trap at 132 speedo at 118

[AN/GSC-52]

What gear should I use to make my speedo more acurate.

Thanks

 

[1KWIKSIX]

What colour speedo gear do you have in the transmission presently? Do you have the original 3:42 rear end gearing in the car or have you changed out the gears in the differential?

Pull the speedo bullet on the side of the tranny and let us know what colour gear is there.

These charts should help you.

http://www.montess.org/speedo_gears.html

http://www.tciauto.com/tc/speedometer-gear-calculator/

 

[AN/GSC-52]

Wow great post, I think its blue but Ill double check.

THANKS

 

[Chuck Leeper]

tall tires?

 

[pacecarta]

pull the speedometer and write 132 where it show 118

 

[turbobitt]

Are you running traditional slicks ? If so the tires will grow significantly and change the reading. Changing the speedo gear to read correctly on the top end may make it inaccurate at the low speeds with lesser tire growth.
AG.

 

[Steve]

Also keep in mind that trap speed may not be the actual MPH at the end of the 1/4 mile. Trap speed is a calculation using 2 sensors-the first is 66 feet before the finish line and the finish line itself. It wll be very close but can vary depending on each car.

You can download a free GPS speedo app and check your speedo's accuracy at normal speeds. My car is pretty accurate at normal speeds around 65-70mph but is off by about 15mph at around 136. I have an aftermarket speedo and I just don't think its that accurate at those speeds but I never worried about it becuase it is accurate under normal conditions.

 

[v6turbo87]

If there is a 145 mph speedometer in the car it could very well be off. This is a common "up garde" that is done to the stock 85mph cluster. I sent mine for recalibration and the guy told me up front he will not be able to get the calibration perfect through the entire sweep of the needle. He sent me the calibration data stating the accuracy at various mph. He starts at 60mph and gets that dead on. This results with slower speeds reading faster and speeds above 60mph reading slower. I believe mine is 130mph @ a reading of 140. Verify your readings with a GPS as a simple gear change will not correct it in both directions.

 

[AN/GSC-52]

Ill check with a gps. I have the digital dash. Then I ll pull the gear and check color.
Im just trying to get it close, I know about trap speed calculation. Just want it closer.

 

[AN/GSC-52]

pull the speedometer and write 132 where it show 118

Digital, phuck stick