electronic speedo
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From: McAlester, OK
electronic speedo
I was just wondering how these things measure speed. I'm interested in the Dolphin 4-in-ones and don't want to run around looking for the right gear or my tires and rear gear.
Clayton
Clayton
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Joined: Apr 2003
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From: Sao Paulo, Brazil
electronic speedo
Clayton,
As far as I know, electronic speedometers work like this:
You’ll have 3 wires going to the speedometer. A positive, a negative and one wire that senses the signals generated by a part goes into the transmission.
This part, the sending unit, generates pulses, something like the points on a distributor. It’s a magnetic switch. The speedometer reads these pulses, and shows you the speed you’re going.
Other than the electronic stuff, they work just like a regular speedometer. You’ll need the correct gear for the sending unit.
This is the way the speedos I’ve worked with work. I don’t know if the Dolphin use a different system.
Hope it helps, better yet, hope you can understand it.
Regards,
Lobo
As far as I know, electronic speedometers work like this:
You’ll have 3 wires going to the speedometer. A positive, a negative and one wire that senses the signals generated by a part goes into the transmission.
This part, the sending unit, generates pulses, something like the points on a distributor. It’s a magnetic switch. The speedometer reads these pulses, and shows you the speed you’re going.
Other than the electronic stuff, they work just like a regular speedometer. You’ll need the correct gear for the sending unit.
This is the way the speedos I’ve worked with work. I don’t know if the Dolphin use a different system.
Hope it helps, better yet, hope you can understand it.
Regards,
Lobo
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Joined: Feb 2001
Posts: 6,328
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From: Iowa
electronic speedo
Clayton
Not certain about the Dolphins but they are probably similar to VDO. It is like Lobo describes with the following exception. You don't need a correct speedo gear. The speedo is computerized and calibratable using several methods. You can fine tune it if you find it is off a bit. Pretty slick.
The speedo is driven with a hall effect switch, inductive/magnetic three wire sender as Lobo says. With VDO, you can use a factory sender or one from VDO for about 60 bucks to fit your specific tranny.
Here's the VDO link. Not trying to talk you out of the Dolphins, but you might find the VDO site informative.
http://www.vdona.com/aftermarket/aftermarket.html
Not certain about the Dolphins but they are probably similar to VDO. It is like Lobo describes with the following exception. You don't need a correct speedo gear. The speedo is computerized and calibratable using several methods. You can fine tune it if you find it is off a bit. Pretty slick.
The speedo is driven with a hall effect switch, inductive/magnetic three wire sender as Lobo says. With VDO, you can use a factory sender or one from VDO for about 60 bucks to fit your specific tranny.
Here's the VDO link. Not trying to talk you out of the Dolphins, but you might find the VDO site informative.
http://www.vdona.com/aftermarket/aftermarket.html
Senior User
Joined: Apr 2003
Posts: 192
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From: Sao Paulo, Brazil
electronic speedo
'fenders,
Thanks correcting what I said before. I completely forgot about those computerized models that allow you to calibrate them... All the speedos I worked with, were taken out of other cars, and modified to fit inside old speedometers, to retain the stock look. That’s why I needed different gears… I couldn’t find an easier way to calibrate them once instaled. I also use a special machine to calibrate the speedo itself, before getting into changing gears out. It's very complicated. Not a fun project...
Thanks again and sorry about that.
Lobo
Thanks correcting what I said before. I completely forgot about those computerized models that allow you to calibrate them... All the speedos I worked with, were taken out of other cars, and modified to fit inside old speedometers, to retain the stock look. That’s why I needed different gears… I couldn’t find an easier way to calibrate them once instaled. I also use a special machine to calibrate the speedo itself, before getting into changing gears out. It's very complicated. Not a fun project...
Thanks again and sorry about that.
Lobo
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From: Ventura County, CA
electronic speedo
Originally posted by 41clay
I was just wondering how these things measure speed. I'm interested in the Dolphin 4-in-ones and don't want to run around looking for the right gear or my tires and rear gear.
Clayton
I was just wondering how these things measure speed. I'm interested in the Dolphin 4-in-ones and don't want to run around looking for the right gear or my tires and rear gear.
Clayton
I have VDO gauges in my '59. I believe they are very similar to the Dolphin gauges, at least in appearance. I also noticed that EZ Wire wiring sells Dolphin gauges. You might check their prices and/or ask them what speedo gears you'll need for whatever (?) tranny you're running in your truck.
I got the VDO's from Bob's F-100 and then my local Ford dealer (of all places !!!) was able to determine what amount of "toothing" speedo-gear I'd need. So that solved my calibration dilemma. Simple to install speedo gear; even I could do it!!!
Let me know if I can help further...
Regards,
Daryl
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From: McAlester, OK
electronic speedo
Thanks. I was looking at Dolphin because of the fact that they have cheap quad guages and I didn't think VDO had them. Another cool thing is that I was surfing the Doplhin site and found an adapter for a '51-52 Ford truck, heh heh. Besides VDO only goes to 120mph. Anyways, thanks again.
Clayton
Clayton
