i know that the yellow box requires a 11% change from stock, however with the tires i have should i change that 11% to something else? my tires are 245/40/17 also if somone has a write-up of the yellow box install with pics that would be great. thanks.

 

Since you didn't mention it, I assume that you're talking about 4.56 gears (which would be 11.2% by themselves). Those tires you are using would only introduce about a 0.3 mph (or less) difference at about 150 mph. This is not enough to worry about. You will have a bigger error just from the natural OEM speedo error, which has been determined to be anything from dead on to 2%. If you truly want a perfectly accurate speedometer, you'll need to get paced by a known calibrated source like a police car, mileage test markers on the highway, etc. Then you calculate the % error and dial that into the YB.

 

use the mile markers, method given in the yello box instructions. be done with it.

i didnt think there was that much err (2%) in the oem digital driven system but 2% is very small.

 

2% is about the max I've heard of. Like I said, most S2000's are "dead on".

 

thanks for the input guys.