04 A8L speedometer
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Joined: Jul 2003
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04 A8L speedometer
My car, serial 8170 was picked up last week. (Night blue/amaretto) I have 400 miles so far and no problems. I did a speedometer check on the interstate today and as others have been saying, the speedometer is about 5 miles per hour fast. ( I have 18" wheels) I set the cruise at 60, 65, 70, 75, and 80 and time with a stopwatch the time to go one mile by the mileage markers. Then take 3600 and divide by the number of seconds to go one mile and you get your speed. For instance today at cruise setting of 80 it took 48 seconds to go one mile. 3600/48= 75 MPH. It took 52 seconds to go one mile at cruise set at 75. 3600/52= 69.2 MPH. The speedometer is about 5 miles per hour conservative. You should do this on a level stretch of freeway. On my airplane the GPS gives your groundspeed--I wonder if our GPS on the A8L could ever give your speed??
Audiworld Junior Member
Joined: Aug 2003
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Compare the speedo with the trip computer
I did the same comparison on my Tour o'Desert last week; the error seems to be about 5% (not a constant 5 mph). You can see it easily by setting the cruise control at a clear speed on the speedometer (e.g., 70 mph). Then go to one of the average speed readings on the trip computer and reset that. After it flashes to zero, the correct speed will come up (e.g., 67 mph in this example). I confirmed that the trip computer was seeing the correct speed using the stopwatch approach. Why the trip computer knows about the different tire/wheel size (which is the cause of the error) but the speedometer does not is beyond me. I would have expected both devices to get the same signal.
AudiWorld Senior Member
Joined: Jan 2001
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From: Austin, TX
May be due to German laws ...
In Germany, the Speedo has to show the correct speed no matter what size wheel you put on the car. So technically, the A8 needs to show the correct speed if you use 15" or 20".
I know that a lot of German car magazines show speedo speed and actual speed comparisons and they ALWAYS have a difference (actual speed lower than speed displayed).
I would assume that there is nothing actually wrong with your car(s), it's designed that way.
2000 A8L
I know that a lot of German car magazines show speedo speed and actual speed comparisons and they ALWAYS have a difference (actual speed lower than speed displayed).
I would assume that there is nothing actually wrong with your car(s), it's designed that way.
2000 A8L
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Joined: Jul 2001
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From: Wilbur by the Sea
The trip computer gets real speed, the speedo gets a slower speed
That's because of laws that state it can't display lower than actual speed. Obviously Audi has the K factory set too high!
I wonder if there is a "K" factor measuring block that can be changed in the instruments to make it more accurate. Wouldn't surprise me.
pw
I wonder if there is a "K" factor measuring block that can be changed in the instruments to make it more accurate. Wouldn't surprise me.
pw
Banned
Joined: Sep 2000
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VAG-COM Trick
Paul,
On your car you can do the Output Test on the instrument cluster. When get to the speedomter, after swinging the needle through it's extreme, the cluster will produce and hold simulated 100 km/h (62.1 mph)signal. Now you can see how much the needle is off. Same for the tach, but the simulated signal is 3000 rpm.
No, you can't do this with an 04 yet. But I have an appointment with a dealer to "test drive" an 04 on Friday. Yes, they know my concept of a test drive involves two laptops, a VAS-5052, but no actual driving.
We hope to have a new version of VAG-COM that fully supports the new '04 and an new dual-K + CAN interface ready in January. In the meanwhile, we're looking for Alpha testers. If anyone with an '04 is interested, please e-mail me. Perference will be given to someone in the Philly area who would be willing to stop with their car on occasion.
-Uwe-
On your car you can do the Output Test on the instrument cluster. When get to the speedomter, after swinging the needle through it's extreme, the cluster will produce and hold simulated 100 km/h (62.1 mph)signal. Now you can see how much the needle is off. Same for the tach, but the simulated signal is 3000 rpm.
No, you can't do this with an 04 yet. But I have an appointment with a dealer to "test drive" an 04 on Friday. Yes, they know my concept of a test drive involves two laptops, a VAS-5052, but no actual driving.
We hope to have a new version of VAG-COM that fully supports the new '04 and an new dual-K + CAN interface ready in January. In the meanwhile, we're looking for Alpha testers. If anyone with an '04 is interested, please e-mail me. Perference will be given to someone in the Philly area who would be willing to stop with their car on occasion.
-Uwe-
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