Speedometer accuracy, spot on. - Page 2

Jake · 06-03-2008, 08:28 PM

My new 08 STi speedo reads ~5kph higher than the speed shown on cars GPS. This has also been confirmed with a second portable GPS. Form this thread, it seems to be a common problem.

Is there some way to calibrate the speedo? I would have thought it would be possible to allow for different tyre sizes etc?

My problem is that I paid good money for a car that can't make an accurate speed measurement. Seems very odd for a car that is crammed with technology.

Apart from that the car is great.

**Digitalfiend** · 06-03-2008, 08:35 PM

Quote:

Originally Posted by Jake

My new 08 STi speedo reads ~5kph higher than the speed shown on cars GPS. This has also been confirmed with a second portable GPS. Form this thread, it seems to be a common problem.

Is there some way to calibrate the speedo? I would have thought it would be possible to allow for different tyre sizes etc?

My problem is that I paid good money for a car that can't make an accurate speed measurement. Seems very odd for a car that is crammed with technology.

Apart from that the car is great.

Are you sure? I've done some datalogging and the gauge is spot on with the ECU. I've also passed a radar station and the speedo was spot on. I haven't looked at the GPS info in the NAV unit.

Are you running stock tires/wheels?

Bishop · 06-03-2008, 08:43 PM

i havent read any posts other than the 1st, but thought i'd chime in, on how bad my 07 is

registers 4mph fast, so 50 = 46 according to my TomTom and various radar billoards around town

Jake · 06-03-2008, 08:59 PM

Running stock tyres on stock 18" rims - Dunlop 245/40R18.

I do notice that the stock STi rim size in the UK (for instance) is 17" . This would account for the speedo error which is why I questioned whether there is some calibration 'switch' to account for this.

jrdriller · 06-03-2008, 09:10 PM

up to 5% error permited by federal regulation

Speedometer - Wikipedia, the free encyclopedia

Jake · 06-03-2008, 09:21 PM

Yep read that - in Australia it is up to ±10%. Hope the speed cameras allow for this!

However, the question still remains - is there an adjustment to calibrate?

Blueraven · 06-03-2008, 11:49 PM

Mine reads 8-9% too high.

meaning when i am doing an indicated 100kph i am actually doing more like 92. to keep up with traffic on a freeway here with a posted limit of 100 i find myself doing an indicated 109.....

kinda bothers me, will get it corrected/adjust on its first service.

jrdriller · 06-04-2008, 08:01 AM

Quote:

Originally Posted by Jake

Yep read that - in Australia it is up to ±10%. Hope the speed cameras allow for this!

However, the question still remains - is there an adjustment to calibrate?

no electronic calibration otherwise it would be too easy for people calibrate it to show fewer miles on the odometer.

make sure that your tires are inflated to the recommended cold tire pressure (taking into account ambient temperature when you adjust the pressure) if that doesn'r get you close and you asume that GPS is correct, change tire pressures until you get what you want

supermarkus · 06-04-2008, 12:08 PM

mine is dead on when compared to my Nuvi 350

mikeygar · 06-04-2008, 12:23 PM

tested my 08 STI at 240 kph on the cluster. My handheld Magellan GPS showed 224 kph...

jonny427 · 06-04-2008, 12:28 PM

Quote:

Originally Posted by Iguana

I'm glad that my speedo reads high. That way, I'm less likely to be actually speeding.

+1

06-03-2008, 08:28 PM	#16
Jake Lurker Car: White 08 WRX STi Fav Mod: Coming Soon Posts: 3 Join Date: Jun 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. My new 08 STi speedo reads ~5kph higher than the speed shown on cars GPS. This has also been confirmed with a second portable GPS. Form this thread, it seems to be a common problem. Is there some way to calibrate the speedo? I would have thought it would be possible to allow for different tyre sizes etc? My problem is that I paid good money for a car that can't make an accurate speed measurement. Seems very odd for a car that is crammed with technology. Apart from that the car is great. This ad is not endorsed by this member. Please register or login to hide this ad.

06-03-2008, 08:43 PM	#18
Bishop HowTo Contributor Car: 07 OBP STi Fav Mod: Stg 2 - STRI gauges Location: Niwot, CO Posts: 2,321 Join Date: Oct 2007 Trader Rating: (0)	Re: Speedometer accuracy, spot on. i havent read any posts other than the 1st, but thought i'd chime in, on how bad my 07 is registers 4mph fast, so 50 = 46 according to my TomTom and various radar billoards around town

06-03-2008, 08:59 PM	#19
Jake Lurker Car: White 08 WRX STi Fav Mod: Coming Soon Posts: 3 Join Date: Jun 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. Running stock tyres on stock 18" rims - Dunlop 245/40R18. I do notice that the stock STi rim size in the UK (for instance) is 17" . This would account for the speedo error which is why I questioned whether there is some calibration 'switch' to account for this.

06-03-2008, 09:10 PM	#20
jrdriller Junior STI Driver Car: Silver 08 STI Fav Mod: Coming Soon Location: Houston Posts: 189 Join Date: Apr 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. up to 5% error permited by federal regulation Speedometer - Wikipedia, the free encyclopedia

06-03-2008, 09:21 PM	#21
Jake Lurker Car: White 08 WRX STi Fav Mod: Coming Soon Posts: 3 Join Date: Jun 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. Yep read that - in Australia it is up to ±10%. Hope the speed cameras allow for this! However, the question still remains - is there an adjustment to calibrate?

06-03-2008, 11:49 PM	#22
Blueraven Junior STI Driver Fav Mod: Coming Soon Posts: 51 Join Date: Apr 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. Mine reads 8-9% too high. meaning when i am doing an indicated 100kph i am actually doing more like 92. to keep up with traffic on a freeway here with a posted limit of 100 i find myself doing an indicated 109..... kinda bothers me, will get it corrected/adjust on its first service.

06-04-2008, 12:08 PM	#24
supermarkus Spec C Club Car: 08 STi, SSM Location: Edmonds Washington Posts: 1,441 Join Date: Dec 2005 Trader Rating: (0)	Re: Speedometer accuracy, spot on. mine is dead on when compared to my Nuvi 350

06-04-2008, 12:23 PM	#25
mikeygar Amateur STI Driver Car: White 08 STi Fav Mod: Coming Soon Location: Philippines Posts: 25 Join Date: Apr 2008 Trader Rating: (0)	Re: Speedometer accuracy, spot on. tested my 08 STI at 240 kph on the cluster. My handheld Magellan GPS showed 224 kph...