Master spreadsheet for calcuating engine performance?
 

I have spent the last 2 hours rummaging through past posts by John, et al, trying to figure out the mathematics of calculating BALLPARK engine performance numbers from spec. It seems that torque/HP curves could be calculated by entering:

cam spec (lift, duration, overlap, etc. at 1mm)
bore
stroke
port size
valve size
static CR

It's just math (albeit somewhat complex math), right? Does anyone have a spreadsheet that I can punch these specs into and get a nice little virtual dyno graph? My end goal is to figure out what optimal port diameter is for a given cam and displacement.

Tell me if I am off base here.

There used to be a program called Desktop Dyno that was amazingly accurate IF you knew how to input all the necessary information properly.

Dunno if its still available but worth a look. :)

Thanks, Steve.

Their product, DynoSim, does what I want:

http://www.proracingsim.com/purchasejac2.htm

Not cheap at $100, but worth considering at that price. Their Dynomation product is a gearheads wet dream, but over the top for most hobbyists and kind of expensive for just being a toy.

Does anybody have anything free before I drop the coin? :)

Maybe play with this...

http://www.virtualengine2000.com/Calculator.htm

Aurel

You are quite welcome,..:)

I have both Desktop Dyno and Dynomation and both are excellent pieces of work for the price, respectively. It looks like DynoSim is a hybrid of the two and for the $$$, thats a bargain (IMHO, of course).

Like all engine simulation, these are only as accurate as the data that get entered but they can produce useful information for the purposes of comparison.

Tried it. Too simplistic.

Bosch Motorsport created Lapsim Toolbox to calc not only engine output, but vehicle dynamics simulation as well.....definitely not for the faint of heart

http://www.bosch-motorsport.com/content/downloads/Software/lapsimengine.pdf

Dynomation is a great piece of software. Equally good, but not as expensive (anymore that is), is Engine Analyzer Pro. I've used it for years and it's usually within 5% of actual output, if you enter EVERYTHING in properly. (it's usually low, which is a good thing). The best part of using such a program is to see differential effects of CR or cam changes. The actual number doesn't matter as much as the change it is reporting between different configurations.

Try Pipe Max by Larry Meaux it is about $50.00 and will give you everything you need to know to bring your project up to speed. It will give you specific design targets as well as the HP numbers.

regards

Pipe Max is a good program. Many top head porters are using it.

Hahaha...virtualengine2000 has a "Loan Repayments" calculator embedded in it!