cossie brad

I got a XR4i with a V6 BOA fitted and I just swapped from a type 9 box to a MT75 with a electronic speedo drive, obviously the 4i has no wiring there for this so I was wondering if anyone on here knows how to wire up the speedo drive to the ecu and clocks?

stevieturbo

adapting an electronic only box to drive a cable only speedo isnt easy or cheap.

basically it'll need something like this ( and I have one to sell lol )

http://www.abbott-tach.com/cablex.htm

Best long term is find a box with a cable take off instead

doga-ot

iTrader: (1)

I have a saph with boa on mt75 hybrid use speedo cable for the speedo and green wire from edis for rev counter

Marc sierra

iTrader: (1)

All 2wd MT75 boxes are prepared to have the cable speedo drive installed. You just need to knock the bung out of the box that is on the opposite side than the electronic sensor. Then you fit an oil seal to the hole and use a different speedo cog, a longer one that sticks through the oil seal and you have a working speedo drive.

cossie brad

Thanks guys, what I was planning on doing was using the guts from a electronic speedo from a granada mk3 and fit them into the sierra clocks but I need to know what pins do what on the box and which pin it goes back to on the ecu and what wire to connect to on the clocks.

Marc sierra

iTrader: (1)

Why do you want to use the Granada speedo? It's easier to convert the gearbox and use a sierra speedo. Plus the sierra speedo is more reliable and also more accurate I think.

cossie brad

Just thought it would be easier to wire up a electronic speedo than to try and find the right speedo drive and seal for the gearbox, I wouldn't have a clue where to get them from? I'm guessing the dealer won't have them as our local dealer doesn't have anything for a Sierra anymore!

Marc sierra

iTrader: (1)

I got them from my dealer a fews years back. If you know the finis code they should be able to order it easily. Which cog you need depends on what diff you are using (and tyre size). Easiest is to get the cog and worm wheel from a dohc MT75 box.

Btw, how the cog and worm wheel should be changed is in my 24v project thread somewhere.

cossie brad

Thanks Marc I'll try our main dealer to see if they can still get them, did you have the oil seal from the dealer too? I'm using a lsd from a 2.9 4x4 estate with 205/40/17 wheels the gearbox is from a 2.5td with a 2.9 4x4 bellhousing fitted to it.

Marc sierra

iTrader: (1)

Yes, I also got the oil seal from the dealer. With those tyres and that diff (should be a 3.62) you can use the worm wheel from a DOHC MT75 together with a 23 teeth cog (blue cog if I remember correctly). As standard the DOHC has a white/yellow 22 teeth cog fitted, but I found the speedo overreads as standard and the 23 teeth cog made it perfectly when I still had a 3.64 diff.