Originally posted by Just1MoreDave Two guys saw me take the shot and said I needed to take a shot of this one. "Dude, it's got a supercharger! Who puts a supercharger on a bike?" I'd tasted six beers by then with no lunch (see best tour by far, above) so I took the shot. Upon further review, I'm thinking it's a turbocharger, seems big too. Lag is worse with big ones, right? And I've seen race cars with glowing turbos, though I suppose Harley riders are used to some heat on the right knee.
Yes, that is a turbocharger, not a supercharger. Superchargers are usually belt or gear driven, and have positive displacement, and no lag. I have seen them on V-twins before, and wondered how much of a handful a machine that light would be with the extra added power. On top of that the Harley is not known for good handling, so the power would be useless for anything but straight line acceleration.
As for turbo lag being "worse" for bigger ones, well, I suppose that it would be relative. A turbo sized way too big on a small displacement engine may be largely ineffective, as they only turn in response to the air exiting the engine. There has to be a tipping point where the balance between the volume of air coming out of the exhaust becomes more or less useful in spinning the impeller to draw the intake charge into the airstream and compress it. Too small and it doesn't really make that much more power, too big and the hot gasses turning it just blow right by.
It looks like there is a heat shield on the elbow coming out of the hot side of the turbo, so I imagine the rider doesn't have to be too concerned about scorching his knee, provided he isn't riding with shorts on.