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Gear Shift Cut Period


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12 hours ago, VtrSp1 said:

Sorry it's a sequential gearbox with barrell position and load cell? Why  don't use the closed loop strategy?

its Close loop bro. Shift end mode is barrel position. 

I just changed to G4X and I think they change “max shift time” to “cut period”. So not sure what to put coz When I put 500ms value (copy value from Max shift time) , its delay power resume after gear finish changing. And help file still show Max shift time when I click at cut period.


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"Cut period" I think may have picked up the wrong label. it should be "max shift time", typically you would set this to quite a bit longer than your normal longest shift just as a fail safe.  ~500ms or so.

Yes it is normal for the shift to take longer in lower gears, this is because the ratio change (hence required rev drop) between lower gears is greater.

Your gear lever force trace looks a bit odd, not the usual "M" shape that I see, so there may be something not right there.  To optimise the shift, you need to log barrel voltage, gear lever force, RPM & cut at 500Hz, and zoom in to look really closely that the cut starts and ends in the ideal barrel position.  

If you attach an ECU log with these gear paremeters at 500Hz I will take a look.

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Yes the Cut period have a wrong label, it's max shift time.

@Adamw The Gear lever force look same  as my setup with G4X and log at 1000 Hz..

Only  in the G4+ with 100 Hz Log i have the M shape gear lever force...

The cut start at 30 Nm of gear lever force, a little before the barrell start moving so there isn't a really dog preload.

Probably with a dog preload the shape is a M style but a few test in the track the report from the driver is the lever feel smooth and  soft without the preload on the dog. Looking a log from the G4+ , i have the M shape without dog preload (the cut start before the barrell moving).

i compare a few log from same FWD car Quaife Gearbox with lever loadcell knob, about similar setup. Only with g4+ with 100 hz log i have the M shape.

another possibility is that the M shape is due to the lever mechanism system. In fact in the two examples I have shown the only difference is the gear lever. With the G4x I have the Quaife V1 lever while with the g4 + I have the quaife V2 lever

As about the upshift speed

On FWD car i see time from 95ms to 75 mS

On RWD car i see time lower to 60 mS on high gear


This is one of my setup w ith g4x..



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Dope, Thanks a lot @Adamw and @VtrSp1 , I have learn a lot about gear shift from your thread which is very helpful.

Yeah, I think gear lever force log are too low at 50Hz. Let me try with 500Hz.

Is there any possible to do Ignition trim during overrun downshift? Reason is during autoblip could make RPM up with less torque. 

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