VTC settings on RB25DET / z32 ECU

[vincentav8]

Hi,
Just curious about what people think are the best settings for VTC coming on (load) and then cutting off (rpm)
mine is currently set to come on at TP26 and cut off at 4900

is there any advantage / disadvantage of bringing this in sooner?

[R33 rb25det / s1 / z32maf&ecu / 550 inj]

thanks,
Andy

[Eric]

There's basically only one way to set it correctly and that's on a dyno/rolling-road.

You do one run with VTC turned off and one run with VTC switched on (permanently)
Then overlay the two readouts and the point were both graphs cross will be your ideal VTC switching point.

[fikemoo]

The factory settings are 1050 in and 4900 out thats what mine is set at and tp60

[Matt]

I found TP to be incorrect in the V2 RB25DET file (60 is way too high as you will see if you view the VCT outlay by rlight clicking on the fuel map, it should be 24 like with the Z32 ECU)

Attached is an updated version using the Z32 TP value for VCT

[fikemoo]

Ok great matt cheers for the v3 looking forward to using this on the car, are there any other changes to the map other than the vct settings???

Thanks Matt

[foliage]

There's basically only one way to set it correctly and that's on a dyno/rolling-road.

You do one run with VTC turned off and one run with VTC switched on (permanently)
Then overlay the two readouts and the point were both graphs cross will be your ideal VTC switching point.

There is one argument to this that with the different cam settings you should change the tune to suit, so basically you should optimise a tune with VCT off eg fuel + ignition to make the most power, then do the same with VCT on then overlay the graphs and set at those points THEN cut and paste the maps as well at those points.

The reason is with different cam settings you are going to be able to use more/less ignition timing. I'm guessing no one other than someone who tunes their own car would bother to do this, however it is the only way to get the ultimate result.