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      12-23-2006, 02:55 PM   #14
enigma
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Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

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Quote:
Originally Posted by devo View Post
Agreed.

I don't drive on the track but I still want a high revving, high hp motor, with a wide torque band for the street. Contempory sports/GT cars achieve that quite well.

What I don't want is a powerband like the one in your Lotus for street use. You track your cars and obviously track them a lot. So the Elise serves it's intended purpose very well and is a great track car with limited street use; imo.
Its intersting how the BMW and Lotus/Toyota motors differ. Both cars have pretty much the same power to weight. Around town you don't notice either car hurting for torque. For those 20-50% efforts you need both work fine.

Where the BMW excells and the lotus does't is in merging on the highway. The M3 has plenty of power in the 3-6 range. No real stress on the engine but all the acceleration you really need fo anything sane getting on the highway. The Lotus has a crator in its powerband right there so it feels a bit anemic until you hit 6200 at which point all hell breaks lose.

The reason I don't like TQ as a car stat is you cannot tell which behavior you are getting from it.
The M3 3450lbs / 273tq = 12.6
The Elise 1900lbs / 138 = 13.7

A minor but not big diffrence. The big diffrence is most of the M3s TQ is usable over a much wider range. The peak is at 4900 vs 7000. The powerband in the M3 is really about 3000-8000 vs 6200-8000. Getting the car over 3000 rpm is no problem. Winding the elise up to 6200 to go gets everyones attention, including the cops.

A much, much better way at looking at how good a car will be around town is powerband (peak hp rpm - peak tq rpm) / peak hp rpm.

Compare
(7900-4900)/7900 = 38%
(8000-7000)/8000 = 12.5%
This is the real reason BMW is known for there great engines. Plenty of power when you need it while still having more than enough the rest of the time.

The BMW powerband is superior at the track also. There are turns where the lotus falls off the 3rd gear cam but not by enough to justify the shift. In the BMW you would never even notice as you would still be well in the engines powerband.
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