differential ratio's

[7MGTEsup]

Is there such a thing as an accurate speedometer on a Supra?

My speedo is only 4mph out at 100mph, but I recalibrated it by pulling the needle off and rotating it a bit counter clockwise. Its dead on up to 50mph but then starts to go out after that. 70mph speedo is 68mph gps so its pretty good.

 

[ZoomZoomZoom]

ZZZ: Even if you have it calibrated it'll only be accurate at that speed, the odometer should be accurate no matter what as it has a mechanical link to the cable the speedo doesn't.

Good to know !

My speedo is only 4mph out at 100mph, but I recalibrated it by pulling the needle off and rotating it a bit counter clockwise. Its dead on up to 50mph but then starts to go out after that. 70mph speedo is 68mph gps so its pretty good.

I know my speedo is off by how fast the trees go by. I need a more scientific method, haha. I will have to get my car out on the road and compare its speedo to another car. It may be off by a fixed amount, but it doesn't seem like it, according to the trees. If it is a fixed amount, then the recalibration trick will work. Maybe I'll do it regardless for 65 mph so I don't have to do math while driving

 

[Dan_Gyoba]

The axle code in a MA70 will be Gxx4 or Gxx5.

The xx determines the axle ratio. This will be, as I recall, 28, 30, or 31, which is (By memory, I may be wrong) 4.300:1, 3.727:1 and 3.909:1 respectively. My car's axle code is G285, and it came with a 4.300:1 limited slip.

The G indicates an 8" ring gear.

The last digit of "4" indicates that it's a 4 pinion open differential, or a "5" indicates a 4 pinion limited slip. (2 and 3 are open and limited slip for a 2 pinion differential.)