GPS Speedometer

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Gene Gillam
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Location: Saucier, MS

GPS Speedometer

Post by Gene Gillam » Sun Apr 28, 2024 5:20 am

Has anyone adapted a GPS speedometer to a T-series? I have a TC with a 5-speed and a 4.85 differential and rather than contact Speedograph for an adapter (expensive) wonder if anyone has printed a face to match the T-series face for a GPS type? If so, which speedometer and would you be willing to print one for me?

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Franz Tenbrock
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Location: Waltrop Germany

Re: GPS Speedometer

Post by Franz Tenbrock » Mon Apr 29, 2024 10:38 am

here was a discussion about it
now you can get a analoge gps tacho 52mm too

my ampermeter is without function, don t want such thick wires behind my dashboard
so i could use this place for a 52mm gps
off course with a Mg TA like face

but
i would prefere something like this
https://german.alibaba.com/product-deta ... 59242.html

with smart functions
navigation
water temp
oil pressure
and
speed.

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Duncan M
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Location: Northern California

Re: GPS Speedometer

Post by Duncan M » Tue Apr 30, 2024 9:58 am

Franz-
Two different "heavy" (12 gauge) wires are behind the dash. They are essential to the operation
of the car. See page 3 of this article-- http://www.tcmotoringguild.org/techinfo/TClinic-25.pdf

Cable #9 is 12ga (41 inch long) wire from Ignition switch to regulator <>

Cable #33 is 12ga (75 inch long) wire from ammeter to starter <>

Using thinner gauge wire to the ignition switch or starter will result in hot wires and electrical failures.

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Franz Tenbrock
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Location: Waltrop Germany

Re: GPS Speedometer

Post by Franz Tenbrock » Tue Apr 30, 2024 9:09 pm

Hi
you are normaly right
but,
my car has 6 relays in the position of the regulator box,
my genrerator is a morden one with regulator inside,
no heavy wires behind the dashboard.
handmade lwiring harness

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cdrolshagen
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Joined: Tue Dec 29, 2015 1:30 am
Location: Soerup Germany

Re: GPS Speedometer

Post by cdrolshagen » Tue Apr 30, 2024 11:29 pm

Hi,
my TC and also the J2, the only relay that is installed is the flasher relay and that is also electronic because I use LED light bulbs for the flasher, the ignition system is also converted to electronic, otherwise the vehicles are completely analog,
I don't understand what this electronic nonsense has to do with a classic car.

cheers and have a nice day with bits and bites,
Carl

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Duncan M
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Location: Northern California

Re: GPS Speedometer

Post by Duncan M » Wed May 01, 2024 8:02 am

I have a wiring harness I made myself using all the original type bullet and other connections at the original locations with orignal gauge wires. Original dynamo, original regulator and chronometric instruments, etc. 10 years and zero troubles with the wiring. Not a single problem, ever.

I think Gene is looking for info on using a GPS speedometer, mounted in the dash, as his chronometric speedo is off by quite a bit due to his special setup. Only problem I could see is maybe an issue with ignition noise from an original ignition setup. Maybe not a problem. I have had passengers tell me how fast the TC was going by some app on their iphone's. We have some radar trailers in the area that show your exact speed, and between the radar and iphone info, the chronometric in the TC is within 2 mph at 50mph running slightly oversized (outside diameter) 475/500-19 tires. It is spot on accurate in the 25-30mph range. My chronometric does not bounce, it just does the notch increments like it should do.

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Ian R
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Joined: Thu Aug 19, 2021 4:40 am
Location: Leesport, PA, USA

Re: GPS Speedometer

Post by Ian R » Wed May 01, 2024 2:54 pm

I went in another direction in that I purchased a cheap Digital GPS speedometer from amazon.

On my TA, the speedometer is in front of the passenger so it is not real easy to read anyway.
So I fixed a small GPS display on the top of the dash behind the windscreen & it is easily read & accurate whatever diff & tires are fitted.
I wired it to a USB outlet that I had already installed under the center of the dash (to allow for cell phone charging).

For Shows etc, I just remove it. Takes 10secs at the most.

Link is: https://www.amazon.com/gp/product/B07FNHGRZ9

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Ray White
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Re: GPS Speedometer

Post by Ray White » Thu May 02, 2024 5:35 am

As it happens I fitted my speedometer only yesterday. I had the original instruments rebuilt by John Marks of Vintage Restorations. John owns the British Jaeger brand and was able to print it onto the other gauges (petrol, water and supercharger boost/vacuum) that I have added.

I imagine he has retired by now but what he did was to re calibrate the TC speedo to allow for TA gearing combined with a five speed gearbox. This negates the need for an add on gearbox.

I had to make a new dashboard anyway so I decided to switch the position of the speedo with the tachometer because these days watching your speed is more important than worrying about revs. I could only do this because the new gearbox had such a long speedo cable.

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