kctz Posted March 14, 2007 Share Posted March 14, 2007 I picked up my 04 JDM 350z last Tuesday and whilst on a run today with my GPS Origin B2 and PDA both running, noticed that the speedo (dial and digital) is reading 7mph above the readout on the GPS devices. Is there an easy way to get the speedo calibrated? Is it something I'll have to go to a main dealer for? Thanks[/b] Quote Link to comment Share on other sites More sharing options...
M13KYF Posted March 14, 2007 Share Posted March 14, 2007 You have to allow some discrepancies with any speedo unless to pay to get it specially callibrated. This is one reason why the police have a leeway (10% I think) rate when clocking you while your driving. It common on all cars by the way and piccies of ya z would be nice. If I don't ask plenty others will Quote Link to comment Share on other sites More sharing options...
lomoto Posted March 14, 2007 Share Posted March 14, 2007 I picked up my 04 JDM 350z last Tuesday and whilst on a run today with my GPS Origin B2 and PDA both running, noticed that the speedo (dial and digital) is reading 7mph above the readout on the GPS devices. Is there an easy way to get the speedo calibrated? Is it something I'll have to go to a main dealer for? Thanks[/b] Quite normal mine does the same Quote Link to comment Share on other sites More sharing options...
Zzzz... Posted March 14, 2007 Share Posted March 14, 2007 I believe it is a law thing or legislation that the speed should over-read but never under-read. Also the accuracy changes at different speeds (at low speeds is near enough accurate and as you increase speed, it will start to over-indicate) check it out...this is true on the last 4 cars I have looked at. I also read in a magazine once, that manufacturers can use this "tolerance" to cheat a little on gearing ratios and other speed related "perceived performance", so basically it looks to us as it is doing better than it is actually doing... specially to give better results for fuel consumption. for example, if magazines or customers drive at a constant indicated 70mph, and achieving 40mpg, ( not on a zed of course!!!) actually the fuel consuption figures are for a speed of 63mph, and in reality the guy should be driving at around 77mph , then, the rpm will be higher, the load will be greater and the fuel consumption will be worse... cunning lot car manufacturers... Actually the Z is much better than my old primera, and other cars I have driven, though i think top german cars are much more accurate in general. jee i feel like WikiZzzz... Quote Link to comment Share on other sites More sharing options...
kctz Posted March 14, 2007 Author Share Posted March 14, 2007 Thanks for all your help guys, looks like I'll have to rely on the GPS and turn the computer to outside temperature (the fuel consumption readout's too scary!!). The 10% tolerance thing is interesting and as the car's just had its SVA I suppose my speedo must have been within this limit. For those of you interested, pictures of my new toy attached! It's got an aftermarket exhaust of some sort (the guy at JCImports didn't know what make etc.) and an induction kit...sounds awesome!! Didn't have the BOSE system which was a bit disappointing but did have a Panasonic Carrozzeria head unit (with mini-disc and AV input) with pop-up screen and a separate HDD/ CD/ DVD unit. As you might have guesed the system is JDM specific so I'm going to have to learn Japanese to work out how to store a radio station! It has satnav and a TV which obvoiusly won't work either Quote Link to comment Share on other sites More sharing options...
Zzzz... Posted March 14, 2007 Share Posted March 14, 2007 Interesting about the JDM audio, let us know if you give up on it, and decide to try and get some cash for it... I am currently learning Japanese... (sorry ... trying to learn) Quote Link to comment Share on other sites More sharing options...
rickya Posted March 14, 2007 Share Posted March 14, 2007 Nice car mate Mine did read 5mph out but now doesnt. This was because I changed alloys & changed rolling radius slightly (due to different alloy & tyres sizes), but worked in my favour by making speedo 3 to 4 mph slower which cancelled out initial extra speed reading. Quote Link to comment Share on other sites More sharing options...
westfield Posted March 15, 2007 Share Posted March 15, 2007 How on earth did it pass the SVA then? The VOSA test station I go to tell me that the speedo converters have to be very accurate indeed, and the margin for error is a couple of MPH either way. I suppose it depends on how accurate your GPS receiver is...i.e. how many satellite's/channels it uses ? Ben Quote Link to comment Share on other sites More sharing options...
stuey Posted March 15, 2007 Share Posted March 15, 2007 if your gonna change the wheels to bigger rims you can compensate that wiv the profile.............. the tyre calculator Quote Link to comment Share on other sites More sharing options...
lomoto Posted March 15, 2007 Share Posted March 15, 2007 How on earth did it pass the SVA then? The VOSA test station I go to tell me that the speedo converters have to be very accurate indeed, and the margin for error is a couple of MPH either way. I suppose it depends on how accurate your GPS receiver is...i.e. how many satellite's/channels it uses ? Ben SVA test just makes sure it has a speedo calibrated in MPH then cant check it for accuracy , besides which nearly all speedo's run fast up to about 10% tolerance straight from the factory Quote Link to comment Share on other sites More sharing options...
Sgt Wilson Posted March 15, 2007 Share Posted March 15, 2007 Lovely shiny motor Nick Quote Link to comment Share on other sites More sharing options...
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