Ignition and Fuelling

[Stretch]

Guys

Does anyone have any views when changing the ignition in relation to the fuelling.

Otherwards, if I have a 2nd map which has 8 degrees more in certain places then should I richen the fuel cells in those places.

I assume you need more fuel when using more spark so I was wondering if there was a method in calculating the fuel numbers etc

This is for a K8 GSXR-1000 using a M800

Cheers

[stevieturbo]

Tune it on a dyno.

Why would you have such a huge variation between maps ? 8deg is pretty massive.

[Holmz]

... so I was wondering if there was a method in calculating the fuel numbers etc

The combustion is a function of chamber pressure and spark advance, so it is possible to have some areas where the voumnetric efficiency is low (and hence chamber pressure is low) where one could run more advance. As the chamber pressure gets higher, then often detonation can start happening.

Ideally we would probably be running fuel with infinite octane, or combustion speeds that require less advance (but combustion speeds greater than the speed of sound equates to detonation), or some direct injection, or some variable compression ration to get constant chamber pressure.

Tune it on a dyno.
...

^There^

There is the issue of the 8 degrees and the richness...

If one is tuning solely for max power then it is easy.
If tuning solely for max efficiency, that is also easy.
If tuning solely for emissions, that is also easy.
(One could also talk about engine longevity)

But when you start to talk about combinations of the above, then it gets complicated to work out the optimum.

If you have a race bike which also needs some eye on fuel consumption, then you will need some dyno time.
You will be looking at torque, lambda, knock, EGT, consumption, and possibly gasses.
The first 2 or 3 may be all you need; or all you want.