Well I am clueless at this point...
I have an 87 GT with the stocker 3.08 gears and an 89 140mph speedo cluster. I have recently had a fresh T-5 installed in to replace my old, and dying, T-5. When I got it back the speedometer was off by nearly 15mph, but it didn't worry me too much at first. No big deal I thought as I figured I could change the speedo gear and go about my merry way. I started off with the stocker, for my year, 18tooth and the speedo read 5-10mph off consistantly, so that wasn't the fix I was looking for. So I end up sticking a 16tooth gear in (a 16 tooth gear is the smallest gear I can find, mind you) and the sonofabitch still reads 3mph too slow at 50 (Reads 47@50mph) and 5mph too slow at 60(Reads 55@60mph). Well I have gone through every speedo calc in the book, and none of them tell me anything different than a 16t for an 8tooth drive dear or an 18t for a 7 tooth drive gear. Cosequently, I have come to a halt and I have no clue as to what to do now.
That is where you come in...
Maybe a fresh mind can figure out this problem because I don't see myself figuring this one out myself. Maybe I should just get a smaller tire sizee and offset the problem, but seeing that I just dumped 600 bucks into my current tires just 2 months ago, I don't see myself doign that again any time soon. So opinions? Outbursts? Had a good lunch? Anything at all. I just want this to be right again.
Any help would be appreciated. Thanks.
I have an 87 GT with the stocker 3.08 gears and an 89 140mph speedo cluster. I have recently had a fresh T-5 installed in to replace my old, and dying, T-5. When I got it back the speedometer was off by nearly 15mph, but it didn't worry me too much at first. No big deal I thought as I figured I could change the speedo gear and go about my merry way. I started off with the stocker, for my year, 18tooth and the speedo read 5-10mph off consistantly, so that wasn't the fix I was looking for. So I end up sticking a 16tooth gear in (a 16 tooth gear is the smallest gear I can find, mind you) and the sonofabitch still reads 3mph too slow at 50 (Reads 47@50mph) and 5mph too slow at 60(Reads 55@60mph). Well I have gone through every speedo calc in the book, and none of them tell me anything different than a 16t for an 8tooth drive dear or an 18t for a 7 tooth drive gear. Cosequently, I have come to a halt and I have no clue as to what to do now.
That is where you come in...
Maybe a fresh mind can figure out this problem because I don't see myself figuring this one out myself. Maybe I should just get a smaller tire sizee and offset the problem, but seeing that I just dumped 600 bucks into my current tires just 2 months ago, I don't see myself doign that again any time soon. So opinions? Outbursts? Had a good lunch? Anything at all. I just want this to be right again.
Any help would be appreciated. Thanks.
