Exhaust Gas Analysis - Ignition Timing

I see this more often than I want. Mosty when a customer comes in with the latest and greates cams that are poorly matched to their engine combination. More is not better. More cam duration requires more static compression, or dynamic compression drops. A less efficient and lazy engine is the result. Even if peak power increases, the engine takes longer to rev to the same engine speed, resulting in a slower combination.

Choose to keep the cam(s) and increase compression, or change cam(s). Higher octane fuel doesn't help. You might try running a fuel with faster burn characteristics and working with cam timing as a band-aid fix to poor cam selection. But it is not the best answer.

O2 and CO2 levels will tell you a good bit about ignition advance - especially when more is needed or the fuel is way off. No specific numbers, as each engine combination and mapping alter combustion efficiency. But the ratio of both gases can indicate a lot until you get a good grasp on a particular engine combination.

THC goes up with poor combustion, as does carbon particulates (soot).
Fuels with too slow burn rate for needs, as well as poor vaporization, atomization and homoginization, will all require richer fuel mixtures - increasing CO% required for best output. But you can go too far with all of these as well. Great BSFC and response, but limited output due to fuel vapor displacing air.

NOx will provide a lot of info on ignition advance limitations and knock limits prior to the onset of detonation in knock-limited combinations.

I have putting together more information on gas analysis over the past few months, but it will take a few months to get back to it. We are in the middle of moving into a new facility. I will post up when it is complete.
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"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss