car-calc

I'm now working in conjunction with Race Engine Technology magazine. The remit is to build a engine as it would have been in 1976, using off the shelf parts, a set of feeler gauges and a dial gauge and the engine will rev to 12,000 rpm and produce 170bhp.

Car-calc is a microsoft excel workbook that works out in seconds common engine calculations and allows you to keep everything in one place, I first wrote this program on a Sinclair Spectrum in 1981 for my local college.

You may already have something to work out most of the calculations to build a engine, but this programme includes something that nobody has, and that is about working out how many revs an engine will reach before it has to start sucking in air (this is very contentious)

The first part in the program is to work out rpm, diff ratio, gear ratio, tyre and wheel size = MPH or KPH. This is useful when you are trying to maximise the engine revs to mph.

At the bottom is a separate sheet with all the tyre sizes, you want to copy Rolling Circumference and paste it into the box.

Work cubic capacity and a compression ratio predictor without having the combustion chamber size.

Work out what rpm your engine can rev to before it has to start sucking air in

I also did a experiment to retard the inlet timing by 1 tooth, in doing this it also retarded the exhaust timing as well as its a single cam, i also had the back of the exhaust tappet setting by 30 thou, making the exhaust about 20% less efficient. See results in the program