FINA4

Do you experience more engine vibration with our supercharged engine than your non-supercharged engines?

Sandy S

No. The engine is smooth as a V6 but has the low end torque of a V8 (just not the sound). Also there is no turbo lag at all (since there is no turbo)

terminal nonchalance

I don't think it is the supercharger...v6's are not a naturally balanced engine like a v8. Smoothness is not a virtue in this engine design and balance shafts are a v6's friend. Many have noted the slight vibe at idle many theories as to why it's there, but nothing to worry about. This motor is a beast and pretty high strung for the size, it is the feeling of power ;-)

FINA4

I had 3.2 FSI V6 in my B7 A4 Avant and it vibrated much less. And I don't mean at idle, but above 3krpm or so.

Excelsior7

I think it's possible that not 100% of the Superchargers that Eaton makes for the S4 have their vanes perfectly balanced. Superchargers spin very, very fast, and even a tiny imbalance would cause a noticeable vibration.

Also, what do you mean that a V6 isn't as naturally balanced as a V8? I wouldn't think that removing two cylinders would alter the balance, if one came off each side, but I'm wrong quite a bit.

IAS5

engine smoothness has to do with the angles of the cylinder banks, and the forces/counterforces of the pistons, as well as the number of cylinders.

there was an excellent article in C&D a month or two ago explaining this.

terminal nonchalance

I am not a mechanical engineer, but there are some good articles on the web that explain it much better than I can. I would search fro the C&D article referenced above that was a good one.

From my experience and from what I have read, a V6 is a nasty engine to tame especially if you go for extreme V- angles. V6's almost always utilize balance shafts to smooth out the vibes and give an artificial feeling of smoothness.

Mike

FINA4

And for me, the hotter the engine, the more obvious the vibration.

FINA4

Also, for me the vibration is then transfered to clutch and shifter via transmission.

Excelsior7

I can definitely see if there is a different bank angle, and probably that less mass offers less dampening of the system.