Programmable ignition system

Some of you guys have become a bit peeved when I talk about using methanol fuel. Petrol has about a one third calorific value then methanol, so should produce more power in a Commando engine than methanol. I suggest the main reason is better is that it enables jetting to be closer to the optimum combustion conditions for maximum power without destroying the motor. Many years ago I had a conversation with Richard Bendell who started Motec and made the engine management systems which are used in Porsches and Ferraris. He said he did not sell a separate ignition system, and that I would need a throttle position sensor. I had considered buying a programmable Boyer ignition, however I could not think of an easy way to get an advance curve. I do not know what outputs are available on dynos, but with a lap top computer, it should not be too difficult to optimise the curve to give maximum torque at all revs, in relation to throttle position and programme the Boyer. At optimum combustion conditions, there is a balance between jetting, ignition advance and jetting. I found the following video interesting. I suggest that with petrol as fuel, the steps on the carburetor needles might be too large - changing ignition timing might give finer adjustment, and give better power output through more efficient combustion. -

I'm exhausted.

I did watch this to the end. It goes rather slowly and I think most of it would be known to anyone who has been classic racing in the past 25 years. Certainly those who are interested in what is behind engine performance.

For a more complete and structured analysis Chapter 4 Combustion in four stroke engines in Design and Simulation of Four Stroke Engines by Gordon Blair is very interesting.

Ignition type is controlled by the rules in most Classic race classes and therefore mapping an ignition system is only possible in a few more modern classes. I have observed well funded teams creating ignition maps using an engine brake dyno but this is pretty unusual. I beleive they map it to their injectors as well.

But this is pretty serious and expensive stuff.

Most of us are limited to inertia dynos selecting optimal ignition and carb settings from the hp/ torque curve. Guys I know do use Lambda Motec sensors for carb tuning and even these units can be very expensive.

You must also find a reliable dyno with a competent operator who isn't going to charge you thousands for the days of testing required. That is very difficult to achieve.