[TELVM]

Originally Posted by Geebee

The data and anaylis in the second pdf don't seem to agree.
Look at the HP rating through out the range and the non grooved head is almost always higher sometimes dramatically.

Please notice the graphs in the second pdf aren't horsepower curves, but in-cylinder peak pressure curves.

Less peak pressure at the right moment of piston travel can make more torque than higher peak pressure at the wrong moment of piston travel.

The testing was also flawed because the data on combustion chamber size is smaller for the grooved head.

Two cylinder heads were used. The highest difference in combustion chamber volume is 3.3%. No two cylinder heads of same type are identical due to casting and machining tolerances, see that the intake runners had larger volume in the non-grooved head. I don't think that's enough to discard the experiment as dramatically flawed, but that's just my opinion.

He could have used just one and the same cylinder head, first without grooves, then grooved. But he didn't.