Engine Model Spreadsheet

[jadeblaquiere]

A couple years ago I put together a spreadsheet to allow me to evaluate some potential engine modifications (e.g. what if I cranked the boost to 1.2 bar, how much power would I expect and what kind of airflow would I need). I cleaned it up a little and plugged in the basics parameters for some popular Porsche engines.

Of course it's only pseudo-scientific (I'm a software professional, not an automotive engineer), so don't hold me responsible for it being completely and totally wrong. There are some "empirically derived" fudge factors in there.

Model available at:

http://www.deblaquiere.net/engine-model.xls

I generally pay attention to the torque values. The HP assumes you're producing peak torque at the RPM value, which of course is probably not true as it doesn't take into account the effects of airflow (camshafts, cylinder heads, intakes).

I thought I would post this and maybe somebody will find it informative and useful, and maybe even fix all my mistakes!

If you do fix my mistakes, I'd like to hear about it. If you have questions, feel free to post or email.

--
Joe

[camgrinder]

Very detailed.
Thanks for not password protecting the file, I can see the formulas and that answers most of my questions. But give me a few days and Im sure I will have some for you.

[2.7RACER]

Joe,
This is one of those spreadsheets that I will be studying and learning from for a long time. Thanks for sharing.
Thermo-dynamics here I come.

[jadeblaquiere]

FYI : you might want to grab the latest version. It enables you to specify boost pressure before or after the intercooler. I also fixed an error where setting boost = 0 (normally aspirated) was represented as a very small amount of boost along with a pressure loss through the intercooler and a temperature change.