[83fox]

no questions, just some information i thought would be helpful to others since horsepower and torque numbers are frequently asked.

FINDING HORSEPOWER FROM THE 1320

Horsepower=weight x 0.4 x 1/4 mile MPH
-------------------------------
282


CALCULATING HORSEPOWER AND TORQUE

Horsepower=RPM x Torque
---------------
5,252 RPM

Torque=5,252 RPM x Horsepower
--------------------------
RPM

FINDING THE RIGHT CARBURATOR FOR YOUR APPLICATION

Most street driven motors have a volumetric effeciency (aka VE) of 75% to 80% and more performance goals have a VE of 80-95%. VE can be tested on a dyno.

this is to help choose the most efficient carb for your set up

VE x cubic inches x Max RPMs
--------------------------------- = cfm
3456


CUBIC CENTIMETERS TO CUBIC INCHES

cc/16.4=ci

COMPRESSED HEAD GASKET VOLUME

B=Bore

B x B x Gasket Thickness x 0.7854=Compressed Head Gasket Volume

PISTON/DECK HEIGHT VOLUME

Bring a piston to TDC and use a dial indicator to measure the distance from the top of the piston to the deck of the block, its usually between .008 to .025, unless the deck was shaved down.

The measurement you got is going to be represented by the letter D in the following formula:

B x B x D x 0.7854=Piston/Deck Height Volume

PISTON DOME/DISH VOLUME AND COMPRESSION RATIO


First things first, measure the volume of your pistons, even flat top pistons with valve reliefs. You can do this by either using a graduated cylinder or by contacting the company that makes the pistons. Then covert the cc's of volume of the piston into ci's with the formula above.

Here comes the fun part, the compression ratio

V=Cylinder Volume
C=Combustion Chamber Volume
G=Compressed Head Gasket Volume
P=Piston Dome Volume
D=Piston/Deck Height Volume


V+D+G+C+P
---------------
D+G+C+P

just plug in your actual numbers and divide the sum of the top number by the sum of the bottom number and that will give you your true compression ratio

[ujslost]

Good Info right there.

I say this should be a sticky.

[tmoss]

if you go the download section of my website you can pick up an Excel file called "helpful calculations" that has a BUNCH of stuff in it..................

[Squints]

don't forget HP estimates based on boost.

(Boost pressure/14.7 + 1) x (N/A Horsepower) = Boosted Power

example: (8 PSI / 14.7 + 1) x (245 BHP) = 378.333

this is based on air pressure at sea level and does not take into account parasitic loss.

[83fox]

^oh yeah i forgot completely about that


anyone else have some math they want to add to this thread?

[Modified88Dreamer]

Originally Posted by 83fox ^oh yeah i forgot completely about that anyone else have some math they want to add to this thread?

I've never been good at it, so you can count me out