Renix 120 MPH Speedo?

[bad_idea]

Well...  Lots of traffic on this thread today.  To answer the questions about why I need a speedo that reads that high.  I plan to build the truck as a street rod/race car/fun toy.  Going to drop it 3-4 inches and slap a SBC 350 in it.  I plan to have the truck (safely, in controlled environment) over 85 MPH often enough.  I guess at a drag strip I don't need a speedo as the track will have the speed listed.  But still nice to have.  Also, not sure how a speedo will act if you routinely bury it.  Will that mess up the cal on it?  I'm grown, so I do not plan to run it on public roads over the speed limit by that much.  

[Jeep Driver]

Jump to 3:00. 

 

Create a standalone speedo, plug it in when you want to use it, stick it to the dash or windshield. 

 

And BS on GPS fail, I use GPS all the time here in the mountains and rarely find any dead spots. 

 

As for burying your current speedo? who cares? 

 

You'll find multiple examples of GPS speedos on YT, all very smooth and accurate. 

 

 

[Jeep Driver]

Mini gauge on the A-pillar. 

 

 

[gogmorgo]

I've had tall trees and bad weather screw up GPS. Driving along the side of rock faces, I've had satellite radio cut out for several miles at a time. Not too long ago we had a rescue attempt fail because someone's spot tracker was indicating a location four miles away from where they were. Maybe it's because I'm further north and satellite signals need to come at more of an angle for me, maybe your mountains aren't all that tall compared to mine... I dunno. But it's definitely not something I'd want to rely on. 

[512tr]

A early XJ HO electronic speedometer can easily be used in an Renix MJ.  These speedometers are “stand alone”, and do not have to be wired via the HO PSM.

[gogmorgo]

What's a PSM and why the funky font?

[512tr]

Sorry my mistake....PCM (Power Control Module).

 

XJ  export cars to Europe had both mph/km/h speedometers 120mph/200km/h 

 

Have some MJ/XJ/ZJ/WJ instruments on my shelf

 

Edited September 26, 2018 by 512tr

[gogmorgo]

Figured since the topic came up again I might as well post up a pic of the 200km/h speedo. 

If you look closely, the lines go beyond 200 to 210km/h; near as makes no difference 130mph. 

[HOrnbrod]

10 hours ago, 512tr said:

XJ  export cars to Europe had both mph/km/h speedometers 120mph/200km/h

 

Yes they did, and I'm not sure why. Maybe the Mopar/AMC engineers thought the export Jeeps would run faster across the pond?  

 

But seriously, I think it was a marketing tool that would hopefully impress prospective buyers.

[kryptronic]

20 hours ago, HOrnbrod said:

 

Yes they did, and I'm not sure why. Maybe the Mopar/AMC engineers thought the export Jeeps would run faster across the pond?  

 

I've always thought this was due to the speed limit being 55 in the US, and much higher, and in some cases unlimited, in Europe.  Just my own hypothesis on the matter.

[Minuit]

6 hours ago, kryptronic said:

 

I've always thought this was due to the speed limit being 55 in the US, and much higher, and in some cases unlimited, in Europe.  Just my own hypothesis on the matter.

The gov't mandated a top speed of 85mph on speedometers for a few years after the national speed limit was passed. I think the actual requirement for an 85mph speedo was lifted in the early '80s. Not sure why everyone stuck with it for so long. That's also why it was so common to see 55 mph specially marked on speedometers for a long time.

 

Also, if you retrofit a UK market speedo into a US cluster, you don't need to do any electrical work. There's an adapter you need to transfer over to the UK speedo, but nothing else. Totally worth it - if for no other reason than to have something different - especially if you manage to luck out and find one on eBay UK that's within 100 miles of your truck's actual mileage.

[512tr]

As Minuit stated, the max 85mph US speedometers was a political BS regulation, and had nothing to do with the cars max speed.

 

https://www.yahoo.com/news/question-of-the-day-why-did-1980s-cars-have-233212628.html

 

EU did have other regulations, speedometers should show the max speed the cars was capable for under ideal conditions.

[bad_idea]

4 hours ago, Minuit said:

especially if you manage to luck out and find one on eBay UK that's within 100 miles of your truck's actual mileage.

 

Am I the only one that doesn't care what the Odometer says?   

 

So, I can swap in the UK market speedo into my Renix cluster and run a electric speedo?  I assume I replace the cable with a couple wires to a VSS in the transfer case?  I assume I would pull the VSS and wiring from any Cherokee from 91-95 or so?

 

I'm not in a big rush on the speedo, still building the garage that I will do the motor swap in.  Build the garage, move into the garage, catch up on projects on my other vehicles, catch up on the honey-do list, then I can start on the MJ.  Ugh.  So I will keep an eye out for a UK market speedo at a reasonable price if I can make it work with minimal headache.

[Minuit]

16 hours ago, bad_idea said:

 

Am I the only one that doesn't care what the Odometer says?   

 

So, I can swap in the UK market speedo into my Renix cluster and run a electric speedo?  I assume I replace the cable with a couple wires to a VSS in the transfer case?  I assume I would pull the VSS and wiring from any Cherokee from 91-95 or so?

I took a peek through the '91 FSM and it looks to me like the '91 speedometer is electrically independent of the ECU (the VSS output leads to splice G7 which branches off to the ECU, cluster, and some other things). That's only part of the problem, and I very strongly doubt that the HO speedometer would fit in a Renix cluster, not to mention that the Renix cluster has a different connector for the gauges and obviously won't have any of the traces on the PCB for the electronic speedometer. Not saying it's impossible, but it would definitely require some custom work.

 

Also, the VSS changed in '93 from a two-wire reed switch to a three wire sensor which I know nothing about. The clusters are compatible from 91-96 though.

[512tr]

Some  pictures of the mechanical and electronic speedometer

The electronic is from a -92 XJ, the mechanical from a -88 XJ

It should be doable to do a custom job to fit the electronic in the Renix housing.

The wiring is simple, only 3 wires.

[kryptronic]

On 9/28/2018 at 1:04 AM, Minuit said:

Also, if you retrofit a UK market speedo into a US cluster, you don't need to do any electrical work. There's an adapter you need to transfer over to the UK speedo, but nothing else. Totally worth it - if for no other reason than to have something different - especially if you manage to luck out and find one on eBay UK that's within 100 miles of your truck's actual mileage.

 

Do you have a source/part number for the adapter you reference?  I've got a UK market 120MPH speedometer in transit to me, and am keen to do the swap the right way, and document the process in a write-up here on CC.  Thanks.

[Minuit]

4 hours ago, kryptronic said:

 

Do you have a source/part number for the adapter you reference?  I've got a UK market 120MPH speedometer in transit to me, and am keen to do the swap the right way, and document the process in a write-up here on CC.  Thanks.

The "adapter" I refer to is already attached to the US speedometer. You just need to put it on the UK one.

 

Near the bottom of this page where I start talking about radios

[kryptronic]

52 minutes ago, Minuit said:

The "adapter" I refer to is already attached to the US speedometer. You just need to put it on the UK one.

 

Near the bottom of this page where I start talking about radios

 

That's awesome.  Thank you.  I really appreciate you documenting the swap.  I'll be following your instructions when I do it.

[Jeep Driver]

Scroll down to two wire..........makes more sense to me now. 

 

https://www.classicinstruments.com/tech-info/testing-speedometer-signals.aspx