My speedometer (needle) is about 10% high. Is there a calibration that can be done without opening it up?

I converted my car from tiptronic to manual. I actually converted two cars, swapping the transmissions and all associated equipment. The speedometers had to go with their respective transmission due to the tip gear selection indicator. Both speedometers were sent to Palo Alto speedometer to have the odometer readings set to match the respective cars and to change the bezels (one an S, the other non-S). They called and recommended changing the gear mechanism in both, said the gears get brittle with age. They had the speedos open anyway so the only additional charge was for the new gears.

The trans swaps took months. When it was completed I didn't drive it much for a few more months due to our Utah winter weather. As I got some seat time it seemed very fast ... but it didn't feel right or seem right relative to other traffic. After I replaced a bulb so I could see the onboard computer display on the tach, it showed speed about 10% lower than the needle. A phone app agrees within 1 mph with the digital display. The roadside speed warning signs agree with the phone app and the digital display.

The tiptronic speedo has a different PN from the manual that I assumed was due to the gear indicator. Do you know if the needle drive ratio is different from the manual? If there's an adjustment I can do that would be the best solution. If not I'll send it back to Palo Alto Speedometer for calibration/repair.

The car accelerates much quicker with the manual. And it is great to have 4 useable gears on the track (as opposed to two that never seem to be in the right range with the tip). I love it!

 

I sent email to PA Speedo and Hartmut called me right away. He said that the calibration is internal. They calibrate to factory specifications on the speedometer housing. Harmut said to give him accurate needle readings at 30 mph and 60 mph and they will calibrate to that.

 

Good info, thanks. I've used those guys before and they really seem to know what they are doing.

 

Okay, so tell the truth. Last fall at Miller you told me you were hitting 130 mph on the main straight. Was that with or without compensation for the inaccurate speedo?

 

That's from the digital display. I wouldn't say it's accurate to the mile per hour at that speed but should be much closer than the needle (and quicker to locate/read). At the end of the front straight of the full track is the only place I will look at the speed. If there are no other cars around I'll peek at the digital indicator right at the brake point. You know ... to see how consistent I am through the last turns. I'd like to install a video/data system but there are a lot of things on my want list.

It's about +4 mph over the tiptronic at that spot.

 

Hi
My digital speedo is inaccurate by 5 klms at 60 Klms, is there any way the digital speedo can be calibrated?

Neil

 

NHS is the place to go.

 

A deviation of 5 to 8% at 60 to 100 km/h is normal. These instruments are adjusted like this in order to allow for different wheel circumferences and other measurement deviation.
This is normally focused on the 50-100km/h speed region, as the deviation is non-linear across the dial. It is of course possible to calibrate them spot on, but I most often adjust them as they were from the factory.
Cheers,
Tore

 

I would definitely send your speedometer to PAS as Harmut is such a professional. Consider sending him all the gauges if you have any interest in refurbishing them.

 

How much $$ did they want for the recalibration?

mine is off too…