I recently discovered a very useful site from the minds behind Summit Racing Equipment, entitled On All Cylinders. Interestingly enough, I found them via their Pinterest board, where they had a number of great visual guides on spotting the differences between model years. Catch more of their guides on my newly-created board, Car Knowledge.
Anyways, the article that really caught my eye dealt with important automotive math equations. I envision having these scrawled on the walls in the ol’ dream garage. The whole article has some good points so make sure and give it a read. The equations in their raw form are below. Note a few of these are inverse, like tire diameter vs rear gear ratio, and of course horsepower vs torque.
Racing Carburetor CFM = RPM x Displacement ÷ 3456 x 1.1
Displacement = .7854 x Bore2 x Stroke x Number of Cylinders
Correct Compression Ratio (CCR) = FCR (Altitude/1,000) x .2
Tire Diameter = (MPH x Gear Ratio x 336) ÷ RPM
Gross Valve Lift = Camshaft Lobe Lift x Rocker Arm Ratio
Horsepower = (RPM x Torque) ÷ 5,252
Torque = (5,252 x HP) ÷ RPM
Rod Ratio = Rod Length ÷ Crank Stroke Length
Average Piston Speed = Crank Stroke x RPM ÷ 6
Rear Gear Ratio = (RPM at Finish Line x Tire Diameter) ÷ (MPH x 336)
CCs of Deck Clearance = Bore x Bore x 12.87 x Depth of Deck Clearance
CCs of Head Gasket = Bore x Bore x 12.87 x Thickness of Head Gasket
Compression Ratio = (Combined Chamber CCs + Gasket CCs + Deck CI CCs + (Displacement x (N)))/(Combine Chamber CCs + Gasket CCs + Deck CI CCs)
Where (N) = 2.0483 for 8-cylinder, (N) = 2.7311 for 6-cylinder, and (N)=4.0967 for 4-cylinder.