Quote:
Originally Posted by mr220v
Atkins cycle refers to a motor with a power stroke longer than it's intake stroke. Originally this was accomplished with weird crankshaft/engine designs, but can also be accomplished with offset cams and cam timing, which is what this motor does.
Offset cams are often used in race engines (or by cheap 4age modders who only want to buy an intake cam). But again, the object there is to increase intake and exhaust cam overlap (better efficiency at higher rpms), not to delay closing of the intake valve to actually waste a significant portion of the compression stroke. That would be counterproductive in a race engine.
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Again you're sorely mistaken. Overlap is for exhaust scavenging, late valve closure is for maximizing volumetric efficiency due to acoustic intake effects. The inertia of the column of air traveling down the intake provides very significant pressure at the peak of the "wave".
Some engines have nominal 300 degree cams. Do you really think these cams close right after BDC? Hint, they close LATER than a 1NZ-FXE.
This is why I'm getting my 1ZZ-FE intake cam reground for higher duration: Improved efficiency AND improved peak power.