Speedo Calibration...???
 

I have a 2000 Land Rover Discovery II running 33's on factory gears.... I recently got a ticket for a bogus speed, and I tried contacting a shop that has calibrated a 4Runner that I used to have... Problem is they don't know if anything even exist for this vehicle to do the calibration, and ultimately they can't even put my truck on their dyno because it is only a two wheel dyno... So short story long, I called Sierra Expeditions in Tempe, AZ, and they are trying to find a part that he says a few people make but, he's not sure which was the best one to the do the job... I guess this part goes between the sending unit and main unit, and once connected I calibrate it by running a gps through a given distance... So my question is if any one on the forum have had any success on the re calibration of a speedo on these trucks...???

I always just used my gps untill I got a feel for my actual speed in relation to my gauge.

however if you want to do it the hard way, cant you just unhook one drive shaft and put the truck on a dyno?

Sounds a lot easier and cheaper. You're not measuring hp, just speed.

X3 That's basically what RAVE says to do: Engage CDL, remove drive shaft, put on rollers.

yah thats right, I've read that before, only didn't cross my mind when he was telling me that he couldn't do it... so only problem is I have yet to install the linkage to the cdl... so I could just tell him to actuate the cdl with a wrench though right..?? I've never actually engaged it but I know it has cdl....

so the idea is if cdl is not engaged then all the power will be sent to the disconected shaft... right...?? I'm sure they should be able to grasp this concept... Only still don't know if there is anything on the market that will be able to allow us to even make the calibration possible... the place is called Dicks speed o n tach, I know this is their specialty, and not many other options for places to use here in Phx, but he said he's never done a disco.... So thats why also I was wondering if any one has ever even done this....????

Exactly. If it is a 2000, and has the original transfer case, it WILL have CDL, you just need to turn the lever with a 10mm open end wrench.

Exactly.

This is the only thing I am not certain about. I know companies make adapters for vehicles that use a speedometer cable (I had one when I went from 185/70/13 tires to 245/45/16 tires on my 1984 RX-7), but I don't know about electronically controlled speedometers.

I've never heard of anyone using this, but I don't see why it wouldn't work.

TruSpeed™ Speed Sensor Recalibrator · Superlift · www.superlift.com

Now, for someone to reverse engineer it to be compatible with Landys... ;)

From what I have read and have been told by indie and non indie mechanics, there really is no way to adjust the speedo accurately enough for the time and energy put in... they all suggest the same thing.. GPS at 30, 40, 55, 65. have someone with you who can read the GPS when you tell them you are at the set speed on the trucks speedo... use this as a general % for you, if need be print it out and place it on the dash or somewhere you can see it until you remember.... I know with my 03 with the 265/75/16's the speed difference is at 10.3%(roughly) so at 60 mph on the truck speedo I am between 66-67 mph.. si on highway I cruise control it at around 63 on the speedo and watch the world go by at the same rate as my gas gauge drops....

I use an UltraGage and calibrated that using a GPS. It works well and I set it up to show Engine Coolant Temp and MPH in the largest display. I have 32s which only put my speedo off by about 6mph at 55 but it's nice to know actual speed.