Speedo error

[feralbass]

Hi guys,

This may be a dumb question but my speedo is out compared to the GPS. 10 k's short @ 80k's. (out across all speeds)

Tyres are Bridgestone desert duellers 235 17 16.

Can this be corrected.

Thanks for any replies, cheers, John

 

[longy509]

Yeh mate mine is out aswell speedo says 100 gps says 90kmh

 

[steve1961]

yeah , put 265x75's on then it reads 100 per speedo and gps , iam sure these things ware 265 boots in other countries because thats what the bloody speedo is calibrated for

 

[Old.Tony]

Don't pay too much attention to the needle - the needle itself is inaccurate.

If you drive along with a tool that can read the ECU's data, you'll be surprised to find that on standard tyres, the ECU is remarkably close to the GPS speed (which is accurate to about 1%). This means your ECU is pretty much accurate.

The needle is deflected by a voltage applied to a coil which causes it to push against a magnet and thus deflect the needle. With modern technology it should be possible to be much more accurate but because the Australian Design Rules allow for "10% plus 4km" of deviation ABOVE (but none below, so your speedo is NOT allowed to read SLOWER than the vehicle is actually going) most dealers will tell you to take a flying leap.

I'm serious. I asked my dealer, and they said "nahh, it's within ADR specs so it's not going to be changed and Nissan won't foot the bill for it if you insist because it's not out of spec". Blame the stupid ADRs.

If you change tyre size and get an apparent accuracy on the needle, you'll find that your ECU no longer accurately knows the speed, or the distance travelled.

The short answer is - don't rely on the needle, get a GPS and have it display your speed for you.

 

[steve1961]

Don't pay too much attention to the needle - the needle itself is inaccurate.

If you drive along with a tool that can read the ECU's data, you'll be surprised to find that on standard tyres, the ECU is remarkably close to the GPS speed (which is accurate to about 1%). This means your ECU is pretty much accurate.

The needle is deflected by a voltage applied to a coil which causes it to push against a magnet and thus deflect the needle. With modern technology it should be possible to be much more accurate but because the Australian Design Rules allow for "10% plus 4km" of deviation ABOVE (but none below, so your speedo is NOT allowed to read SLOWER than the vehicle is actually going) most dealers will tell you to take a flying leap.

I'm serious. I asked my dealer, and they said "nahh, it's within ADR specs so it's not going to be changed and Nissan won't foot the bill for it if you insist because it's not out of spec". Blame the stupid ADRs.

If you change tyre size and get an apparent accuracy on the needle, you'll find that your ECU no longer accurately knows the speed, or the distance travelled.

The short answer is - don't rely on the needle, get a GPS and have it display your speed for you.

Yes pretty true what you have written Tony , as your probably aware on the scan gauge 2 you can adjust the speed , for tyre sizes , i have the scan guage as well it reads same as the gps

 

[steve1961]

Note to the above ^^^ the speedos are as useless as balls on a snake

 

[Bazz]

Yeah mine brand new is about 10% out Nissan say its fine within the industry standard.

I think its bullshit its dangerous, I have no idea what speed i'm doing without a GPS. When I first went on the highway I stayed in the left hand lane and sat just above 100 according to my speedo. People were sitting on my ass and tailgating me, so thought something was up.

Now to reduce road rage I have to try and work out 10% more and do that speed. I think its terrible that something so small but so vital is so wrong.

 

[steve1961]

Yeah mine brand new is about 10% out Nissan say its fine within the industry standard.

I think its bullshit its dangerous, I have no idea what speed i'm doing without a GPS. When I first went on the highway I stayed in the left hand lane and sat just above 100 according to my speedo. People were sitting on my ass and tailgating me, so thought something was up.

Now to reduce road rage I have to try and work out 10% more and do that speed. I think its terrible that something so small but so vital is so wrong.

Yes it sucks , but my Triton was the same , 265 tyres / scan gauge , or gps , never rely on the speedo , i have 2 fines in 3 months to prove that guessing the speed don't work

 

[Bazz]

yeah when these tyres burn out I will go for 265's.

Sucks about the fine mate, I have heard it can be corrected cheaply

 

[Billy the Kid]

Speedo Error

Has anyone tried these to overcome the speedo error.

http://www.youtube.com/watch?v=0d56QxwcCP4

 

[KraftyPg]

Jaycar sell a kit that will adjust speedos, not sure if anyone here has tried one in a Nav but they do work and aren't that difficult to install.

Failing that learn how to do simple subtraction and work out actual speed from shown speed - error. That also isn't difficult and costs less than any Jaycar kit.

 

[Old.Tony]

The Jaycar kit might work on the D22 but not on the D40. The D40 works out the vehicle's speed as an aggregate of the ABS inputs from each wheel. The Jaycar kit needs the input to be from the revolution sensor on the output shaft of the gearbox (ie D22 and pre-2005 D40s). It's purely a pulse rate adjuster - very clever idea, in truth. Just some smart-ass in at Nissan decided to change where it got the info from.

I find the best thing to do is just rely on the GPS speed indication.

 

[KraftyPg]

Someone sells a kit for newer cars I've seen it listed somewhere for about $120 with the super duper sales pitch that "it's cheaper than a speeding fine" but I wasn't interested because I can do maths.