R&D thinking

[GearHead_467]

Anyone every touched base on the theory of increasing the combustion process past 30 degrees past TDC. In theory if it could be done the process would produce a measureable amount of horsepower with not alot of modification, instead of the a/f mix burning until 30 degrees after tdc and then using momentum to finish out the stroke the increased burn could push the piston down to about 10 degrees before bdc, in turn causing a slightly higher rpm range as well as horsepower gain, but Im just thinking outside of the box, let me know what you guys think.

[MagicRat]

The hot gases continue to expand and produce power after the actual 'burn' has been completed.
So what you suggest, while increasing power would dramatically reduce efficiency.
I think you could get the same power benefit by using lower compression and a whacking big supercharger to really fill the combustion chamber with fuel/air mixture, as is done in top fuel drag racing. So much fuel/air is stuffed in those engines they do not fully burn all the fuel on the power stroke, hence the flames out the exhaust at open throttle.

[UncleBob]

not to mention the exhaust valve should be opening before 10* BBDC even on a low revving engine

[curtis73]

Plus there is also already a significant amount of unburned HC in the exhaust. I would think extending the burn would make that worse.