Quote:
Originally Posted by Grape Ape
The difference is that the high revving motor would be smaller and lighter. For instance the M3’s new V8 gets a naturally aspirated 420hp out of 4.0 liters (~250 cubic inches). They claim it is one of the lightest V8s ever (at 445 lb) even though it has DOHC & 4 valves heads.
The lower inertia of the smaller moving parts means that the engine can change speeds faster which allows for quicker shifts. This would also let you accelerate faster in gear, but I don't know that the effect would be measurable.
The smaller bore and stroke means less friction which should allow for better mileage.
I suspect that a higher red line should also make it easier to find an efficient RPM to cruise at on the highway.
The big downside that no one has mentioned is the price.
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The M3 V8 is part of the reason why I started this thread. It makes slightly less power than the LS3 and weighs slightly more -I think, its hard to get the weight of the LS3. But in both cases they are within a few percent. So, I'm trying to figure out what advantages there are to the approach that BMW took. The european tax on displacement might have something to do with it, but I doubt that would stop many from buying a car in the price range of a BMW. Lots of people over here don't care about a gas guzzler tax on the cars like the SRT8's and they don't cost nearly as much as an M3 would, even over there.
Maybe its because a BMW buyer prefers a high tech, high specific output for their engine? Factors like that are part of the process when buying such a car. And there is the exhaust note too. But these aren't performance related, they are personal preferances.