Not Ranked
Mike,
I think you may have hit upon it! Cylinder pressure must be it. It seems so obvious now that you have said it. The funny cars on their nitro-methane must be producing cylinder pressures that go off the charts and that is why they knock the breath out of you when you stand at the starting line. Ken made the comment about lowering the compression on the Chevy BB and the punch in the sound went away. Again, directly related to cylinder pressure. The old 427 engines have high compression by todays standards, so they have that punch as well. A long rod-to-stroke ratio will park the piston at TDC longer and get that higher pressure peak. The stroke is shorter on the 427, so its rod-to-stroke ratio must be higher than the 428. Anybody know if the connecting rod on a 427 is longer than the rod on a 428? That would make it even more pronounced. I'll check my books when I get home. Of course this would mean that the 427 is not unique in its ability to produce this effect, but it may be well suited by virtue of its bore-to-stroke ratio.
Charlie
(still waiting for someone to donate the 427 to start the comparison studies . . . in the name of science, of course).
|