Jump to content
The mkiv Supra Owners Club

Anyones speedo out???


SUPRACHRIS
 Share

Recommended Posts

Most are miles out as standard - at 80mph on the speedo I'm doing around 71mph on my GPS, my motorway cruising speeds have risen a fair bit since I got that :)

 

I'm not sure how to fix it but fitting bigger wheels and increasing the rolling radius a bit will help so you have probably already helped things.

Link to comment
Share on other sites

Yup - pretty much all supra's read 5 mph or up to 10% out from what they say!

 

Mine's on 17's with stock size tyres but the original car came with 16's back then. When I got it my car would read 100 but be doing 90. 70 was about 63, 50 about 45, 30 about 28. So it got worse higher up. Since fitting new dials I had to put the needle back on, set it at 0 and it was way out in test on driving. went out with covers off, set cruise at 40, long straight road, shoved needle on in right place so now 30, 40 and 50 are pretty spot on. 70 is about 68. 90 is about 85 and 100 is about 93-94. So much better!

 

Even my bro-in-laws golf V5 MKIV is out, at 85 on clock he's doing about 81-82 by GPS.....

Link to comment
Share on other sites

Yep mine is out too - i have the Origin B2 gps unit and 180mph on the speedo is actually 169mph.......

 

At lower down speeds its not quite so bad i.e 20mph on the speedo is about 18-19mph on the GPS unit....

 

i think they come like this from the manufacturer but i spoke to Leon when i was down last month and he said there is an adjustment on the back on the speedo unit ???

 

can anyone shed any light?

 

Jonny

Link to comment
Share on other sites

All analogue gauges have an accurate and innacurate range. Thats why speedo's generally have a huge amount more mph than a car can do on them. the second third of a gauge is its accurate zone anything in the rest is surprisingly innacurate. Where I used to work all gauges of any description were calibrated annually. As our speedo's are never calibrated as its not required for them to be calibrated its hardly surprising that over time their calibration drops off. Those delimiters and mph converter boxes that are available and probably allready on most j-specs are alledgedly capable of speedo adjustments ie calibration.

Link to comment
Share on other sites

Originally posted by dangerous brain

Those delimiters and mph converter boxes that are available and probably allready on most j-specs are alledgedly capable of speedo adjustments ie calibration.

Well some are, some aren't. The cheap no-name ones usually don't have any facility to correct the speedo accuracy. I know the TRL ones do have that feature though.

 

 

Edited to add the following from the TRL web sitehttp://www.thor-racing.co.uk/TRL/dsc.html :

The TRL DSC provides calibrated outputs adjustable by +/-10% in approx 1.5% increments
Link to comment
Share on other sites

  • 4 weeks later...

Well my Speedo is spot on now! I finally got aroung to adjusting the calibration on the TRL speedo conversion thing.

Drove along the motorway with the GF reading the GPS and me saying "Now" when it got to exactly 70mph and her telling me the true speed as per the GPS. A couple of adjustments on the TRL unit later and it's spot on at 70mph and 1mph out at 30mph.

 

Good bit of kit that TRL stuff.

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.

 Share

×
×
  • 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.