Lesson 02 : Ignition Timing Explained

Hello Andre & All,

I just have 1 question for this topic. On a mild modded engine, wouldn't it be best to complete a cam degreeing process and optimize/maximise the torque by closing/tightening the lobe separation angle, set the base ignition timing on the distributor then only fiddle the ignition maps in the EMS?

Thanks.

HH

Anyone?

Thanks.

Its always a good idea to degree the motor. But you cant set lobe separation and then tune and expect a certain outcome. I believe you should degree the motor and check the p2v and v2v clearances. Tune it and then play with the cam timing on the dyno to get the power band where you want it.

Theory is valuable and there are some great engine simulation programs available that will predict engine performance based on valve timing events (among others), however in reality if you've got access to a dyno then the simplest way to optimise the engine's performance is simply to make a cam timing change and see how it effects the torque curve.

When you're doing this it's always valuable to know where the cam centreline is before you start moving the cams though, and it's nice to know how much freedom you have before you risk mechanical carnage.

Every time you move the cam timing it will effect the VE of the engine and hence you will need to revisit both your fuel and ignition maps and optimise these to suit. As far as the distributor timing goes, if the distributor or cam sensor is run off a camshaft then you will need to recalibrate this any time you move the cam timing too.