Subscribe'd. 
Retrofitting late model donor speedometers
Retrofitting late model donor speedometers OK, I know enough to be dangerous.
I talked to Autometer at SEMA, and they stated that their speedometers require the tranmission speed sensor output. No problem.
But, like many, I would like to keep the stock appearance of the original speedo face. No problem. Gut and paste in an Autometer/aftermarket gauge with the same sweep angle and speed range, then tap into the transmission output. But a new one is $250, used who knows.
What about using a speedo movement from a late model car? For example, an '02 Impala has a very similar sweep angle speed range that I need plus a digital odometer. These can be had for $25 on Evil Bay. How would one determine if the speedometer uses the same 4kppm input that the LS1 PCM outputs? Calibration might be a PCM tuning deal.
Thoughts?
I talked to Autometer at SEMA, and they stated that their speedometers require the tranmission speed sensor output. No problem.
But, like many, I would like to keep the stock appearance of the original speedo face. No problem. Gut and paste in an Autometer/aftermarket gauge with the same sweep angle and speed range, then tap into the transmission output. But a new one is $250, used who knows.
What about using a speedo movement from a late model car? For example, an '02 Impala has a very similar sweep angle speed range that I need plus a digital odometer. These can be had for $25 on Evil Bay. How would one determine if the speedometer uses the same 4kppm input that the LS1 PCM outputs? Calibration might be a PCM tuning deal.
Thoughts?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Yep, all of the GM electronic speedos use the same signal (4000ppm square wave DC). I looked into doing this and the difficult part was finding one with an odometer in the speedo sweep and not somewhere else in the gauge cluster, but it looks like you may have already found one that would work. Also keep an eye out for aftermarket speedos on evilbay, I picked up an autometer factory second for $50, the lens was scratched but that didn`t really matter since I was prying it off anyway
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TECH Apprentice
Joined: Nov 2006
Posts: 369
Likes: 0
From: Copenhagen
Ive been trying to figure out what pins are what.. i am swapping an LS1/A4 in a 79 malibu, and woul like nothing more than ta adapt the C5 dash i bought to install, tach, spedo, gauges and all (perhaps the HUD someday 
) i even bought the corvette underdash wiring to have all the connectors.. but i have been utterly unseccessfull in finding the schematics!
) i even bought the corvette underdash wiring to have all the connectors.. but i have been utterly unseccessfull in finding the schematics! Trending Topics
Ive been trying to figure out what pins are what.. i am swapping an LS1/A4 in a 79 malibu, and woul like nothing more than ta adapt the C5 dash i bought to install, tach, spedo, gauges and all (perhaps the HUD someday ) i even bought the corvette underdash wiring to have all the connectors.. but i have been utterly unseccessfull in finding the schematics!
) i even bought the corvette underdash wiring to have all the connectors.. but i have been utterly unseccessfull in finding the schematics!LS1 Tech Stories
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I won an auction on Evil Bay for a VDO gauge that says it can accept 500 - 399,999 PPM signal, but VDO has yet to answer if it will accept a square waveform. The guy who programmed the PCM already has it calibrated (tires and gears) for the correct 4000 ppm output.
If the square waveform does not work, does the PCM start throwing codes or act funny if an aftermarket meter is spliced into the transmission sensor output? Seems like some people have problems, some don't.
Like you, I'll gut out what I need from the gauge. The hard part for this one may be relocating the digital odometer to match the original gauge face.
I won an auction on Evil Bay for a VDO gauge that says it can accept 500 - 399,999 PPM signal, but VDO has yet to answer if it will accept a square waveform. The guy who programmed the PCM already has it calibrated (tires and gears) for the correct 4000 ppm output.
If the square waveform does not work, does the PCM start throwing codes or act funny if an aftermarket meter is spliced into the transmission sensor output? Seems like some people have problems, some don't.
Like you, I'll gut out what I need from the gauge. The hard part for this one may be relocating the digital odometer to match the original gauge face.
I'll bet by the time you get done with the conversion box and the trouble, not to mention trying to fit it, an original gauge could be modified by Redline or North Hollywood Speedometer and take the PITA factor out.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
