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      04-23-2011, 11:02 AM   #101
skier219
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Quote:
Originally Posted by simianspeedster View Post
What are they doing to address smoothness? I imagine they're using fluid-filled motor mounts or whatever the latest traend is there, but what else can they really do to make a 4 cylinder not feel like 4 cylinder? Especially in comparison to one of the smootest engines available, the belovd N52.
The best option would be balance shafts, but they do bring tradeoffs including friction and weight, and their effectiveness really depends on other specs (bore vs stroke, etc).

It's not impossible to have a sweet 4 cylinder -- the engine in my S2000 is an example. But once you start using forced induction and other tricks to really increase the effective displacement, the engines can turn into beasts that make all sorts of rude noises and vibrations. The turbo 4 in our Acura RDX is an example. Half the time it sounds like an air conditioner pump. Many buyers like the turbo whooshes and seem to think its a great high tech engine, but that particular vehicle would have been way better with a V6. I don't see any benefit to the turbo 4, not even fuel economy. Wringing the life out of a four to make it work in a heavy vehicle usually doesn't fly in my book.

Oddly, the best combo I've owned was a Subaru Outback XT in 2005. Though the H4 is known to be rumbly (as many flat 4 and 6 motors are) it has perfect balance (like the straight 6) and was awesome with a turbo. I still wouldn't pay $55k for that kind of engine in a Z4 though.

Last edited by skier219; 04-23-2011 at 11:07 AM..
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