SUPRACHRIS Posted March 25, 2004 Share Posted March 25, 2004 My speedo seems to be about 5mph out, i think its most likely to be my wheels being 18" with 245/35 front and 275,35 rears. anyone else have this prob and know how to adjust it:) Quote Link to comment Share on other sites More sharing options...
michael Posted March 25, 2004 Share Posted March 25, 2004 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. Quote Link to comment Share on other sites More sharing options...
SkyJawa Posted March 25, 2004 Share Posted March 25, 2004 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..... Quote Link to comment Share on other sites More sharing options...
jjgage Posted March 25, 2004 Share Posted March 25, 2004 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 Quote Link to comment Share on other sites More sharing options...
apoc_reg Posted March 25, 2004 Share Posted March 25, 2004 Mines out too! Gets worse the faster i go then at around 130(on the clock) it drops to zero!! Very odd. Quote Link to comment Share on other sites More sharing options...
Aerotop Dave Posted March 25, 2004 Share Posted March 25, 2004 I was doing 80 on the M11 the other day and it seemed everyone was overtaking me. I can't believe they were all doing 85 or 90. Quote Link to comment Share on other sites More sharing options...
Roy Posted March 25, 2004 Share Posted March 25, 2004 mines 12mph faster than what my gps says ... on 18's Quote Link to comment Share on other sites More sharing options...
Justin Posted March 25, 2004 Share Posted March 25, 2004 Yep, mine read 120 when I crossed the 1/4 line at Woodbridge but my ticket said 111.6. Last year read 168 and ticket said 158. (not 1/4) (recently - copper said 140, I said 69 ) just a wee joke there officer not really. Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted March 25, 2004 Share Posted March 25, 2004 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. Quote Link to comment Share on other sites More sharing options...
Jake Posted March 25, 2004 Share Posted March 25, 2004 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 Quote Link to comment Share on other sites More sharing options...
dude Posted March 25, 2004 Share Posted March 25, 2004 The speedo in the black UK i took to woodbridge was abou 5-7 mph out at 163 mph !!! Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
apoc_reg Posted March 25, 2004 Share Posted March 25, 2004 speaking of which is there a way to correct to MPH without a box? Mine was converted when i got it but not delimited. I brought a TRL one with the plan of removing the old one but couldnt find it!! had the entire dash out! Quote Link to comment Share on other sites More sharing options...
Jake Posted March 25, 2004 Share Posted March 25, 2004 Originally posted by apoc_reg I brought a TRL one with the plan of removing the old one but couldnt find it!! had the entire dash out! Did you look at the ECU? IIRC it's possible to install a SLD there as well. Quote Link to comment Share on other sites More sharing options...
ChrisR Posted March 26, 2004 Share Posted March 26, 2004 Both my Import Supra and GT-Four are consistantly 5mph out and for info so is the wifes UK SPec Yaris. All measured on the same GPS Snooper. A tranny Van i hired recently was approx 3 - 4 mph out, i sh*t you not Quote Link to comment Share on other sites More sharing options...
Jake Posted April 19, 2004 Share Posted April 19, 2004 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. Quote Link to comment Share on other sites More sharing options...
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