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The mkiv Supra Owners Club

Is this my KPH to MPH converter


Soaruss

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Is the pic attached, my KPH to MPH converter??

Also can anyone recognise the make from the pic?? theres no writing on it.

 

I have my suspisions that its faulty because speedo doesnt read true.

 

Whats the best converter to replace it with??

I'm not bothered about odo converter.

 

Doh yeah best if I add pic.

 

image

Edited by Soaruss
add pic (see edit history)
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I will have a better look tomorow but this is what I can remember.

 

one wire, the one on the far right just under the wiper stalk is screwed to the back of the speedo.

one wire goes into the blue plug that clips into the back of the speedo.

A couple of wires go elsewhere.

one wire (think its black) goes up behind the dash and over towards the glove box then down out of site.

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Heres how far out my speedo is.

 

I have checked it against a sat nav.

 

Sat nav reading 30mph

My speedo 40mph

 

Sat nav reading 40mph

My speedo 52mph ish

 

Sat nav reading 50mph

My speedo 65mph

 

Sat nav reading 60mph

My speedo 77mph ish

 

Sat nav reading 70mph

My speedo 88mph ish

 

Sat nav reading 80mph

My speedo 100mph

 

The wires from the converter are

 

Blue goes to passenger footwell

 

Red screwed to back of speedo

 

Black screwed to back of speedo

 

Yellow to blue plug in back of speedo

 

Orange goes into loom

 

If I replaced to converter would it wire up to same points as the one in now.

Or could someone local to me wire it in for me ??

I'm not competant with electrics.

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What does the speedo read when you are stationary; both with the engine running and when it's completely switched off (key removed)?

 

It looks to me as though the needle has been moved, AND the speedo convertor is adding a % error as well.

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Some basic calculations back up what I suggested:

 

Take the real speed (sat nav), add 20% to it (the error from the speedo convertor) and then add a fixed 4mph (needle out of position) and you get the readings your speedo is displaying:

 

Sat Nav | Speedo

30 | 40

40 | 52

50 | 64

60 | 76

70 | 88

80 | 100

 

Are your wheels massively different rolling circumference to stock?

You'll need to adjust the speedo convertor either way - however not all are ajustable.

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My car came with a speed converter like that. I think they're quite cheap (they don't adjust the PAS sensitivity properly), and my one didn't last very long before it croaked.

 

I replaced it with a DSC+TSD from Thor: not cheap, but it does what it says on the tin, and does it well. It takes care of all speed-related anciliaries like PAS, active spoiler, etc.

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Are Thor selling these units again? They stopped making them for ages.

Dunno. I suspect they would if the demand was there (i.e. people ring up and ask for them). It's not hard or costly to them, just an EPROM, a plastic case for a few pence and some bits of wire. ;)

 

Failing that, someone on here was selling one a while ago, can't remember if it went or not. I'm not interesting in buying it but any interested parties can go hunting for it, of course. :)

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What does the speedo read when you are stationary; both with the engine running and when it's completely switched off (key removed)?

 

It looks to me as though the needle has been moved, AND the speedo convertor is adding a % error as well.

 

Speed reads 0 when stationary :search:

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