Have question about electronic speedos - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bgood · 10-26-2004, 08:45 PM

Fellas I'm getting down to the fine dteails on the T56 install and now I need speed detection! I believe autometer electronis speedo would be he way to go but has anyone done this? I need details like how to wire the sender... which terminal gets the +12V and are any additional devices required? I'll probably talk to the techs at AMeter but would appreciate hearing from you guys' experiences.
I'm hoping this meter will resemble the OEM of my 67 any other suggestions?
http://hp.autometer.com/products/spo...ch_speedo.html

Thanks in advance, Bill

68C15 · 10-26-2004, 09:59 PM

I may be wrong here but I believe the speed sensor you are referring to is a PM generator (permanent magnet). what it does is generate an AC voltage which is in the form of a sign wave. the module or in your case the speedo recieves this signal & translates it to a square wave via a analog to digital converter. it doesnt matter which is pos or neg. it will work the same each way. just like a wheel speed sensor on an ABS system. of course this is just for a 2 wire sensor. if it a 3 wire then it will be polarity sensitive. (like a 5 volt reference wire, a ground wire, & a signal wire) these are called a hall effect sensor. most speedos work with the 2 wire PM generator type circuit though.
Todd the Tech. <hey, that's kind of catchy>

68C15 · 10-26-2004, 10:02 PM

ooops, almost forgot. the wires for the 2 wire sensor should be twisted in a corkscrew fashion to eliminate the possibility of polluted signal. also keep them at least 6 inches away from any spark plug wires or the like. (EMI is bad)

68LSS1 · 10-27-2004, 03:51 AM

The Autometer should be fine and have instructions as far as the wiring. A lot of the LS1 hybrid swap people use them. You can also get a box to convert the speed sensor signal to a cable driven one if you want to retain the stock speedo. If I remember right it was $300.00 but that's been awhile ago so I could be wrong. I can dig up their website if your interested.

Cable X is the name of the company and the box is $294.00

10-26-2004, 08:45 PM	#1
bgood Registered User Join Date: May 2004 Posts: 80	Have question about electronic speedos Fellas I'm getting down to the fine dteails on the T56 install and now I need speed detection! I believe autometer electronis speedo would be he way to go but has anyone done this? I need details like how to wire the sender... which terminal gets the +12V and are any additional devices required? I'll probably talk to the techs at AMeter but would appreciate hearing from you guys' experiences. I'm hoping this meter will resemble the OEM of my 67 any other suggestions? http://hp.autometer.com/products/spo...ch_speedo.html Thanks in advance, Bill __________________ 1967 C10 Short,Step 283\1460 Holley HEI Ign. Borg Warner T56 6 Speed! A-1 Electric life pwr windows PS,PB,Tilt 275\60R'S on Alum Mags all around Vintage Air A\C Grey cloth Buckets

10-26-2004, 09:59 PM	#2
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	I may be wrong here but I believe the speed sensor you are referring to is a PM generator (permanent magnet). what it does is generate an AC voltage which is in the form of a sign wave. the module or in your case the speedo recieves this signal & translates it to a square wave via a analog to digital converter. it doesnt matter which is pos or neg. it will work the same each way. just like a wheel speed sensor on an ABS system. of course this is just for a 2 wire sensor. if it a 3 wire then it will be polarity sensitive. (like a 5 volt reference wire, a ground wire, & a signal wire) these are called a hall effect sensor. most speedos work with the 2 wire PM generator type circuit though. Todd the Tech. <hey, that's kind of catchy> __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

10-26-2004, 10:02 PM	#3
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	ooops, almost forgot. the wires for the 2 wire sensor should be twisted in a corkscrew fashion to eliminate the possibility of polluted signal. also keep them at least 6 inches away from any spark plug wires or the like. (EMI is bad) __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

10-27-2004, 03:51 AM	#4
68LSS1 Registered User Join Date: Dec 2002 Location: Tampa Posts: 1,191	The Autometer should be fine and have instructions as far as the wiring. A lot of the LS1 hybrid swap people use them. You can also get a box to convert the speed sensor signal to a cable driven one if you want to retain the stock speedo. If I remember right it was $300.00 but that's been awhile ago so I could be wrong. I can dig up their website if your interested. Cable X is the name of the company and the box is $294.00 __________________ '68 Short Step LS1/T56, Hydratech, Fatman Fabrications Stage III, Baer, Hot Rods to Hell, US Body, S&W, etc Last edited by 68LSS1; 10-27-2004 at 04:10 AM.



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