Originally Posted by muckz

Well, Diesel gets its name from its inventor, Rudolf Diesel. Miller gets its name from its inventor, Ralph Millerf, who patented the technology in the 1940s. The regular engines are actually Otto-cycle engines because they were invented by Nikolaus Otto.

A Miller-cycle engine uses a supercharger, but it also leaves the intake valve open during part of the compression stroke, so that the engine is compressing against the pressure of the supercharger rather than the pressure of the cylinder walls. The piston does less work because part of the work is done by the supercharger. The piston compresses about 70 to 80% of its total movement upward in the compression stroke, and the other 20 to 30% are essentially "free ride" with no energy loss. This cycle works only if the supercharger can compress the air in the cylinder at less energy than the piston. Hence, it has increased efficiency.

Originally Posted by NBred94

It was my understanding that modern ECM's are sophisticated enough to pull the timing if detonation is detected so you can run the lower octane fuel without hurting the engine.

I'm pretty sure that's what my wife's Infiniti G35 does. The owners manual states that you can run 87 octane fuel, but to get "optimum performance" you need 92 or higher.

Originally Posted by bossco

yes, but I beleive it was a miller cycle engine IIRC??