Speedo confusion
 

On my 07 GT I recently did a magnaflow exhaust, a jlt cold air and a sct tuner with the only changes from stock are 91 octane fuel and jlt cold air set up. I have noticed that I have to drive "faster" to keep up with traffic. IE. 130 km on hwy 1. Now it used to be 120km. Now the AMA here in alberta were so kind to set up mileage markers. Over the 5km test section I am out approx. 350m on my odometer. So would that translate to 3.5 km over 50 km and 7km over 100 km?? That would put my speedo out about 7% which would account for the "faster" driving. How do I fix this????

Check the gears and tire sizes in the tuner. You may well have to adjust them. If the tire size is revs per mile just go to the miata site to do the calcs.

Tire size calculator

It is possible that the other drivers around you are speeding and not paying attention to the posted mileage signs or it could be that your tire sizes are affecting the speed calculations. The speed calculations should be adjustable within the parameters of your SCT Tuner. If you can't make the adjustments with your current programmer setup you should contact SCT. Perhaps the tire adjustments can be sent to you via email to download to your programmer.

I am running stock tire size. And its not just on the highway its everywhere. So either everyone in the province took up driving faster in the last week or its me. I will hook up the tuner and see what is going on.

Check the tire size and gear ratio on the tuner. Depending on the tuner you used I had one of them set for 4:10's.

Agree with the above.Make sure the settings are correct in your tuner/programmer,

its summer now ppl are going faster

Ok so on that miata site it came up with 742 revs/mile. And I am running stock gears which I am guessing are 3.31:1. I will try to set the tuner to this and let you guys know what happens.

Auto or manual tranny?

Manual tranny, on the tuner I set the revolutions to 740 (no 742) and the gears were at "stock" I haven't taken it out and really tested it yet though.