freakasis

does anyone make somthing to adjust the speedo on a civic? i searched and all i could find was stuff for honda motorcycles. i hate having to subtract 9% and then trying to figure out how to go 5mph over the limit.

freakasis

anyone?

TunerN00b

10% is considered acceptable error for a speedometer.

How have you determined that it is inaccurate? Are you using the correct tire size?

freakasis

no im not. i know how off it is because i calculated the tire size differance and i have checked it against police radar. i know what the standards are, but i dont think any amount is acceptable.

TunerN00b

A stock tire for my car is a 195/55-15, with a diameter of 23.5". With 10/32" of tread standard and 2/32" tread at end of life, we're already talking about a 1/2" diameter (3%) change during the course of its life just from wear. When should the speedo be accurate, with new tire, dead tires, or half way worn?

Then we get to account for the fact that pressure changes the rolling diameter of the tire, and we get further inaccuracy. Weight in the vehicle also changes the rolling diameter.

So, shy of GPS based speed detection, I don't think any of us have ever really had truly accurate speedometers.

And thats just the long way of me saying, "I really have no clue how to adjust the damn thing.".

Hope you find the answer you're looking for. Though, the "correct" answer to adjusting the speedo is to use the correctly sized tires.

freakasis

thanx for the help...maybe ill try and wire in a variable resistor into the speedo itself so i can adjust it....not sure if thats possible. i guess ill be reading some circuit diagrams in the future.

basil

I know this is an old thread, but did you ever figure it out???

robinmarkk

Honda won't be able to reprogram because the ECU doesn't control the speedo. The VSS generates a square wave signal which is directly feed into the speedo, and the on-board integrated circuit transforms that signal to the needle motor. For that you can contact your nearest Honda service station.

BrianZ

http://www.yellr.com/