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Technical GPS speedometer

Discussion in 'Traditional Hot Rods' started by Jim Hewitt, May 2, 2022.

  1. Blues4U
    Joined: Oct 1, 2015
    Posts: 8,057

    Blues4U
    Member
    from So Cal

    I have an old Garmin GPS stuck on the windshield of my 30 pickup, it's been there so long I think the rubber suction cup is permanently adhered to the glass, I'd probably have to scrap it off with a razor blade to remove it now. I hard wired the power cable in to the ignition switch so it comes on whenever I turn the car on, and automatically turns off when I switch the engine off. That's my speedometer, and odometer, when I hit 100 miles on the Trip mileage I start looking for gas; and reset it each time I fill up. Occasionally I still even use it for directions...
     
    Last edited: May 6, 2022
  2. jnaki
    Joined: Jan 1, 2015
    Posts: 10,975

    jnaki





    [​IMG]
    Hey B4U,
    Since most of our sailboats did not have full instrumentation, it was learning to go with out relying on electronics.
    Then one year, we got a larger sailboat with a steering column and full instrumentation, including a depth gauge. The steering wheel and instrumentation pod was too large and took up too much accessible room in the cockpit.

    So, when we sold the larger sailboat several years and harbors later, we got a smaller racing sailboat and purchased our Garmin GPS unit. It clamped onto the tiller and gave us accurate readings in any harbor, ocean or bay. For the next 10 years, we used the Garmin GPS on two sailboats and we enjoyed the room it gave us in an open cockpit.

    It was a good way, to use it along side of our built in compass. We got navigation pin points and knew the waters we were sailing on so, instrumentation was only for speed. It did have some interesting features that could work on any vehicle and even just walking around in a deep forest.

    Before we sold our last racing/cruising sailboat, a full instrumentation package was on the drawing books. But, the location was the holding point as there is limited room and smooth design comes into play.

    Jnaki
    We took it with us on several road trips and thought we could use it when we went walking around coastal forests and trails. It had a compass, directional point finders and with the GPS, told us how fast we were going.(time/distance) So, like your Garmin set up, it could be used as an accessory in any hot rod or street usage at any time.

    The traditionalists will say it is not worth it, as we all have digital phones and map directions. But, the GPS has stuff that is used for specific places, like deserts, mountains and yes, the ocean. Even on strange roadways, it is handy to know where and how fast the next spot will arrive, given the consistent speeds.
     
    Algoma56 and Blues4U like this.
  3. flynbrian48
    Joined: Mar 10, 2008
    Posts: 8,632

    flynbrian48
    Member

    ;)
     
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  4. Black_Sheep
    Joined: May 22, 2010
    Posts: 1,499

    Black_Sheep
    Member

    IMG_4103.JPG I used a Speedhut GPS speedometer, it's accurate assuming that the radar speed enforcement signs are correct. You can totally customize the appearance and add features like turn signal and high beam indicators. The only negative is a short delay while it's acquiring satellites.

    I had them mimic the SW Greenline gauge face on both the speedo and he tach. The cost for the custom artwork was very reasonable.
     
    Last edited: May 7, 2022
  5. Budget36
    Joined: Nov 29, 2014
    Posts: 15,020

    Budget36
    Member

    If you’re too lazy like me and don’t put apps on your phone and if you have an iPhone, hit the button and ask Siri “how fast am I going”?
    You’ll get a chuckle
     
  6. Joe Travers
    Joined: Mar 21, 2021
    Posts: 709

    Joe Travers
    Member
    from Louisiana

    2K in town, 3K in the country, all is well

    Joe
     
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  7. deathrowdave
    Joined: May 27, 2014
    Posts: 4,834

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    I also use App to check speedo correctness after tire changes or just to verify , my calculations .
     
  8. AHotRod
    Joined: Jul 27, 2001
    Posts: 12,290

    AHotRod
    Member

    I have a Speedhut GPS Speedometer in my Model A Coupe (2-5/8" dia. 2-5/8" GPS Speedometer 120mph| SPEEDHUT® Custom Gauges ) and in my Chevy II Wagon. They work perfectly, and there are no other items to have to buy. There quality is first class. We have installed allot of their gauges in customers cars at our Hot Rod Shop, been using them for 12 years now.

    84350248_2551205865156195_8808118110298046464_n.jpg
     
  9. dirt t
    Joined: Mar 20, 2007
    Posts: 5,364

    dirt t
    ALLIANCE MEMBER
    1. HAMB Old Farts' Club

    I've used Speedhut ,there good quality.
     
