GPS Speedometer

[roscoe]

Over the last couple of years I added a Toyota 5-speed gearbox, and a 3.54:I ring and pinion set to my differential. On top of that I run non-standard tires. As a result, my speedometer doesn't register anything near to an accurate speed. I have been meaning to take the simple measurement of counting the number of revolutions my speedometer cable turns over a set distance that is some fraction of a mile, and then send the speedometer to one of the usual suspects to have it re-geared to correct for this. However, I found it easier and probably about the same cost to install a GPS-driven speedometer which I have just completed.

I have no bias for this company. I chose a Speedhut unit and so far I am very pleased. I shopped around looking for something that looked as much like the Smiths gage as I could find. I did not want one of the various units out there that drive off the speedometer cable which goes into a converter box which you can calibrate to your needs. Finding one that was self contained, save for the small antenna, was not going well until I found Speedhut. Lots of cheap units out there that might look fine in a ski boat but not so much in the Healey. I selected the features that most resembled the origional.

I did not select built-in turn signal indicators or a high beams LED, but they are offered. Simple 3 wire install, ignition power, lighting circuit power and ground. The antenna works fine situated on the dash behind the steering wheel. The small digital display offers lots of features I probably won't ever use. Their customer service seems very good and it is built in the US. It took less than 2 weeks to get my bespoke ( I've always wanted to use that word) speedometer. Aside from the bezel being a satin finish rather than chrome and being a little fatter, I think it looks acceptable.

 

[Michael Oritt]

Roscoe--

I've made the same mods to my 100 and though I have thus far relied upon an inline conversion box to give more or less accurate speed indications I have thought about replacing both tach and speedo with electronic units.

I've looked at the set that Moss offers which do seem to be a nice match for original. Their speedo does not run off GPS but rather a speedo sensor kit where a sender is fixed to some revolving member such as a wheel, prop shaft, etc.

When you decided to buy the Speedhut unit were you familiar with this option and if so what drove your selection?

 

[roscoe]

Michael,
Several things made my decision. First, it was just a tad over $300. The ones I saw that used Hall effect sensors were comparable until I saw that most did not include the sensor unit which ran up the price. I also wasn't looking forward to making a bracket or figuring out how to mount the sensor. I've had Hall effect sensors fail on me over the years so as far as I was concerned, fewer parts, the better. I don't care if I lose my speedometer for a few moments in a tunnel or if it takes up to 40 seconds to acquire satellites. I had about given up reading reviews of more inexpensive units that failed and were from places far over my horizion where customer service could be an issue. I have to say that Speedhut has the kind of customer service that made me smile. Prompt emal responses and order follow up. I liked that they had the selection of diameter size that gave me a perfect fit. Many of the round units for sale are not the 100mm needed. Picking out features like needle and center button style, back light color, face fonts and bezel style were what finalized my choice.

Not that I'm a track guy but it also has a 0 to 60mph automatic timer, a 1/4 mile timer, altitude, compass, trip odometer and peak speed functions. If I cared, my only complaint would be that in bright sunlight the small digital display can't be read. At night or with some shade it'd be fine. I have asked them about that this morning and await a response. I didn't ask and dont really care if they can be pre set to show carried over total mileage so if that is important to someone it bears asking.

It does make a slight whirring noise when it boots up and it sounded to me like a small electrical wire arcing and made me start sniffing around and reaching for my fire bottle on the glove shelf, until I realized what it was.

 

[Michael Oritt]

Jon--

Thanks for your reply and I understand your considerations.

The Smith's units that Moss sells offer a couple of features I find attractive: First, the heads appear to be the same size as the originals and thus easy to fit, plus I believe they match the "style" of the original units and have modern lighting built into them.

I too have a Toyota box and I have no reason to believe that the electrical sender for a speedo signal would not work if renewed, And my Mallory distributor/coil setup should make getting good rpm info to the tach a cinch.

On the negative side, the ranges of both units (0 to 140 mph and 0 to 7000 rpm's) far exceed the capabilities of the car and will result in somewhat compressed scales, but I can tell anyone who asks that my car is especially fast!

I'm in the process of installing a new clutch and once I finish with that I'll make a decision bu thanks for your insight and experience.

 

[twas_brillig]

Have a look at > GPS Speedometer <
I've got two entries in there, regards using magnets to mount a Garmin GPS unit to the heater box of our BJ7 so as to get accurate speed (we have the Toyota 5 speed and a 3.91 diff vs. the gearing for a 3.54 , plus I'm not convinced of the condition of our stock speedo. No quarter mile times, and the sun angle can mess up readability, but only a hundred or so bucks and easy to do. And I'm keen on both cheap and easy.... Doug

 

[John Turney]

Have a look at > GPS Speedometer <
I've got two entries in there, regards using magnets to mount a Garmin GPS unit to the heater box of our BJ7 so as to get accurate speed (we have the Toyota 5 speed and a 3.91 diff vs. the gearing for a 3.54 , plus I'm not convinced of the condition of our stock speedo. No quarter mile times, and the sun angle can mess up readability, but only a hundred or so bucks and easy to do. And I'm keen on both cheap and easy.... Doug

If you want cheap and easy, I use the free GPS Odometer app on my iPhone. 3,000 RPM in 4OD = 66 MPH.

 

[roscoe]

I used my phone for a bit but missed being able to look at the speedometer which I feel you can do without loosing sight of the road ahead. I have several handnheld GPS units and didn't like using any of them if I was driving. I also like having an odometer with trip function that is accurate which was way off once the mods were installed.

I started the thread about GPS speedometers Twas-brillig mentioned and now recall that was where I got clued in to Speedhut. This was my followup/ solution.

I did hear back from their customer service and although they have no brightness adjustment on their gage, she said they are intending to do that but don't know when it will be incorporated. It would be worth the extra cost in my book.