Thread: diff ratio change

Originally Posted by shack

No no, the speed correction device is ONLY for the Speedo on the dash, it does not transmit any data to the engine ecu, the engine ecu is what takes care of the cruise control and it has a number of maps and other settings that allow you to program the correct "expected speeds for given rpm" if you like. These are what needs adjusting if you change diff gearing, or transfer case ratios, and only on a manual. As stated the auto has the ability programmed in to be at numerous ratios during driving because of the torque converter.

Pm me if you want more info..

Cheers
James

Is the engine ECU a straight forward Nanocom job at home or is that getting into the deep dark bowels of the ECU?

You would have to do it with td5map editor or tuner pro I assume

Originally Posted by Slunnie

Is the engine ECU a straight forward Nanocom job at home or is that getting into the deep dark bowels of the ECU?

Originally Posted by Slunnie

Is the engine ECU a straight forward Nanocom job at home or is that getting into the deep dark bowels of the ECU?

Not a nano job sorry..

Edit: what I mean by that is that the Nanocom can't make the adjustments, but it can upload the edited ecu file.

I'm running 265/75 16 on my auto d2 with 4.11 diffs.

Every thing works as it should. The only thing was the speedo was reading slow, which I fixed with a speedo corrector.

I did fit tyres first though, and then the speedo correcter. The diffs were changed at a later time.

Originally Posted by d2dave

I'm running 265/75 16 on my auto d2 with 4.11 diffs.

Every thing works as it should. The only thing was the speedo was reading slow, which I fixed with a speedo corrector.

I did fit tyres first though, and then the speedo correcter. The diffs were changed at a later time.

How behaves the D2 with the 265/75 and 4.11 Diffs? Sounds pretty short to me?
Which revs do you have at 100km/h? And how changed fuel consumption?
I am also on 265/75 with good Mapping and so on but sometimes it feels a little bit tired...


And for topic: have also a Hunter device installed since some years. It makes what it should. Speedo sits spot on and CC and everything else works as it should.

Yeah I have done mine too for my D2 manual, running 4.12s and 33s it's really good

Originally Posted by Werdenfelser

How behaves the D2 with the 265/75 and 4.11 Diffs? Sounds pretty short to me?
Which revs do you have at 100km/h? And how changed fuel consumption?
I am also on 265/75 with good Mapping and so on but sometimes it feels a little bit tired...


And for topic: have also a Hunter device installed since some years. It makes what it should. Speedo sits spot on and CC and everything else works as it should.

Speedo Corrector Module | Jaycar Electronics

Have been looking for a corrector and as this is the most recent post regarding it, just adding to it post my research

Firstly has anyone used one of these??

As far I understand from the blurb, this is mounted / wired into the speedo line, post the ecu. The detection of the pulse signal would if I surmise correctly be only one a couple of different standard ones between the multitude of cars which include Land Rover????

The changing of the ratio could not be easier in an analogue sort of way with two rotary switches to turn, one for 10's and one for 1's. As my display is out at the moment getting new bright led's would be interested if it was that easy to do...


AA0376-manualMain.pdf

Originally Posted by Slunnie

The SLABS generates and sends a speed signal that is taken from the 4 ABS sensors. When you change the diff ratio, the driveline speed stops matching what it expects to see at the axle because of the diff change. If you use a speedo correction unit on the speed output signal at the SLABS computer it will correct this. BUT when you are doing this, you're not correcting the speed of the car, you are correcting what it should see because of the diff ratio change - this is important. So, to gain cruise control back again, correct from 3.54 diffs to 4.12 diffs. If you're running 285/75-16 (33's) then your speedo will be accurate. To do this you will need to use a pretty specific speedo correction device that needs to pass through the baseline diagnostic frequency, which most do not do. See this article I wrote about 17 years ago for fitting and a SCU that works.

Truspeed speedo correction installation - www.slunnie.com

Slunnie you did a great job on the write up by the way. Been thinking, always a troublesome thing to do as am now wide awake at 4.20....

Not so much in regard of the Cruise control as have an auto but probably more importantly, HDC and if I was to use it. Heard many a comment re the HDC is just a bit too fast for steep steep tracks and if using the larger diameter wheels, this only makes the issue worse, it thinks its doing 7 but factor in the correction and its faster again due to the increased diameter of the tyre per each reporting ABS strobe.

The next bit based on the blurb from Jaycar

Speedo Corrector Module | Jaycar Electronics

https://www.jaycar.com.au › speedo-corrector-module








This module alters the speedometer signal up or down from 0% to 99% of the original signal


IF and it is a big IF at the moment that the Jaycar MK11 speedo correction works and it was put forward of the SLABS not post as per your instruction set, the simplification of the control setting - open it up and spin the control- could work in actually sloooowwwwinnnngggg down the HDC to more than half if desired... or setting it up with a dial on the dash to control the speed module in real time (now I am getting ahead of myself.)