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  10. Illustrious Hector
    Joined: Jun 15, 2020
    Posts: 571

    Illustrious Hector
    Member

    The accuracy of a gps speedometer is dependant on the input rate transmitted by its satellite. The Garmin units are 3 pulse per second as opposed to say CI's Skydrive 8 or 9 per second. I am installing one in my sedan, early Olds TH400, no speedo drive on tailshaft
     
  11. Slopok
    Joined: Jan 30, 2012
    Posts: 2,955

    Slopok
    Member

    No matter how fast I drive, somebody is always passing me up! :eek:
     
  12. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,426

    Ned Ludd
    Member

    I recall reading up on speedometer converters recently, the ones which allow mechanical speedometers to be used with electronic input by using a speed-controlled electric motor to turn the speedometer's cable input. I came across one which used GPS to calibrate the motor speed controller only. It struck me as the best of both worlds.

    I might have mentioned it on the HAMB. I'll do a search.

    Edit: https://www.jalopyjournal.com/forum...ic-sender-transmission.1220709/#post-13944925

    https://www.speedhut.com/accessorie...-gps-vss-to-mechanical-drive-speed-converter/
     
    Last edited: May 9, 2022
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  13. birdman1
    Joined: Dec 6, 2012
    Posts: 1,674

    birdman1
    Member

    Tachometer, a device that measures engine rpm. Figure out speed at 1000 rpm, do the math. Although I do have a electronic speedometer in my 37 coupe
     
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  14. verno30
    Joined: Aug 25, 2008
    Posts: 1,229

    verno30
    Member

    I used to just run my the tach in several of my cars. 2x+5 was the calculation. 1000 RPM=25mph, 3000rpm=65, ETC ETC.

    Last summer when I bought my '32 3 Window, I used an app on my phone. It was free and did the trick.

    Over the winter, I bought a cheap 5v USB port and GPS Speedometer from Amazon (probably $12 total for both) and wired them in the '32. The speedo was calibrated using my new pickup. It was quite accurate using GM's speedo versus this cheap box. There was even a potentiometer to adjust out small errors. It is now spot on.

    I now have a Speedo, Altimeter, Odometer, Trip Mileage in addition to some other small functions. It is discrete and does what I need.
     
    Budget36 likes this.
  15. i think if i were using one it would be temporary to just get the cable right faster.
     
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  16. squirrel
    Joined: Sep 23, 2004
    Posts: 59,167

    squirrel
    Member

    I use the speedometer app on my phone to check speedometers...if it's a vehicle I'm keeping, I'll go to the trouble to make the original speedometer work properly. The speedos in both my 59 chevy truck, and my Chevy II, are dead accurate.
     
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  17. Do all cable speedos bounce at low speed or is it just worn out ones?
     
  18. squirrel
    Joined: Sep 23, 2004
    Posts: 59,167

    squirrel
    Member

    bounce is usually caused by a bend in the cable.
     
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  19. dirt t
    Joined: Mar 20, 2007
    Posts: 5,364

    dirt t
    ALLIANCE MEMBER
    1. HAMB Old Farts' Club

    Or the cable needs to be replaced or lubricated.
     
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  20. I definitely recommend Speedhut as many have already. Made here in the USA (Utah) and customer service is as good as it gets. My smaller gauges are not Speedhut, I designed the tach and speedo to match the smaller gages I was not replacing at the time.(No hood= trial run with replacement engine) IMG_1745.JPG I just realized this photo was taken on one of my frequented road trip areas.....It's what's been on the news.......unfortunately on fire. So sad.
     
    Last edited: May 11, 2022
  21. 210superair
    Joined: Jun 23, 2020
    Posts: 1,959

    210superair
    Member
    from Michigan

    Mine's off, but I got it down pat what speed I'm going by checking it with the GPS before. And I don't feel like pulling the whole dash apart to adjust it. Next time it comes off anyway, I'll fix it. Same with my gas gauge. When I first got the car it ran outta gas at 1/4 tank and I thought wtf. Then when I filled it up it went up to full and 1/4! Lol. Theft deterrent.
     
  22. I have one (Autometer) in my F-1 and one for the roadster I'm putting together. It's kinda neat to be tracked from outer space!
     
  23. The 39 guy
    Joined: Nov 5, 2010
    Posts: 3,723

    The 39 guy
    Member

    I use a speedway GPS sender with a SW Wings Speedo in my forty coupe. It is very accurate. My sensor is located under the steel cowl. It is slow to find satellites when I back out of the garage. It may take 5 minutes or 3 miles to start working. The other concern is mountain passes with steep cliffs or tunnels. It usually just shows the same speed you entered the area with until it establishes contact with the satellites again.
    IMG_4652R.jpg
    The GPS is mounted on the electrical panel under the dash.
    IMG_4653R.jpg

    When I compare the accuracy of the speedometer to the Garmin I usually use for longer trips they are both reading the same. I recently installed a world class T5 5 speed in my 40. I tried to use a pulse sender with that transmission but it did not work with my SW speedo.

