Well after getting my bama tune I noticed the car accelerates allot faster. Normal right? Well not so fast, I think my speedo is off by about 10mph @80mph.

I have 3.55 gears in the car, at least I think I do as that's what my dealer quoted. It was in the options list.

However using my gps its showing about 10mph slower than the speedo @ 80mph and about 5mph slower @ 55mph. I have a dashhawk pluged in that reads spedo digitally. It matches the actual car spedo.

Anyone have any insight? My car is a 5speed manual.

anyone have rpm mph numbers in relation to gear?

I'm going nutty over this, I don't want to show more miles than I'm actually traveling. Is there a way to check the spedo settings on a diblosport tuner? What should the settings be for a car with 3.55 gears, 5speed manual and 17bullits with 235/55/r17's.

any help appreciated.

 

How bout just drive down any hwy and use the mile markers. Simple as that.

 

I would trust the gps unit.

 

what are you using to tune it? the sct tuners have an option to select tire size so maybe yours was sent to you with the wrong size in it....

plug your tuner in and go through the options maybe theres your answer

 

OK I took the advice of the guys here. I looked up my axle code in my doorjam. In fact it is 3.55gears, the tires rotate @768rpm (revs per mile) I will reflash my car and see if it helps.

It might be the 6% or so that the spedometers are allowed to be inaccurate according to dot spec.

Thanks for the help fellas.