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      02-15-2008, 12:17 PM   #107
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Drives: Legacy GT - 13.704@99.39
Join Date: Jul 2007
Location: Manheim, PA

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Originally Posted by swamp2 View Post
Bruce you don't really need me to tell you this do you? Again all of these things may or may not have been achieved or may have been achieved in varying degrees in the M3. Furthermore, there are certainly some counter examples to these points meaning they are not absolutely/universally true.
  • Power to the ground per weight is key. High rpm engines generally develop more power than lower revers (all other things equal)
  • High rpm engines can hold gears longer than low rpm designs, which when all other things are equal will produce a faster car
  • Throttle control and precision is enhanced with high rpm designs
  • High rpm designs can be made to withstand less torque and can therefore be lighter.
  • High rpm engines can provide more hp/l which can offer improved efficiency and emmissions for a given power
  • High hp/l engines can avoid costly taxes in some countries based on displacement
  • High rpm engines are darn fun and sound heavenly, let's not forget the importance of these somewhat subjective points
  • Lastly what about F1 cars? Yeah I know, the GT-ish M3 is not an F1 car but there would be no way to get these to perform the way they do without very high rpms and gears to match.

I too would like more information on European engine weight standards. I would expect all manufacturers to follow the regs if they exists. Does it makew fundamental sense to you that a 4l and 6.2l engine of more or less the same design can weigh very close to the same?
OK, look. I tend to agree in concept on all points you list (except the third and fifth), but that's all food for thought in some other fairly esoteric string. The thing is, you wrote:

Originally Posted by swamp2 View Post
A DOHC design carries some extra weight up top and that is a small draw back of its deisgn. However, the redline of the M3 is quite stupendous. Your post above is a bit dismissive of the value of a high rpm engine. The Vette engine is not absolutely better in all regards, hands down.
In response to that I asked what the value of a high rpm engine was, and since I wasn't specific, you gave me the general answers.

So-o, in that context, with the LS3 and M3 engines having similar weights and overall sizes, and the LS3 having power and torque advantages (plus possible bsfc advantages), specifically what is the value of the M3's 8400 rpm red line vs the 6500 rpm red line of the LS3?

The more I think about it, the more I'm beginning to believe that the LS3 really is "absolutely better in all regards, hands down". I'm perfectly willing to be disabused of that notion, however, so fire away, and maybe I can learn something.

Thanks in advance,


PS - I really am perfectly willing to believe that the Mercedes and BMW engines have similar weights, on general grounds that there are DIN/EC standards for such things, but also on technical grounds that the Merc and bimmer motors are built to differing engineering standards, very possibly of different grades of aluminum. The Merc engine, offered in larger volumes than the BMW unit across several different car lines (therefore amortization costs are lower per unit), still goes for $56K over the counter - so it really may be made of unobtanium.