Quote:
Originally Posted by Mark JD  Hey Ronster....
GREAT answer! Info I always wondered about and you explained it very well.
Thanks!  |
thanks. it's what I do. been a gearhead for over 40 years and an engineer for almost 30.
to put a historical reference on that 11.3-to-1 figure, when I was building engines in the '70s my rule of thumb was 10.0-10.5 max using premium leaded gas (street use). that was cast iron heads and fixed valve timing with a wedge chamber. my experience with a hemispherical chamber was even lower compression with premium. hemis create a lot of power but they are very dirty by nature. the quickest way to increase the efficiency and (specific) power output of an internal combustion engine is to raise the CR. so 11.3:1 allowing 87 octane is simply incredible.
rg