Master Injection Time

I am tuning a single cylinder dirt bike, using an aftermarket ECU.

It would appear both Injection and Ignition are functions of TPS only, even though there is clearly MAP information available.

In any case, am curious about setting the master injection time. Does it matter the actual value?

For example it is currently set at 16 ms.

If 16 x 50% (injection table) = 8 ms

and 32 x 25% = 8 ms

End result is the same.

You are right, it is not usually too important. Two things to consider though:

1. If your "master" is too small you need very large numbers in your fuel table and there will be some maximum that it can accept. With Link ECU's for example the maximum fuel table number is 150%.

2. If your master is too big you will have very small numbers in your fuel table and this effectively gives you less resolution.

With Link ECU's, if using this fuel calculation method we generally say adjust your master fuel so that you end up with numbers around 50% in the middle of your fuel table.

Here's a video explaining the concept as applied on the Link ECU - https://www.hpacademy.com/previous-webinars/011-master-injector-pulsewidth-fuel-table-resolution/

Great answer. Thank you.