Applying Load

Applying Load

If you have access to a dynamometer, use it to apply load to the engine and increase the advance from a conservative value until peak torque is attained for every load and RPM point.

Note: Avoid sustaining an engine under high load and engine speeds for any length of time. It is good practice when tuning the high load bars to load the engine briefly before backing off and tuning the map while off load, then re-applying the load and comparing. Avoid holding the engine on high load whilst tuning to keep engine stress and heat to a minimum.

The process for tuning the load points and RPM ranges are very similar to Tuning for Fuel . Instead of aiming for good mixtures, however, you should be aiming for maximum torque for the given load and engine speed. You will achieve maximum power by aiming for maximum torque at all engine speeds.

As a guide, an engine will require less ignition timing with increasing load. It will also accept more ignition timing with increasing engine speed. If you are able to produce peak torque over a range of ignition timing, then always use the minimum amount of timing to achieve that peak torque. Quite often, there will be a reasonable margin between peak torque and detonation. If however, that margin is very narrow, or detonation occurs, then it is always advisable to trade off some torque for more safety margin.

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