Jump to content
The mkiv Supra Owners Club

Help with my speedo converter


T14PPA

Recommended Posts

Hi i bought the speedo converter below and fitted it and it seems to be reading in miles now however the speedo is not moving smooth. It goes up and down around the correct mph. Anyone used this one or can suggest anything that may be wrong. image.jpg

Link to comment
Share on other sites

Guy I work with fitted mine, I no he wired it under the car near the front of the gearbox......

 

Can look tomorrow if any help......

 

Mate that would be massive help mate. If you could get pictures and stuff i would be so grateful

Link to comment
Share on other sites

To be honest i only tried it up to 40mph. Why do you ask that?

 

when I first got a supra I played around quite a bit with these and discovered that most use a simple pic processor to do what's required. Although the programming is easy, a couple of the ones I played with gave rubbish results at low speed and the guy I know who is bit of a pic processor programming guru tells me it's quite hard to get a nice smooth response without good knowledge of programming. He makes them for a company who installs ballistic protection to various cars and have bigger tyres fitted, thus the speedo needs correcting and knows what he's talking about. He did give me a long explanation of why the less engineered ones tend to give a less than smooth output at lower speeds, and at the time it made sense, but I have slept since then and can't really remember. I can find out if required.

 

I was planning to make one that didn't just give a scaled output for both speedo and autobox, but gave the true output for the ecu/atf right up to the limit when it clamped, but never got around to it. I believe this is how the better ones like the Thor one works, the cheaper ones I tried merely provided a scaled output.

Link to comment
Share on other sites

It shouldn't really matter where in the circuit you put it tbh. The description of that one suggests its pretty basic and providing a simple scaled output of what the gearbox is providing., ie. DC supply, input and single output, that's fine for the speedo but not so good for everything else, you really need an output that provides the ECU with the correct info from the sensor right up to just before the limit point when it should clamp and hold at that point, until what's going in drops back to below that point when it continues to provide the correct info.

Link to comment
Share on other sites

From what i remember positive and earth are on the the back of dials. Output is connected to one of the wires on the odometer plug and input on the speed dial plug. Does this sound right?

Yes that's correct, there is a detailed thread on here somewhere that provides the exact details, but again, that description is of a simple 4 wire type which will get your speedo right and stop the speed limiter cutting the engine, but not really the way to do it IMO. Try and find one with a clamped output as well, that way you are only feeding your ECU with bum info once you get to the 112mph or whatever it is. Am sure loads of people have used the 4 wire ones with OK results, but its not the way to do it really, probably not so important on a manual though.

Edited by Shane
Darned auto fill on android (see edit history)
Link to comment
Share on other sites

Yes that's correct, there is a detailed thread on here somewhere that provides the exact details, but again, that description is of a simple 4 wire type which will get your speedo right and stop the speed limiter cutting the engine, but not really the way to do it IMO. Try and find one with a clamped output as well, that way you are only feeding your ECU with bum info once you get to the 112mph or whatever it is. Am sure loads of people have USD the4 wire goes with OK results, but its not the way to do it really, probably not so important on a manual though.

 

Have you ever heard of cartek? Its a little rectangle box with 5 wires. Thats what i use to have. That had ecu signal wire. Is that what you mean? And that go into the the pinky grey wire at the back of odometer if im correct

Link to comment
Share on other sites

Have you ever heard of cartek? Its a little rectangle box with 5 wires. Thats what i use to have. That had ecu signal wire. Is that what you mean? And that go into the the pinky grey wire at the back of odometer if im correct

Was just going to post this.http://www.ebay.co.uk/itm/Speedo-speedometer-converter-chip-E-SVA-IVA-KMH-to-MPH-/380258508684?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item58892c5f8c

 

Yes this would be good.

Link to comment
Share on other sites

Was just going to post this.http://www.ebay.co.uk/itm/Speedo-speedometer-converter-chip-E-SVA-IVA-KMH-to-MPH-/380258508684?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item58892c5f8c

 

Yes this would be good.

 

I should have just stuck with my original and i wouldnt have this problem

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.