some engine math.. need help

gixXxinRS
09-17-2003, 01:00 AM
i have got a few questions about engine geo. that maybe some of you can help me with..

what effect does head cc Vs. Cyl cc have on a motor

a stock LT1 has a 58cc head and a 717.29cc per cylinder.
which is:
58 / 717.29 = 0.080862158

now a 383 (784.9cc per cylinder) with a 64cc head is:
64 / 784.90 = 0.081541127

assume the CR (say 10.5) stays the same which would be more efficient..

or can this not be loked as so simply as this..

i know the Bore/Stroke has an effect..
anyway thanks

SStrokerAce
09-17-2003, 06:20 AM
The compression will change in your example.

That's what you are looking at CR.

Other than you have to add in dish/dome volume on the piston and the distance between the head and the top of the piston at TDC and you are pretty close to the CR equation.

Revearse the numbers around in your formula.

Total Volume(cylinder and chamber)/Chamber Volume = CR

717.29+58/58 = 13.36:1

It would be more like 75cc with the piston valve reliefs and the gasket, so you would then have:

717.29+75/75 =10.56:1

You might want to check that 717.29, a stock 350 has 43.73 cubes per cylinder.

Bret

TreySpeed
09-17-2003, 10:21 PM
heads are cubic centimeters
Displacement is cubic inches
:p



who was the brains behind this?