VR 424 11p auto speedo correction ?

[Jaso74]

Hi all .

I've been searching but not sure on what way to go to correct the speedo on my VR 355 that I have just changed diff ratio from 3.08 to 3.77 .
I did find this - Q. How do I calculate a PPK change when I change my diff ratio?
A. See viewtopic.php?f=3&t=5670#p84421

But I can't find any PPK anywhere in tp5 software ?

I also seen mention of the jaycar correction unit but it seems the current one is no good and the previous version is no longer a thing .

Any tips guys ?

[Deuce]

It's definitely in there, I played with it for ages at one stage.
I'll look it up and report back.

[Deuce]

Hi all .

I've been searching but not sure on what way to go to correct the speedo on my VR 355 that I have just changed diff ratio from 3.08 to 3.77 .
I did find this - Q. How do I calculate a PPK change when I change my diff ratio?
A. See viewtopic.php?f=3&t=5670#p84421

But I can't find any PPK anywhere in tp5 software ?

I also seen mention of the jaycar correction unit but it seems the current one is no good and the previous version is no longer a thing .

Any tips guys ?

Powertrain
VSS
VSS - driveline ratio constant (engine code)
VSS - driveline ratio constant (trans code)

[delcowizzid]

They don't change the reading on the dash the ecu just passes through whatever speed signal comes into it

[Jaso74]

Thanks guys , I have ordered a Dakota digital speedo/tacho interface to put inline with speedo to correct it .
Seems to be the current best option .
For anyone else looking for a work around , this is the device - https://www.ebay.com.au/itm/324864700905 or https://www.dakotadigital.com/index.cfm ... rd1192.htm


Thanks .

[Jaso74]

So bit of a follow up question , If I splice the Dakota digital interface into the gear box tranducer before it goes into ecu/speedo, in theory I don't have to do any correction for diff ratio change in tp5 as the ecu and speedo will see the modified pulse ?
That's right isn't it or am I wrong ?

I have been too busy mucking for fueling tune issues etc and haven't got the speedo correction yet but the box is here ready to go .

[Jaso74]

https://forums.justcommodores.com.au/th ... v8.292274/

Found it .