickly assess overall performance. But ultimate performance is about average power produced during an acceleration run, not only peak power. IMO, this is why the power plateau will make the M3/M4 performance impressive.
But not nearly as impressive if the plateau did not exist in the first place due to the turbo and or Valvetronic systems not being able to breathe like a high performance NA engine can!
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |
Appreciate 0