VF Speedo Issue?

[dassaur]

mine is like that as the pointer sits just a crack under zero so my pointer is 2% fast and digital is 3% faster then actual

I've set mine to be bang on GPS speed.

 

[chrisp]

The ‘analog’ speedo is actually not analogue at all. It’s driven by a stepper motor, so it is quite accurate and very linear.

Check the start up ‘sweep of the gauges’ and see if it is all out by the same amount. All the gauges go through a minimum to maximum value sweep when starting the car (or rather ‘ignition on’).

It most likely that it is some sort of needle to stepper motor misalignment. However, several others have commented that the needle is firmly attached, so it is unlikely to slip.

The other thought is that an ‘end stop’ (at zero) may have broken. Sometimes these things are ‘calibrated’ by running the motor hard against a mechanical stop, and then calling that a reference point. So, if an ‘end stop’ has broken, the ‘start up sweep’ will be mis-calibrating the zero point as well.

 

[RevNev]

I've set mine to be bang on GPS speed.

Did you do that via the ECM with HP Tuners?

 

[07GTS]

I've set mine to be bang on GPS speed.

i thought about fixing the pointer on mine so it was on zero so same as digital and then adjusting with hpt but i always like a couple km fast up my sleeve, also a speedo reading spot on at 100kph can read under at 40kph, they are like MOI so faster u go the further out it gets

 

[07GTS]

Did you do that via the ECM with HP Tuners?

if u look at wheel speed on hpt it will be actual speed and the dash will be couple km faster so u can adjust the speed to make it closer, i havnt seen if it actually corrects the vehicle speed or just cluster speed yet tho

 

[dassaur]

Did you do that via the ECM with HP Tuners?

Yep. I found the easiest way was by adjusting the final drive ratio in the ECM (you can see it's 3.35:1). You could do it by changing tire specs and all that too.

 

[07GTS]

Yep. I found the easiest way was by adjusting the final drive ratio in the ECM (you can see it's 3.35:1). You could do it by changing tire specs and all that too.
View attachment 263059

thats strange as changing the diff ratio will also change the tailshaft rpm because ur auto that is taken into account, usually i just do the tyre revs per/km adjust by percentage and it corrects it all for speedo but dosnt affect the auto rpm

 

[dassaur]

thats strange as changing the diff ratio will also change the tailshaft rpm because ur auto that is taken into account, usually i just do the tyre revs per/km adjust by percentage and it corrects it all for speedo but dosnt affect the auto rpm

Yes changing the diff does change the tailshaft rpm and I needed to recalibrate the speedo since I went from 2.92 to 3.27. I put it to 3.27:1 initially, but then thought I could do better. Havent seen having the ECM at 3.35:1 have any affect at all on anything except speedo though?

 

[dassaur]

woops double post, ignore.

 

[07GTS]

thought u may have had to adjust the shift rpm or speed a little to suit the different diff to trans diff settings maby