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I think it does, but I have not confirmed this to be true.
Locally we have a few marked lengths of highway for airborne speed patrol - the marks are at 500m intervals over a 2.5km stretch.
Our Cayenne, 911, and 330i (2004 ZHP) all calibrate to 3-5% more distance on the odo than (presumably accurate) hwy markings. This fits precisely with the speedo error.
IIRC, the N American regs specify speedometers can show speeds faster than true, but not slower than true.
(The latter would allow you to get away with a ticket by claiming your speedo said you were doing 60 when the cops clocked you at 60+).
Most Euro manufacturers tend to calibrate speedo a little "fast" for this reason (at least all my Euro cars over past 45 years).
Interestingly, the Cayenne is the most accurate, but only on summer tires - it slips into the 5-ish% fast on winter tires (and yes, I do change the display to the appropriate tire choice).
Oh, been meaning to look into the proper software for Porsche diagnostics. I have ISTA+ and VAGCOM running on a windows 7 virtual machine on mac air. Both work fine. I could not get VAGCOM working on Windows 11 on my new MacBook although others have reported it works on M1 chip Macs...>I have to figure that out.
Anyway, do you now if PIWIS supports VM's on macs???
Mike
It does work on Intel chipset. No go on M1 and VMware Workstation Pro 17 installing Windows 10. I haven't tried installing Windows 11
@Z06jerry I've solved my problem. My Kodierwert Laendervariante Tacholinie is set to ROW (ie, RDW), so I've set the following:
Example, I change y4 from 105 to 100. The speedo now reads a touch less than Google. Example, a speedo 100kmh varies between 100 and 101 on google. This means my speed was about 4.5 - 5 % fast
I got curious after this thread. I know they are not dead ***** accurate but I wanted to see. So I finally took ten minutes to check my Speedometer vs GPS with XGPS160 unit. Both my Boxster and M5 were within 1 mile per hour at 75 mph. I'm good with that.
I got curious after this thread. I know they are not dead ***** accurate but I wanted to see. So I finally took ten minutes to check my Speedometer vs GPS with XGPS160 unit. Both my Boxster and M5 were within 1 mile per hour at 75 mph. I'm good with that.
Mike
Perhaps you set to USA rather than ROW. I had tried this before the changes I described, and it was within 2%
@Z06jerry I've solved my problem. My Kodierwert Laendervariante Tacholinie is set to ROW (ie, RDW), so I've set the following:
Example, I change y4 from 105 to 100. The speedo now reads a touch less than Google. Example, a speedo 100kmh varies between 100 and 101 on google. This means my speed was about 4.5 - 5 % fast
I'll have to devise an odometer test
@LP718 Good to know, I'll give that a try soon too.
@Z06jerry I've solved my problem. My Kodierwert Laendervariante Tacholinie is set to ROW (ie, RDW), so I've set the following:
Example, I change y4 from 105 to 100. The speedo now reads a touch less than Google. Example, a speedo 100kmh varies between 100 and 101 on google. This means my speed was about 4.5 - 5 % fast
I'll have to devise an odometer test
To remove even this small error, I'm going to try setting 100 to 100.5kmh. Has anyone ever tried inputting decimal numbers?
03-26-2023, 03:17 PM
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