Speedo Error?

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Speedo Error?

Postby damien.kal » Thu Oct 30, 2014 1:02 pm

Not sure if this is the right thread to post this, if not let me know.

Hey recently got myself a Facelift 3.0R auto. Noticed that the speed seems to be showing a fair bit slower than what I'm actually driving. Coming from driving my old car at least it certainly feels like that. As well as comparing to local traffic which in an 80 zone seems that every else is going around 90... and on the freeway everyone else is at least 110 usually. Now obviously we don't always stick to the speed limit but it seems kinda weird that pretty much everyone overtakes me on the freeway when I'm going 100. In terms of the wheels and tyres they're the stock spec B 18s with 215 45 18 rubber on them.

Any ideas on whether I'm just crazy or is something else up?

Cheers
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Re: Speedo Error?

Postby WIDELOAD » Thu Oct 30, 2014 4:32 pm

Nope, not crazy. My gen4 was about 8-10km/h out (90 on the speedo was closer to 80 real speed). There is a thread on here about it somewhere.
When I picked up my new wheels i spec'd up a smidgen in size so it's only about 4km/h out now.
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Re: Speedo Error?

Postby KiDo_Tuning » Thu Oct 30, 2014 5:49 pm

Factory size tyre, 100kph on dash is 93kph road speed
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Re: Speedo Error?

Postby damien.kal » Thu Oct 30, 2014 6:55 pm

Ahh that's really weird for factory size to be like that hahaha Thanks a lot for the speedy replies :)
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Re: Speedo Error?

Postby zch91 » Thu Oct 30, 2014 7:48 pm

Pretty standard for most if not all cars these days to have speedo's that read higher than actual speed
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Re: Speedo Error?

Postby GONEWALKABOUT » Thu Oct 30, 2014 7:53 pm

my speedo is 5km/h faster than the speed cameras. I thought legally they had to because if by chance the speedo read slower than your actual speed you would be unknowingly speeding constantly.
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Re: Speedo Error?

Postby Kekotic » Thu Oct 30, 2014 8:45 pm

GONEWALKABOUT wrote:I thought legally they had to because if by chance the speedo read slower than your actual speed you would be unknowingly speeding constantly.

http://www.racq.com.au/cars-and-driving ... o-accuracy
Speedo regulations in Australia
Before 1 July 2006
For vehicles manufactured before July 2006:

An accuracy of +/- 10 percent of the vehicle’s true speed is needed when a vehicle is travelling above 40km/h. This means if a vehicle is travelling at a true speed of 100km/h, the speedo is allowed to indicate a reading between 90km/h and 110km/h.
An odometer accuracy of +/- 4 percent is also a requirement.

After 1 July 2006
From 1 July 2006 all newly introduced models of a vehicle available on the market must comply with the following requirements:

The speedo must not indicate a speed less than the vehicle’s true speed or a speed greater than the vehicle’s true speed by an amount more than 10 percent plus 4 km/h.
The speedo must always read 'safe', meaning the vehicle's true speed must not be higher than the speed indicated by the speedo. So if a vehicle travelling at a true speed of 100km/h, the speedo must read between 100km/h and 114km/h. Another way of looking at this is if the speedo indicates a speed of 100km/h, the vehicle's true speed must be between 87.3 km/h and 100km/h.
There is now no requirement to have an odometer.

From 1 July 2007
All newly manufactured vehicles (excluding mopeds) must comply with these rules.
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Re: Speedo Error?

Postby Manaz » Thu Oct 30, 2014 9:00 pm

zch91 wrote:Pretty standard for most if not all cars these days to have speedo's that read higher than actual speed


It's actually a legal requirement.
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Re: Speedo Error?

Postby bigBADbenny » Thu Oct 30, 2014 11:28 pm

I'm using my www.btssm.com to display corrected speed (and boost etc) on my nav screen. :P
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Re: Speedo Error?

Postby damien.kal » Sat Nov 01, 2014 12:22 pm

Oh wow didn't even know this was a thing hahahaha
Thanks for the insight guys!
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Re: Speedo Error?

Postby Evozn » Fri Nov 14, 2014 12:47 am

KiDo_Tuning wrote:Factory size tyre, 100kph on dash is 93kph road speed


Does this apply to the Outback as well?
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Re: Speedo Error?

Postby muzza » Fri Nov 14, 2014 8:36 am

Evozn wrote:
KiDo_Tuning wrote:Factory size tyre, 100kph on dash is 93kph road speed


Does this apply to the Outback as well?


Its probably close to the same error if normal tyre size is fitted.

Both my current Lib and prev Forester were 6 kays fast on the speedo, ie REAL speed was 94 when 100 indicated.
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Re: Speedo Error?

Postby jp928 » Tue Nov 25, 2014 4:40 pm

6% high seems std for Subys. The interesting part of using an OBD-II reader is coolant temp vs the gauge - my gauge never moves from just below horizontal once warmed up, but OBD shows actual temps vary from 83 to 97C...
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Re: Speedo Error?

Postby GONEWALKABOUT » Tue Nov 25, 2014 4:53 pm

jp928 wrote:6% high seems std for Subys. The interesting part of using an OBD-II reader is coolant temp vs the gauge - my gauge never moves from just below horizontal once warmed up, but OBD shows actual temps vary from 83 to 97C...
jp 98 gtb 6mt wagon.


I have heard that gauges like those seem to be middle happy
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Re: Speedo Error?

Postby jp928 » Tue Nov 25, 2014 9:51 pm

I think you will find that the 'chassis computer' controls all the gauges, rather than the actual gauges being damped or something. As well as the temp not following reality, an OBD-II reader can show you much more accurate speed out of the car's ECU, so I reckon they program the ecu to feed an exaggerated speed figure to the speedo.
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