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scorpydude
Joined: Mon Nov 01, 2010 9:47 am Posts: 286 Location: South East Brisbane
Vehicle: 02 GV SQ625 + 84 Sierra SJ410
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 Posted: Wed Sep 28, 2011 1:44 am |
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I read on a dodgy website (forgot to bookmark sorry) that the SJ410 has a way to calibrate the speedo.
Can anyone confirm this before I pull out my dash/cluster ?
The website claimed there was something you could turn to increase or decrease it or something along those lines.
(I'm aware I can buy a Marks adapter but they are well overpriced and are hard-set ... not allowing you to adjust it at a later date after new tyres/gearing without purchasing another... so I would never waste my money on one of those)
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Reubs
Joined: Wed Sep 09, 2009 11:30 pm Posts: 1522 Location: Brisbane
Vehicle: SJ80, SE416
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 Posted: Wed Sep 28, 2011 2:19 am |
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Have you spoken to an instrument shop?
I was given a business card for this place once upon a time...
http://ottoinstruments.com.au/
Never dealt with them though.
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royce

omnipotent being
Joined: Sun Jun 11, 2006 11:30 pm Posts: 17216 Location: Pluto
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 Posted: Wed Sep 28, 2011 2:29 am |
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Calibrate is not adjsut to suit different rolling diameters!
The whole system is based on a revolution of the wheel covering X amount of distance, with this going all the way up the line to teh odometer, the needle moves by way of magnets pulling it along and spring tension restricting how far it moves, you can adjsut this tension and yeah sure you can fiddle with it to get it right in one spot but it will still be out in others and still wont read distance proplery
but if by chance you are using 4.11 diff gears but now with 31" tyres you can use the speedo drive gears from a WT transfer and it will read spot on, the distance per rev on 31" and 4.11 is the same as 205/70 and 3.7
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scorpydude
Joined: Mon Nov 01, 2010 9:47 am Posts: 286 Location: South East Brisbane
Vehicle: 02 GV SQ625 + 84 Sierra SJ410
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 Posted: Wed Sep 28, 2011 3:01 am |
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Thanks Reubs and Royce.
Looks like the only proper way to fix this mechanical speedo in a way that allows me to adjust it in the future easily is to find a decent speedo gearing device.
As I don't fall into that critera you mentioned Royce I'll give the link Reubs posted a go.
I'm hoping to spend under $100 for a device that lets me calibrate my speedo at will. Anything over that is overpriced IMO given the design/parts needed to create such a device.
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scorpydude
Joined: Mon Nov 01, 2010 9:47 am Posts: 286 Location: South East Brisbane
Vehicle: 02 GV SQ625 + 84 Sierra SJ410
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 Posted: Wed Sep 28, 2011 3:08 am |
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Well just gave them a call.. $200 for a electronic speedo box (takes mechanical cable and outputs mechanical cable) that allows them to adjust it but I couldn't adjust it myself without the software. That doesn't include installation.
Yeah stuff that.
Royce + Reubs... what are you thoughts if I made a new paper backing for the speedo?
I've done some testing and found the following..
Car speed from GPS (km/h) / Speedo reading (km/h)
90 / 100
80 / 90
I haven't testsed below that.
Could I just take a scan or photo of the backing speedo paper insert and then change the numbers by -10 on a computer ? so make 100..90 then 90..80 etc?
Or would i still suffer the same problem where at lower speeds it might not be accurate. Eg 50km/h car speed (GPS) might not be 60km/h speedo speed?
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scorpydude
Joined: Mon Nov 01, 2010 9:47 am Posts: 286 Location: South East Brisbane
Vehicle: 02 GV SQ625 + 84 Sierra SJ410
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 Posted: Wed Sep 28, 2011 3:10 am |
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I found these... (please see attached file)
It looks like someone has already attempted this before for 31" wheels?
Shame they are in miles per hour.
You do not have the required permissions to view the files attached to this post.
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Reubs
Joined: Wed Sep 09, 2009 11:30 pm Posts: 1522 Location: Brisbane
Vehicle: SJ80, SE416
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 Posted: Wed Sep 28, 2011 4:03 am |
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scorpydude wrote: I found these... (please see attached file)
It looks like someone has already attempted this before for 31" wheels?
Shame they are in miles per hour.
PM Sent...
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royce

omnipotent being
Joined: Sun Jun 11, 2006 11:30 pm Posts: 17216 Location: Pluto
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 Posted: Wed Sep 28, 2011 4:12 am |
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There is a whole other (recent) thread dedicated to doing that, maybe go find it 
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mrw82

az supporter
Joined: Tue Jul 03, 2007 11:30 pm Posts: 1350 Location: stuck in a hole. not off road, just deception bay.
Vehicle: snotbox, 84 LWB sierra 1 litre
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 Posted: Wed Sep 28, 2011 4:56 am |
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chris just drive it as is. it's a sierra, it doesn't have to be perfect. and when your tyres wear out go up a size and it'll bring it closer to the GPS speed. (bigger tyres will make you go faster then your speedo says your going)
With my 1 litre running 30" tyres my speedo reads within 2km/h of a GPS.
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