View Single Post
Old 10-18-2004, 03:16 PM   #9
Scooby Guru
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
2003 GGA MBP
12.9 / 105+


well, along those lines... it is essentially the same question as to why it is "bad" to "lug" the engine in a too-tall gear at too low of an RPM.

and the answer to that question has been, in my experience, that it puts a LOT of cylinder pressure in the chamber.

now, why does that occur? i think it has to do with the speed of the receeding piston during the power stroke. if the cylinder pressure peaks quickly and the piston does not have time to absorb that pressure and convert it to downward movement, then very little of that pressure will be used to perform actual work. instead it will be dissipated in the piston/rods/bearings/headgasket/rings, etc.

in other words, it's a matter of matching the rate of chamber volume expansion due to downward piston movement to the rate of the combustion event.

* Registered users of the site do not see these ads.
ride5000 is offline   Reply With Quote