electronic speedo installation??

Has anyone installed an electronic speedo in conjunction with the car's mechanical gauge? I'd like to confirm MPH accuracy with another speedo while driving. The few I've checked online require a transmission sending unit which apparently disconnects the stock mechanical speedo cable making gauge comparison impossible. Any leads or advice most welcome... thank you!<!-- google_ad_section_end -->

 

Get a GPS instead. It'll tell you your accurate speed and how to find your next Craigs List score.

 

Presuming that you have a tach, just calibrate. This site can help w/ tire size and gearing.
http://www.wallaceracing.com/gear-speed.php

 

Follow a buddy down the road. Have him throw up his hand at some predetermined speed or speeds... say 35, 45, 55, etc...

 

Most phones have a speedo app can be put on it for free. I had a
My iPhone for months before I realized I could use it to calibrate speedo.

 

I have installed two electric speedo's,and both(two different brands)came out right on the money. Simply follow the instructions,using highway mile markers,as set points. The neat thing is,you can reset the speedo every time you change a gear,or tires. I read about a new speedo coming soon,that uses GPS technology to set itself.

 

Mileposts are non-existant in Calif, I found the Auto-Meter instructions to be doable. I then did the "follow a buddy" process, to confirm that I had it right.

4TTRUK

 

Thanks for the terrific comments. Sometimes the solution is right in front of you. Now all I need is 6 to 12V converter to power the GPS!

 

Not really. My Garmin has it's own internal battery that's good for several hours. I think most do.

Bob

 

Yes, I have done it. My T5 has a basic mechanical drive that an electronic adaptor is attached to. The mechanical cable output is brought through so you can use both.
There are no numbers on the adaptor so I can't tell you who made it.

 

I use the local police radar signs by the hospital and other places around town. Some of radar units are mobile and I have to drive around to find them. I think plus or minus 2 or 3 mph is close enough. So far the radar units are celebrated correctly.

 

Problem solved: I downloaded GPS Speedometer Pro to my Android smart phone and it works like a charm! Link:

https://market.android.com/details?...iY29tLmxpbnhtYXAuZ3Bzc3BlZWRvbWV0ZXJwcm8iXQ..