Are all years of speedo swappable?

sdw

Registered User
I installed the speedo from my 89 into my 91. After fixing the wires that go into the transmission it works but does not read correctly. It reads substantially under. I'm wondering if there is an issue with using the '89 speedo in the '91.

Regards

Sean
 
I didn't notice a problem with an 89 speedo in our 93.

The speedo's ARE different - you can even tell by looking at the faces, but so far as I know, all 89-95 performance clusters are perfectly interchangeable.
 
Sounds good.

It worked fine when it came out of the Cougar so i will go back and look at the connector.

Sure wish I had a hoist. :(


Sean
 
Stupid question & I'm sorry, not trying to offend, but you didn't replace a 120 w/ a 140 did 'ya? That would cause a lot of difference. There's a thread on here about how to cal the 140 to work in a 120 cluster...

just a thought?
 
Stupid question & I'm sorry, not trying to offend, but you didn't replace a 120 w/ a 140 did 'ya? That would cause a lot of difference. There's a thread on here about how to cal the 140 to work in a 120 cluster...

just a thought?

Actually, there's a thread on how to calibrate a 120 to make it a 145. Or a 160. Or a 200.

The SPEEDOS swap, barring mechanical problems.

They count 8000 pulses as one mile for all of them.

RwP
 
Stupid question & I'm sorry, not trying to offend, but you didn't replace a 120 w/ a 140 did 'ya? That would cause a lot of difference. There's a thread on here about how to cal the 140 to work in a 120 cluster...

just a thought?

No such luck. They are both the same, 120.

I think I will cut the connector off and replace the wires. They wires going into the connector are bare so I'm sure there is probably some issue with a good conductivity.

Sean
 
Stupid question & I'm sorry, not trying to offend, but you didn't replace a 120 w/ a 140 did 'ya? That would cause a lot of difference. There's a thread on here about how to cal the 140 to work in a 120 cluster...

just a thought?

It's a common swap to go from the early model 120 to the late model 140 speedometer. I've done it on both my SCs, and it doesn't require any recalibration...just plug it in and go. Reseting/rebuilding the odometer is the fun part.

David
 
It's a common swap to go from the early model 120 to the late model 140 speedometer. I've done it on both my SCs, and it doesn't require any recalibration...just plug it in and go. Reseting/rebuilding the odometer is the fun part.

David

Ok, I must have gotten confused. I remember reading a thread about swapping and using the GPS for reference then adding resistors in behind the spedo. Come to think of it, maybe it was a decal swap only? I'm getting older & my memory doesn't work as well as it used to :p
 
AFAIK, they're all interchangeable from '89 - '96.

Is your transmission / rear gear / tire size different between those two cars?
 
Ok, I must have gotten confused. I remember reading a thread about swapping and using the GPS for reference then adding resistors in behind the spedo. Come to think of it, maybe it was a decal swap only? I'm getting older & my memory doesn't work as well as it used to :p

Correct...you can put a 160 or even 180 mph decal on it and do a recalibration using resistors or something. I read that same article and it sounded a little too technical for me.

There used to be a device made by Cyberdyne to electronically recalibrate the speedometer when you changed tire diameters and rear gears but they are no longer making it. Now you just have to settle for close, by doing a speedometer gear swap on the transmission.

David
 
Is your transmission / rear gear / tire size different between those two cars?


The tires are larger but the diameter is very close not enough to account for the difference.

I'm sure it is a resistance issue with bad wiring. We'll see what happens after I improve that then if I need to make a speedo gear switch I will.

Regards

Sean
 
All 89-96 MN-12 use VDO speedos and they are all interchangeable. I bet since Porsche uses VDO too you could use theirs too (guts not the face).
 
Sean, i have a spare cluster or two (just got to dig them out), if you want a third speedo to try out let me know.
 
I had 7 or 8 speedos that needed to be tested.....

I wanted to make sure the trip odometers were working....:rolleyes:

I would drive a mile or two and swap each unit out.....

One thing I did notice was that most of them were 5 or 10 mph off....
 
The tires are larger but the diameter is very close not enough to account for the difference.

I'm sure it is a resistance issue with bad wiring. We'll see what happens after I improve that then if I need to make a speedo gear switch I will.

Regards

Sean

LOL 3/4 of an inch in tire height difference and your speedo will be off 5mph
 
LOL 3/4 of an inch in tire height difference and your speedo will be off 5mph

The speedo is off 30 kmh at 90. So reads 60 going 90.

We'll see what happens after I clean up the wiring. The difference in tire diameter is .55" according to a tire calculator should mean it reads 2kph high at 60 which would be ok.

Regards

Sean
 
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Sean, i have a spare cluster or two (just got to dig them out), if you want a third speedo to try out let me know.

Kevin:

The other speedo's I have, have the center pins broken so I may have to take you up on that if cleaning up the wiring doesn't help.

Sean
 
I'll try to look them out tomorrow between pulling my hair out in fixing my '96's steering column :) (the good ol' can't shut your car off issue)
 
I'll try to look them out tomorrow between pulling my hair out in fixing my '96's steering column :) (the good ol' can't shut your car off issue)

I'll let you know what happens this week when I get a chance to crawl under the car.

Sean
 
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