I’m looking for technical help or recommendations on: Speedometer
I am confused about how my speedometer. My car is a Eunos and had a 8/5 reduction box fitted (I saw this myself on a ramp). The trip odometer is reading in miles but my speedometer seems to be in km/h scale. It has a revlimiter gauge fitted in km/h scale but marked as mph
^taken from revlimiter website, it is in the correct mph scale
My speedo is working semi correctly reading 10% above actual speed. My question is how can it record miles in odometer but have km/h scale in speedometer? Is there something I missed?
Also if and when the speedo cable or converter box fails what should I replace it with? Converter doesnt seem to be available new, perhaps will need a UK clock and get new set of gauge faces?
Thanks in advance
EDIT: I couldn’t sleep and thought about it a bit more and it makes sense. Both odo and speedo are on km scale and reading miles thanks to the converter. Question still stands what if cable or the converter breaks?
One way is that it can be simply a display on the speedo, like an overlay, a sticker, what the needle points to is arbitrary.
You’ve got me worried now. I swapped a Eunos clock set for one from a UK mk1… Is my odometer ticking over by the km, despite showing miles? As long as the cable matches, I wouldn’t worry about the converter and whatnot. At this point mileage doesn’t really come into consideration when valuing these cars, as they’re reaching the age that new piston rings are taken as a given!
Simple way to tell is drive for a known distance and see how much it increased by. I’m not worried about mine as it’s in good condition, odometer is only used to track maintenance schedule.
Speaking of cables, are they all the same part or are there different types based on UK/JAP, gearbox, final drive ratio etc?
Go for a drive using WAZE on your phone.
Then compare the WAZE gps based speed with what the car is showing.
You can also set a destination in WAZE to get a distance - zero the car trip meter - and compare the distance travelled vs what the car thinks it has travelled.
I’ve got no idea about the drive ratios etc, I was referring to the connector that goes into the back of the dash cluster when I said cables! I can’t imagine the parts are at all different, I believe that the only stipend the car manufacturers have is the illegality of showing a speed/mileage that is too low, so as you already know most tachographs will have a high margin of error over the actual speed and I assume mileage. This is an interesting question but somebody more knowledgeable than me will have to answer it.
