Speedometer Calibration?

[tyb323]

Hey guys. I have a 160 mph speedometer (overkill, I know, it was a P.O's purchase) Anyhow, it is reading about 7-8 mph too slow. Is there a way to calibrate these speedometers?

[ssdelorean]

If you can find a speedometer shop it is really easy. They hook it up to a machine, spin it up to speed and adjust the magnets with a screw driver. I had mine done by Bob's (http://www.bobsspeedometer.com) in Michigan when I converted over to a 140 speedo. Literally took them 3 minutes. I spent more time BS'n with the owner about all the old gauges he had on display then it took for him to re-calibrate.

If you are having trouble finding a place just give Bob's a call and they can tell you what questions to ask when looking. I'm sure you could even ship it there have them adjust and ship back if in a pinch.

[David T]

You have to send the speedometer head to a shop for calibration. Or you can just make up a deviation card with the known correction factors at each speed.
David Teitelbaum

[Lenny]

Call your local PD. they have to get their speedometers calibrated. Ask them where they have it done.

Lenny

[Helirich]

Reviving a very old thread.

I would like a 140 mph speedo. DMC sells them for 5 hundred bucks. I might pay that, but I would like to explore other possibilities. I see on the Deloreango site, they sell a 240 kph speedo "sticker". My question, if you get that sticker (or another in mph) can you calibrate a 85 mph up that high? Or is there a range it can be calibrated, after which you need to get a differnt guage?

[David T]

You get the new sticker and then have your speedo head recalibrated. Essentially what is done is that they spin the speedo at 60 RPM's and adjust the spring to read 60 MPH. Any good speed o shop can do this, Bob's is one of them. I recently used them for another car (not a Delorean) and I found them to be slow and pricey.

[Josh]

If you have a speedbox you can recalibrate on your own, and not worry about angle drives.

Also, IMO these 140mph / speedos are a bit much for this car. Your usable range is much smaller.

[Helirich]

If you have a speedbox you can recalibrate on your own, and not worry about angle drives.

Also, IMO these 140mph / speedos are a bit much for this car. Your usable range is much smaller.

I've considered the speed box, seems kind of more complication. I guess it's more reliable. It's funny how my 50 year old VW has cable drive off the wheel that still works. (I need to look at how it is driven)

I said 140 because that's what they sell. 120 is probably better for a stock Delorean.

That brings me to a question for you Josh. Have you done anything to yours with 500 plus hp? I imagine 180 or more is in order. How fast have you had it up to? Does your gearing allow for 200 mph? I suppose the front suspension could be trouble at that speed. I know the Corvette has a strange set up I believe in the "Ackerman angle". It's supposed to make it more stable at high speed, but it makes terrible noise at parking lot speed when turning hard. It sounds like a locked differential.

[Josh]

It does not matter how much power you have, a delorean should not be driven faster than 130mph imo.
Especially with the stock wheels and tires nothing is available over a 112 mph rating.

[David T]

There was a guy from Staten Island, NY that raced Deloreans and he said once he got to around 120 the front started to lift. Aerodynamically the air under the car made the front lighter and leads to a loss of steering control. Besides, as pointed out, the speed rating on the tires will be exceeded. For sustained high speed driving you should increase the tire pressure to prevent bead roll over too.

[ssdelorean]

There was a guy from Staten Island, NY that raced Deloreans and he said once he got to around 120 the front started to lift. Aerodynamically the air under the car made the front lighter and leads to a loss of steering control. Besides, as pointed out, the speed rating on the tires will be exceeded. For sustained high speed driving you should increase the tire pressure to prevent bead roll over too.

A while back I was chasing a vette going 123mph. I felt no front end lift. FYI my car is lowered 1.5" in the front and not "stock" nose high. When my car was stock nose high I felt a float on the road going over just 65mph.