Jump to content
SAU Community

Calibrating Speedo

ShonE

By ShonE,
in Four Door Family & Wagoneers

 Share

Recommended Posts

ShonE Explorer

ShonE

Posted
Posted

Hei guys

Realized my stagea's speedo is reading wrong but some margin. Its showing more than im actually traveling, know that traffic is usually slower than the speed limit and even when i was driving 10 over there would still be cars passing by so I took this GPS unit to check it as they are supposed to be accurate and speedo is actually showing more than gps unit. Its like 10 over at 60 and almost 20 over at 100. When speedo is showing 120 GPS says im traveling at some 100-103 kmh...

So was wondering has anyone had similar problem or is this not that common, what causes it and yeah most important how to fix it.

Link to comment
https://www.sau.com.au/forums/topic/437745-calibrating-speedo/
Share on other sites
Duncan Grand Master

Duncan

Posted
Posted

I don't have stock wheels and tyres, but they are about the standard diameter and my speedo was also reading about 10% over.

I put on of these in the car (tapped in near the dash): http://www.jaycar.com.au/productView.asp?ID=KC5435

BTW ADRs specify a speedo must be between 0 and 10% over actual speed....how crap is that?!?

scotty nm35 Grand Master

scotty nm35

Posted
Posted

M35's are notorious for the speedo reading high, I run 235/45/18's and they still read 10k's over at 100. I hoped the Nismo cluster would be more accurate, but it wasn't.

The ecu is reading the correct speed according to my informeter, but the speedo is still out, so I just use the informeter for accurate speed measuring.

Blek Collaborator

Blek

Posted
Posted

I don't have stock wheels and tyres, but they are about the standard diameter and my speedo was also reading about 10% over.

I put on of these in the car (tapped in near the dash): http://www.jaycar.com.au/productView.asp?ID=KC5435

BTW ADRs specify a speedo must be between 0 and 10% over actual speed....how crap is that?!?

Hey Duncan, was it difficult to splice in & get accurate?

My speedo is approximately 10% out as well, which is a PITA for me, with 110kph limited factory cruise control :(

ChrisB Rising Star

ChrisB

Posted
Posted

My ARX runs 225/55/18 as per the placard and when the spedo is at 110 the car is actually doing 103 (per my GPS)

The V36 is out by about the same. I reckon they are built like this to slow people down.

Now I figure if i run 245 45 18 as suggested above, this will reduce my rolling diameter from 2214mm down to 2129mm and throw the spedo out by another 4 kms/hour.

I figure that if I were to run 235 55 18 then at 110 on the spedo the car would be going around 105 kms an hour.

Found some Dunlop SP Sport 235/55/18 100V LM703 for a reasonable price. Anybody running these?

245 55 18 would produce about 107 kmh at 110, an error of only 3kmh but this tyre size is likely an off road tyre and if it didn't touch my plastic guards would sound like a truck anyway!

Daleo Grand Master

Daleo

Posted
Posted

My ARX runs 225/55/18 as per the placard and when the spedo is at 110 the car is actually doing 103 (per my GPS)

The V36 is out by about the same. I reckon they are built like this to slow people down.

Now I figure if i run 245 45 18 as suggested above, this will reduce my rolling diameter from 2214mm down to 2129mm and throw the spedo out by another 4 kms/hour.

I figure that if I were to run 235 55 18 then at 110 on the spedo the car would be going around 105 kms an hour.

Found some Dunlop SP Sport 235/55/18 100V LM703 for a reasonable price. Anybody running these?

245 55 18 would produce about 107 kmh at 110, an error of only 3kmh but this tyre size is likely an off road tyre and if it didn't touch my plastic guards would sound like a truck anyway!

You're right Chris, the tyre set up I have suggested won't solve the issue on an AR-X, as they run a larger rolling dia than the RS/RX/AXIS. Do they use a different Speedo cluster?

Using a tyre size guide, should allow you to plug in easily available tyre dimensions, and reduce the error.

Duncan Grand Master

Duncan

Posted
Posted

Blek it was pretty straightforward to install, the wiring is actually marked on the rear of the cluster so I just intercepted the signal on the way into the dash. AFAIK in most of these cars the signal goes from gearbox to dash and then everywhere else (eg ECU and cruise control) so the dash is a good place to intercept.

The only thing to be aware of is that the link I posted is a kit, so you will need a soldering iron and some patience to put it together.

I'd normally prefer to just change tyre size (am doing that in the leaf ATM to fix the same issue) but that's expensive if you aren't already due for new tyres anyway.

ChrisB Rising Star

ChrisB

Posted
Posted

You're right Chris, the tyre set up I have suggested won't solve the issue on an AR-X, as they run a larger rolling dia than the RS/RX/AXIS. Do they use a different Speedo cluster?

Using a tyre size guide, should allow you to plug in easily available tyre dimensions, and reduce the error.

I have a feeling that the cluster may be different.

when I've seen Nismo clusters on Yahoo, if I remember correctly, they state NOT ARX.

  • Like 2

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      Welp, good to know. Will have to wait awhile until steady hands with drills and taps are available. In other news, these just arrived! I will weigh them for posterity.
    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      100% the factory sender is tapered, that is how it seals (well, that and teflon paste or tape)
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      Thanks folks - I've saved a few links and I'll have to think of potential cable/adapters/buying fittings. First step will be seeing if I can turn the curren abortion of a port into something usable, then get all BSPT'y on it. I did attempt to look at the OEM sender male end to see if it IS tapered because as mentioned you should be able to tell by looking at it... well, I don't know if I can. If I had to guess it looks like *maybe* 0.25 of a mm skinnier at the bottom of the thread compared to where the thread starts. So if it is tapered it's pretty slight - Or all the examples of BSPT vs BSPP are exaggerated for effect in their taper size.
    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
×
×
  • Create New...