Mustang Owners Club Australia Forum
Generation 6 - S550 Discussion Area => Tech Torque Post 2015 => Topic started by: Blacksally1 on January 31, 2019, 02:15:01 pm
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The speedo in my car is not accurate and is out, by a lot.
I have checked on my Garmin GPS and a couple of phone apps and at the indicated speed of 100kph I am actually doing only 93kph. I have to set my Cruise control at 118kph to do 110kph on the highway.
I have 20 inch wheels fitted but the actual total diameter is stock. My friends new 2018 Mustang is the same. Apparently it is common.
This really is a PITA, you have no idea what your actual speed is, causes stress every time I drive past the police or a speed trap.
My Toyota Landcruiser is dead accurate, My Nissan Patrol ute is dead accurate, My SV6 Commodore is pretty close, the daughters Subaru Outback is spot on.
Has anybody had Ford Australia fix this issue? I see that in the States a re-flash of the ECU is available to fix this problem.
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My wife's 2010 subaru impreza is the same, 117km/h on the speedo is actually 110km/h.
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https://www.youtube.com/watch?v=XpA57X4Em8Y
Check this out, he is not for everyone but often has some good info.
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F%@cking Santa Claus is giving out car advice.
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Mine is out by 3km/h at an indicated speed of 40 km/h.
As I understand it that is normal. I would guess that then correlates to 7.5 km/h at 100km/h.
I only really notice anything wrong when going through those roadwork signs that say '82, slow down' and I look at my speedo and cant work out how 82 came up. Never knew if it was my car or the sign giving wonky data.
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It's perfectly normal.
Australian Design Rule 18 sets out the accuracy standards for vehicle speedos. Until July 2006 this rule specified an accuracy of +/- 10 percent of the vehicle’s true speed when the vehicle was travelling above 40km/h. That is, at a true vehicle speed of 100km/h the speedo could indicate between 90km/h and 110km/h. An odometer accuracy of +/- 4 percent was also a requirement.
From July 1 2006 a new standard began its phase in and by 1 July 2007 all new vehicles had to comply. The new standard requires that:
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.
Odometer accuracy is no longer defined.
What this means:
For a vehicle travelling at a true speed of 100km/h, the speedo must read between 100km/h and 114km/h. The effect of this is that you will find that at an indicated 100km/h you are driving up to 14km/h below the speed limit, as slow as 86km/hr with 100km/hr indicated on the vehicle’s speedo.
The speedo must always read 'safe', meaning the vehicle must not travel faster than the speed indicated by the speedo. So you don't need to worry about speed traps as you'll always be slower than what the needle says.
So long as you're actual speed is between 86 and 100 when your speedo indicates 100 its legal.
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10% +/- 4 km/h, to me at least seems a huge window.
Is it not possible to have the reading simply be accurate?
(hoping there is an engineer or someone on here who know for sure)
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The speedo is way out (it complies with the law). At indicated 120km/h you are doing 111km/h. I have tested this via a GPS.
You will also note that the cruise control speed is less than the analog speedo, at 115km/h set on cruise you are doing 120km/h on the analog speedo.
What is interesting is that if you activate the engineering mode digital speedo, you will find it is spot on. 111km/h on digital = 115km/h on cruise = 120km/h on the analog speedo.
I tend to drive with the digital speedo on all the time for this very reason. Know your margin and drive accordingly, do not attempt to "fix" it.
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I wonder if they do it on purpose to keep most people from speeding :bolt:
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I wonder if they do it on purpose to keep most people from speeding :bolt:
I agree
I also agree that its too big a 'window'. If you were on the limit of what the standard says, with 100 indicated but actually only doing 87 in a 100 zone, you'd be a hazard to those actually travelling at 100.
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but actually only doing 87 in a 100 zone , you'd be a hazard to those actually travelling at 100.
but no-one here drives a Camry, do they? :bolt:
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I found my 2017 was only about 3kmh out. But bought one of these as I wanted a big digital readout rather than analogue gauge (and couldn't be bothered setting up Engineering mode every time I started the car).
It plugs into the OBDII port and allows you to set an offset percentage to display. E.g 106% will display a value 6% higher than the computer is transmitting (be careful to check this with a GPS). I'm not sure it if will go to 110% though - which is what is needed if 100kmh on gauge is only 91kmh actual, so check with the seller first.
https://www.ebay.com.au/itm/P12-Car-HUD-Head-Up-Display-OBD2-OBDII-Fuel-Consumption-Speed-Warning-System-RPM-/263719199129?hash=item3d66e3a199&_uhb=1 (https://www.ebay.com.au/itm/P12-Car-HUD-Head-Up-Display-OBD2-OBDII-Fuel-Consumption-Speed-Warning-System-RPM-/263719199129?hash=item3d66e3a199&_uhb=1)
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I found my 2017 was only about 3kmh out. But bought one of these as I wanted a big digital readout rather than analogue gauge (and couldn't be bothered setting up Engineering mode every time I started the car).
It plugs into the OBDII port and allows you to set an offset percentage to display. E.g 106% will display a value 6% higher than the computer is transmitting (be careful to check this with a GPS). I'm not sure it if will go to 110% though - which is what is needed if 100kmh on gauge is only 91kmh actual, so check with the seller first.
https://www.ebay.com.au/itm/P12-Car-HUD-Head-Up-Display-OBD2-OBDII-Fuel-Consumption-Speed-Warning-System-RPM-/263719199129?hash=item3d66e3a199&_uhb=1 (https://www.ebay.com.au/itm/P12-Car-HUD-Head-Up-Display-OBD2-OBDII-Fuel-Consumption-Speed-Warning-System-RPM-/263719199129?hash=item3d66e3a199&_uhb=1)
I like this idea. Have always thought about doing a HUD. Can you please post a picture or 2 of what it looks like in the 2017?
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Can you please post a picture or 2 of what it looks like in the 2017?
Here are pics of the devices I have in my 2017 FB and my 1965 FB.
The 2017 has the device I linked above. I did check and it can have a speed adjustment ratio up to at least 120%. You can also set a fixed offset if say it is 2kmh off across the whole range.
The 1965 has a GPS HUD (amazingly no OBDII port in a 65!). Works very well, but is slower to respond to speed change, and can be compromised by bad weather limiting satellite access (more the better), or if you are driving through a tunnel. I like the HUD, but it looks ugly from the outside - especially on a 65.
You can get OBDII HUDs as well. Just search eBay.
https://imgur.com/a/nq0G6Uc (https://imgur.com/a/nq0G6Uc)
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:grin: :grin: :grin: :grin: :grin:
but no-one here drives a Camry, do they? :bolt:
:grin: :grin: :grin: :grin: :grin:
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My 2017 GT reads about 3 kph slower than actual. I have gone past many police in the highway doing about 107 on 100 zone and 118 in a 110 zone and never been pulled up / fined.