Originally Posted by
wmazz
Why can't I just make the most power possible and gear it right? Tune it to be the most controllable,
drivable combination possible, without detuning the engine.
I know I am not the first Dumb mule to want to this but can you tell me why this didn't work?
I have done it before, In motorcycle speedway racing. I took an overpowered European long track
engine, and found a solution that made it so drivable and trackable on the short tracks in the USA.
The bike got great traction, and even with worn out tires.
First of all this is why:
Originally Posted by
wmazz
I have a SH 15
A SH engine is not the best engine to "play" with without real modifications. The engine is limited by timings and other dimensions....
Again: when changing the head clearance you do change the ignition timing which does have an effect on the powerband and max rpm. With spark ignition changing the head clearance the spark will always be on time.
A tight piston will end up in a better performing engine but if it is to tight it will stay with a pinch for a long time giving some resistance reaching top rpm. Some brands like Sirio has a kind of diamond shape piston (the side above the oil rings is tapered and the side under the oil rings is tapered), the side is not realy straight, the corner on the side is on the oil rings and touching the sleeve will get a flat spot taking care of the sealing building up compression. The wider the flat spot the better the sealing and longlivety of the piston.