FD3S2005

iTrader: (11)

i noticed when im doing lets say about 70mph on the gauge, my commander would says im doing 106 which is about 65mph. i noticed it is never acurate, is my gauge going bad, of the pfc suppose to read a little off?

cptpain

iTrader: (1)

im sure the commander is displaying speed in km/h

4CN A1R

iTrader: (6)

he said that smart guy...

the pfc should be accurate. i wouldnt trusts your speedo. its common to see 5mph differences, but not till you reach really high speeds.

SLOASFK

iTrader: (5)

The stock speedo is fairly accurate when it's working, especially at cruising speeds.

What size rim/tires are you running? I believe if you're rolling on greater than a total 26" wheel diameter, then it will make your speedo read low. Check out sucklab's chart in the tire/rims section.

https://www.rx7club.com/suspension-wheels-tires-brakes-20/fd-wheel-tire-sizing-416251/

ohjonnybomb

my speedo reads high, 5-7mph faster then Im going at 70

cptpain

iTrader: (1)

sorry, i fail at reading comprehension sometimes

FD3S2005

iTrader: (11)

i have 17' rev rims got them with the car and never really looked into how wide they are (not that wide)

4CN A1R

iTrader: (6)

its no prob...sorry for being such a smart ***

parid

Get a GPS and independently verify what the correct speed is.

DaveW

Check on Tire Rack or other some other tire site to compare your tires' revs/mile to the revs/mile for the stock 225/50-16 size. If they are different, that may be the reason.