wondering how many of us are using gps speedos
 

I was just wondering how many cobras are running gps speedos or what the pos & negs of doing so
as I still have to calibrate mine or do I just go gps run as they say gps are true klm;s but just one down side of tunnels
please help
rob **)**)**)

The main negative is that they're non compliant to ADRs.

Treeve

On level roads GPS is quite accurate if your unit is getting a good satellite signal. I trust mine nearly to the km and it hasn't failed me yet. One thing I do is establish the inaccuracy of the standard speedo so that even without the GPS I'm aware of the margins of error. I know that 120kmh indicated on my road car is slightly less and therefore safe, hasn't failed me yet.

GPS speeds on hills are another matter as they can be inaccurate due to the lack of barometric data. Generally a GPS is only designed to measure distance vs time which when applied horizontally is fine. On a hill the GPS will continue to measure speed horizontally and ignore any vertical change of position. Therefore the GPS will indicate a slower speed on hills than the car is actually travelling.

I'd stick with a standard electronic speedo and use a GPS to calibrate it on a straight and level road.

I installed the Speedhut GPS speedo and have a little over 7k miles on it now.
I REALLY like it.

I don't see the tunnels / hills as really being a downside. I agree with the facts, but tunnels aren't typically that long that it matters and I would think the hill difference is not significant.
Super easy to install and no calibration issues. The Speedhuts are also customizable and led lit.

what is your concern?

As Treeve states, GPS speedo's are non compliant in Australia.

so I see that gps speedos are not compliant
so does any one know what pulses are put out per klm for an lsi with a4l60e so I can program mine
or does anyone have a good solution to program a vdo electronic gauge
thanks rob

Rob the speedo PPM from the ECU is based on the number of revolutions that your gearbox output shaft is putting out, final calculation depends on diff ratio and tyre size. The speedo should have instructions on how to calibrate it; for some you drive at a known speed (either with GPS on a phone for example, or by driving next to another car travelling at a set speed), or some need you to drive a certain known distance while in calibration mode.

RTFM

To program a VDO speedo (using the KM markers on the side if the road)
To use the auto calibrate mode:

1. Press the button on the front of the speedometer, hold it in, and start the engine. Release the button when the display reads, "AUTOCL"

2. After three seconds, the word "BUTTON" will show on the display. When you are ready to begin your calibration run, press the button again. The display will now begin flashing the word "START."

3. Drive the reference distance of one KM. NOTE: As you drive this distance, the speedometer needle will not register or move. This is a normal occurrence during the auto calibration process.

4. When you have gone exactly one kilometre, press the button again. If the electronic impulse rate detected by the speedometer's microprocessor is within the calibration range limits of 500 to 399,999, the rate will be shown on the LCD display. For example, your reading might be "P16000 ^ Calibration Range 16000). Such a display indicates that the impulse rate detected during the reference mile you drove exactly matches the microprocessor's programmed rate for 1 kilometre. That means the speedometer is now perfectly calibrated to provide the most accurate display possible of both speed and distance. The speedometer finishes its Auto calibration by moving the pointer through a full sweep, then back down to zero.

However, if the speedometer detects any kind of error during your run, the LCD will display the following, "P00". This means no useable impulse was detected. In this case, simply turn off the ignition, and start the process again.

REMEMBER: During the autocalibration run, the pointer on the speedometer will not operate.

well this might have to wait till Friday craig as its pits day Friday then ill see if they have a 1km marking & do it with them also I read the program booklet & it asks for ether 1km or pulse
so looks like 1km will be easier for me

Borrow a gps and use its odometer on a flat straight road. Easy as :)

well guys the di--head factor has hit again
I was reading the wiring plans [trying to read other languages ] as mine didn't come with English in the box
found on line that I had connected no8 & 6 bridged as I said [ sort of ] & found out I was wrong again connect to no.8 only for gm motors
so now I have speedo for Friday counting the days now
thanks for all
rob

Zero dollar fixes are always the best fixes.
Good luck for Friday. Take lots of pictures and videos please!

craig how do you do it [remember carpenter not tech