to all of you engine experts,what is the formula for converting cubic inches to hp.i have a 01 SDV10 with 415 cubic inches. what would the hp be? thanks will add some more info, 3.73 gears. does anyone have same truck and know the rated h.p.?

 

There is no real formula for cubic inches to horsepower. My 330 ci ford (5.4 L) makes 300HP. My wifes 122 ci Subaru (2.0 L) makes 227HP. My old 351M (351 ci, 5.8 liter) only made about 130 HP!

Grim

 

There is no direct conversion from CI to HP. HP depends on a lot of different variables, even varying greatly in some applications from engine to engine, even when the two have the same CI. For example, one 351w might make 305HP, and the next 351 might make 500HP, and the next 351w might only make 185HP.

 

I beleive your truck is factory rated at 310 HP which would give you .75HP per cube if that helps.

 

What is the formula to figure the size of a bored engine? Like for example, if I bored a 302 .030 over what would the new cubic inches be? I think it would be a 306, but I don't know how to figure it.

 

93_snake;

You werent paying attention in math class. The formula for cylindrical volume is 3.1416 x (radius x radius) x height. That equates to 3.1416 x ((1/2 bore)x(1/2 bore)) x stroke x number of cylinders.

A quick internet search revealed a 4" bore and 3" stroke for the ford 302. Therefore stock displacement = 3.1416 x (2x2) x 3 x 8 which equals 301.593 cubic inches.

Bore the same engine +0.060" and you get 3.1416 x (2.03x2.03) x 3 x 8 which equals 310.709 cubic inches.

This is a difference of 9.116 cubic inches or roughly 3%. This would not yield a noticeable power improvement but the rebuilding of the engine would certainly make it feel more lively.

I hope this answers your question and remember, Math is the root of all. period. GlennMc.

 

I paid attention, but it was so long ago and I never use it now. Thanks for the info

 

Thats right, figures never lie but liars figure so Math is the root of all evil.

 

LOL