Speedometer off on my S14 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

JDMspeedS14 · 08-29-2008, 11:50 PM

Hey guys, the other day when I was driving I decided to check my speed with my GPS because people were blowing past me when I was goin 80. The GPS said that I was going 5 miles slower than what my actual speedometer said. I have the S14 SR in my S14 and I used the sensors on the KA trans when I did the swap. Was there something else I needed to change? What could be the problem? My friend said that it may be my tire size, but not sure if that is even relevant. So is my speedo off? or is the GPS not accurate? Thanks Guys.

da1ndonly · 08-29-2008, 11:59 PM

get another car use the gps speedo and see if its accurate with the other car.

projectRDM · 08-30-2008, 12:05 AM

Speedometers are never 100% accurate, even with OE tire sizes. Changing wheel/tire size throws it off even further by changing the overall gearing. 5MPH off is average, some cars are substantially more than that.

JDMspeedS14 · 08-30-2008, 12:10 AM

I used the gps speed thing in another car and it was pretty accurate from what i remember. I had the old falken azenis on the stock 16's and then i put the new azenis on them, which are very low profile. So it could be the tire size? Thanks

da1ndonly · 08-30-2008, 12:25 AM

speed past a cop with a speed gun see how much he clocks you at and what you saw on your dash...lol jk

08-29-2008, 11:50 PM	#1
JDMspeedS14 Join Date: May 2005 Location: Los Angeles, CA Posts: 19 Trader Rating: (0) Feedback Score: 0 reviews	Speedometer off on my S14 Hey guys, the other day when I was driving I decided to check my speed with my GPS because people were blowing past me when I was goin 80. The GPS said that I was going 5 miles slower than what my actual speedometer said. I have the S14 SR in my S14 and I used the sensors on the KA trans when I did the swap. Was there something else I needed to change? What could be the problem? My friend said that it may be my tire size, but not sure if that is even relevant. So is my speedo off? or is the GPS not accurate? Thanks Guys.

08-30-2008, 12:05 AM	#3
projectRDM Post Whore! Join Date: Dec 2002 Location: Atlanta Age: 51 Posts: 13,812 Trader Rating: (12) Feedback Score: 12 reviews	Speedometers are never 100% accurate, even with OE tire sizes. Changing wheel/tire size throws it off even further by changing the overall gearing. 5MPH off is average, some cars are substantially more than that. __________________ FORMERLY R240NA Learn what's really going on and protect your assets now before they're gone forever: www.paypalsucks.com

08-29-2008, 11:59 PM	#2
da1ndonly Leaky Injector Join Date: Jul 2007 Location: Orange Age: 34 Posts: 132 Trader Rating: (1) Feedback Score: 1 reviews	get another car use the gps speedo and see if its accurate with the other car.

08-30-2008, 12:10 AM	#4
JDMspeedS14 Join Date: May 2005 Location: Los Angeles, CA Posts: 19 Trader Rating: (0) Feedback Score: 0 reviews	I used the gps speed thing in another car and it was pretty accurate from what i remember. I had the old falken azenis on the stock 16's and then i put the new azenis on them, which are very low profile. So it could be the tire size? Thanks

08-30-2008, 12:25 AM	#5
da1ndonly Leaky Injector Join Date: Jul 2007 Location: Orange Age: 34 Posts: 132 Trader Rating: (1) Feedback Score: 1 reviews	speed past a cop with a speed gun see how much he clocks you at and what you saw on your dash...lol jk