    Would I recommend using GPS? Yes.
     
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  24. I have a Faria Beede GPS speedometer in my car. It came with it so not sure where to get one or how much it was but it works pretty well. Same thing as others have said, it takes a short while to connect to enough satellites to begin working but other than that no issues. Works well for my jalopy that I will be switching rear wheels and tires on often. I think someone made a Smiths faceplate for mine to look older but the faces the company offerrs don't look bad.

    https://fariabeede.com/2-pages/aftermarket.php

    https://fariabeede.com/2-pages/aftermarket.php
     
  25. Happydaze
    Joined: Aug 21, 2009
    Posts: 2,274

    Happydaze
    ALLIANCE MEMBER

    Thanks for pointing that out. I have the same for my 3w 32 project and was wondering if or how the sensor could see the satellite through the steel body, not that I care too much on the how (but remain curious nevertheless) but good to know the answer to the if.

    Incidentally, your panel amused me as it reminds me of a particular pet hate of mine! Why when using a supposedly complete wiring 'kit' is it necessary to add on all manner of additional, seemingly basic, items, such as that pictured? Most annoying but you've covered it nicely.

    Chris
     
  26. The 39 guy
    Joined: Nov 5, 2010
    Posts: 3,723

    The 39 guy
    Member

    Well If I wasn't so anal about circuit protection it wouldn't be so full of extra stuff. There is even a panel in the trunk for a few things located back there. That big black box on the under dash panel is for a turn signal kit ( I am using a stock steering column) . If I had used a modern column I could have used the circuits in that fancy fuse panel;).

    IMG_8971R.JPG IMG_8982R.JPG
    IMG_9187R.jpg IMG_9892R.jpg
     
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  27. gene-koning
    Joined: Oct 28, 2016
    Posts: 5,335

    gene-koning
    Member

    The speedometer in my coupe is whatever the donor vehicle provided, with 187,000 miles on it. When you are below 30 mph, it bounces wildly, so you guess. On our recent 1600 mile trip, according to the yahoo driving directions on my wife's phone, when the speedometer reads 70, I'm actually doing 65, with the speedo reading 30 mph, its actually 28 mph. I have a slight under the dash rattle at 71 mph ( by the phone) and goes away at 74 mph (by the phone), so I kind of have a speed warning system on the highway. I'm a little concerned about what the odometer is telling me, I might not really want to know what kind of gas mileage I'm really getting.

    Maybe a new cable (or maybe even greasing the cable) would be helpful, but boy what a pain that would be to get to under that dash in this car! That much effort might better be spent installing a new set of Speedhut gauges (I've had them before & likes them), but the time delay on getting the speed from a GPS speedometer doesn't appeal very much to me, 3 miles is across town, and that could easily be worth a ticket in this town. On the other hand, I don't have much faith in the old speedometer cable with nearly 200K miles on it that is bouncing, either. My car doesn't have a speed sensor, and I have a flip phone, so those options would be out too.

    Life is so difficult when you don't want to spend money and stuff tries to quit working...
     
  28. alanp561
    Joined: Oct 1, 2017
    Posts: 5,317

    alanp561
    ALLIANCE MEMBER

    That works well. I just put a 5 speed M5R2 in my OT F150 and to get the speed working would have required replacing the automatic steering column with the one from the 5 speed donor truck. I took the truck for a short cruise and matched my speed to the traffic. My daughter GPS'd our speed and I checked the truck's tach which worked for some weird reason. Then I ran the truck through each gear up to the same RPM ( 2500 in this case ) . Third gave me about 45 MPH, Fourth was just over 55 MPH and OD was just over 65 MPH.
     
  29. HotRod-1
    Joined: Jan 17, 2011
    Posts: 29

    HotRod-1
    ALLIANCE MEMBER

    I purchased a Chinese made GPS speedometer from E-Pay for around $50. Took a while to arrive but it installed easily and worked fine. It has the same diameter as the vintage SW speedometers and similar appearance. No noticeable power drain. My only complaint was that the glass was curved and reflected light back to the reader. I couldn't read the needle indication under too many conditions. I found it to be annoying. Thus I removed it.
     
  30. 49ratfink
    Joined: Feb 8, 2004
    Posts: 22,527

    49ratfink
    Member
    from California

    this does not sound very traditional.
     

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