Engine equations web page

[onearmedbandit]

Following on from the thread regarding exhaust design, which touched on VE I did a web search and came across this page that has many equations relating to VE, working out displacement,estimating HP, etc. Probably useless to many, but could be of interest to some.

AJ Design (http://www.ajdesigner.com/phpengine/engine_equations_volumetric_efficiency.php)

Click on the link to the left as well.

(Years ago I read that HP=torque*rpm/5252 (ie at 5252 rpm HP=torque) and a few have doubted me on it, saying 'ah all engines are different, etc'. Well seems I read correctly.)

[John]

edit: thanks for the link good formulas there... i screwd up :Punk:

[TwoSeven]

The VE formula there is a bit basic but pretty good. I've been working on one for a while, still have some more bits to put in it tho. Usually they dont take into account cylinder head design, so i've found measuring the volume with a syringe and water after the piston is at TDC to be most accurate. I also like the idea of taking into account the affect of sticky fuel - but dont have a flow meter - so that will have to wait.

People get confused between BHP and HP quite often. Basically, HP is no longer used (hasn't been for over 20 years). Use bhp or ps. Although if you want to work with VE you'll probably be using watts.

I've found it ideal to try and calculate power at the crank when working on engine formula, and at the rear wheel when working on final drive - there is usually a few percentage points difference.

[Ixion]

Bookmarked. Thanks