Jump to content

Zf shift torque reduction settings


Recommended Posts

What are the options available for selection for auf11992 - type of cyl cut during zf gear change 0, const number, 1, even number... And what is the differences between them? 

 

From what I can see, earlier FG xr6t have a value of 1 and the XR6 sprint has a value of 3, but there's no description for this scalar

Link to comment
Share on other sites

Hi Richard,  there is basically two methods for fuel cut that the  PCM checks against.

  1. If the value of auf11992 is 0 or 2 it will do the cut for all injectors (cylinders).
  2. For all other values it only cuts to an even number of cylinders depending on the torque reduction required.

The workshop version has a table that can be used to control this (auF12783):

image.thumb.png.02e011355c75ad96c3793193b70406c6.png

This basically controls the number of cylinders to cut depending on the number of injectors the PCM calculates it wants to cut. If you use the second option above then you could change this table and have it cut another number of cylinders.

Link to comment
Share on other sites

On the topic of zf shifting, how does one achieve this type of shifting where it looks like fuel is not cut and only ignition is cut, or can you get a 100% ignition cut without fuel cut on shifts? Video to explain or show what I mean. Under normal driving in manual mode, I can see ignition timing dips to -25 deg but under hard throttle, ignition cut doesn't seem to be as much cut

 

 

Link to comment
Share on other sites

Most flames are due to the injector slopes and offsets being wrong. This means during a fuel cut they don't completely shut off or it is relying on heavy LTFT corrections, then when it goes into open loop (eg wot) the commanded lambda is totally wrong at low loads (eg decel or shifts) 

The pcm has an external ignition driver which has the current engine crank angle sent to it. So there is no easy way to implement an ignition cut. A proper ignition cut is very loud and destroys mufflers and cats. You can't run it on the street easily. 

Have a read over the traction control and the torque reduction and there is a setting that explains when it stops trying to use spark retard. The minimum torque ratio is the one you want to look at. 

Link to comment
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.

 Share

×
×
  • Create New...