Hey Stangers,
If you are running 3.55:1 or larger gears, and a T5, you will not be able to get the right speedo gear to make your speedometer correct. The largest driven gear, for T5s, is 21 teeth and you need a 23 teeth gear to work with the drive gear found in our 94-95 cars.
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm
This link will take you to Dakota Digital who has a good solution to making your speedometer read correctly. For $90 you can avoid pulling the tail shaft, installing a 7 tooth drive gear and a 20 tooth driven gear to make it right. Heck, I would spend $90 just to avoid draing tranny fluid!
The setup isn't as complicated as you think. You have an option of just driving and hitting the up/down button to correct your speedometer.
The correct switch settings are 1,2,4 to off, 3 to on and you want to hook the EEC to OUT1 for the 128K AC our EEC needs. If you want to preset the unit, you can, and then you don't need to set it by driving. This unit needs to be inside the car. I suggest installing it under the shift boot and using the 12VDC that feeds the reverse switch to power the unit. Installed there, all you need to do is pull the shift bezel if you change gears or tire size.
If you want to calculate your speed error use this formula: Assuming 94-95 which has 8 teeth drive gear(green). Use 7 for Fox Mustang trannys
error= (Tire Revs/mile*gear ratio*8*)/1000*driven gear teeth
example: My case 225/60/15 is 815 revs/mile, 21 gear tooth 3.55 ratio
815*3.55*8/1000*21=110.2 or 10.2% fast
Hope this helps
Eric
If you are running 3.55:1 or larger gears, and a T5, you will not be able to get the right speedo gear to make your speedometer correct. The largest driven gear, for T5s, is 21 teeth and you need a 23 teeth gear to work with the drive gear found in our 94-95 cars.
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm
This link will take you to Dakota Digital who has a good solution to making your speedometer read correctly. For $90 you can avoid pulling the tail shaft, installing a 7 tooth drive gear and a 20 tooth driven gear to make it right. Heck, I would spend $90 just to avoid draing tranny fluid!
The setup isn't as complicated as you think. You have an option of just driving and hitting the up/down button to correct your speedometer.
The correct switch settings are 1,2,4 to off, 3 to on and you want to hook the EEC to OUT1 for the 128K AC our EEC needs. If you want to preset the unit, you can, and then you don't need to set it by driving. This unit needs to be inside the car. I suggest installing it under the shift boot and using the 12VDC that feeds the reverse switch to power the unit. Installed there, all you need to do is pull the shift bezel if you change gears or tire size.
If you want to calculate your speed error use this formula: Assuming 94-95 which has 8 teeth drive gear(green). Use 7 for Fox Mustang trannys
error= (Tire Revs/mile*gear ratio*8*)/1000*driven gear teeth
example: My case 225/60/15 is 815 revs/mile, 21 gear tooth 3.55 ratio
815*3.55*8/1000*21=110.2 or 10.2% fast
Hope this helps
Eric