UK Dials and Speed Converters

[Mike_Mac]

Just a quick question...

Does fitting a UK speedo unit remove the need for a speedo converter? I'm assuming that that's where the speed signal is coverted to either km or miles per hour depending on how the speedo unit processes it.

If so then I can remove all the A/M wiring I've had to do to mine and restore it to a stock loom (much preferred).

[Martin F]

I believe the conversion is done in the odometer.

[Mike_Mac]

Originally Posted by Martin F

I believe the conversion is done in the odometer.

No - the original #1 speed signal from the gearbox splits - with one feed going to the Odo and the other to the speedo. The retransmitted speed signal from the Odo is sent to the ECU, not the speedo.

I'm pretty positive the signal is interpreted differently by J-Spec vs UK speedo units, but just want to make sure that UK speedo dials will match my J-Spec loom connector block's wiring.

[Martin F]

Yep, you are of course correct.

It was this buffering of the signal onto the ECU I was thinking about.

Originally Posted by Mike_Mac

The retransmitted speed signal from the Odo is sent to the ECU, not the speedo.

I'm not sure whether the speedometer can be changed to read in MPH easily but here are the instructions for converting the odometer.

http://homepage.ntlworld.com/peter.b...s/odometer.htm

Some more info which may come in handy for others (courtesy of Pete Betts)

http://homepage.ntlworld.com/peter.b...ips/speedo.htm

[Mike_Mac]

Originally Posted by Martin F

I'm not sure whether the speedometer can be changed to read in MPH easily but here are the instructions for converting the odometer.

http://homepage.ntlworld.com/peter.b...s/odometer.htm

Some more info which may come in handy for others (courtesy of Pete Betts)

http://homepage.ntlworld.com/peter.b...ips/speedo.htm

That's the instructions I was going to use to do mine. They're definitely a useful guide and quite easily done. However the guy I got my speedo convertor from can do that as well as adjusting the odo to display the correct total in miles, so I thought I'd let him do the work.

I'm 99% positive that the way the speedo itself interprets the signal dictates whether the reading is km or miles - it's the only place along the path that has any signifcant architecture. My only concern is if the UK speedo would interface with a J-Spec loom. Hopefully I'll be buying Mo's UK dials, so I can do a direct comparison.

[Mike_Mac]

Well I've just swapped the speedos over (steady on Kev ) and all seems fine. Although I will need to check it by GPS the UK speedo appears to be reading ~33% less than the Jap one, so once it's confirmed I can strip out all the aftermarket conversion wiring and return it all to stock.

[The Restorer]

Glad it's worked for you.

[Mike_Mac]

Originally Posted by The Restorer

Glad it's worked for you.

So am I . The rear fog symbol served its purpose too, so as soon as I get my adjusted odo back I can stick my interior together at last!

[Kev.O]

Good news Mike

[Mike_Mac]

Well I've had it out briefly to test the speedo against a satnav (suspension is truly f*****) and the speedo is reading more accurately than the converted J-Spec one. All the wiring and converter is now back to stock, which I much prefer. Once the brakes go on I'll pretty much have a 50% UK spec!

The odo is also clocking up and displaying correctly and the dash is all back together, so I'm quite chuffed.

Will put my old Speedo (UK face) and converter up in the for sale section along with all the other gubbins I've accumulated if anyone wants any of it.