Jump to content
John Appel

Minimum pule width

Recommended Posts

I am using a G4 storm on my twin cylinder motorcycle engine. We have a throttle body on each cylinder and so we are using throttle position and revs for the axes on for fuel and ignition tables. Currently we are using a cam sensor and so we have one fuel pulse per engine cycle. On our fuel table we have a master value of 20 msec and at idle the no. in the fuel table is 14 so that the pulse width at idle is 20msec x 14% which is 2.8 msec. I want to try running the engine without the cam sensor and so I will have 2 fuel pulses per engine cycle ie. one pulse every engine turn. I then plan to halve the master value to 10msec to compensate. This means the pulse width will be down to 1.4 msec at idle.I may have to adjust the no. in the table to something a little greater than 14 to allow for the greater injector offset at short pulse widths. Do you think that the system will give good repeatability at 1.4 msec PW. What would you consider to be the minimum PW that would still give reliable operation. Regards, John

Share this post


Link to post
Share on other sites

You didnt mention if your 2.8mS is effective or actual PW.  I assume effective.  If so I would expect halving that will be fine. 

Note you dont need to change the master fuel number - the ecu takes care of that in its background calculation.  So, you can in theory switch between 1 engine cycle and 1/2 engine cycle injection rate without changing any other fuel settings.

Most modern injectors will start to get "non-linear" below about 1.5mS, but they are still usually quite repeatable until a good bit lower than that.   There are exceptions around though - for instance the old "Indy blues" were terrible at anything less than about 2ms, I suggest just try it and see.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...