speed cal question

[GaryG]

i have a 96 gt w/ a stock automatic and 3.73 gears, i talked to DM i dont know how many times today trying to get my speedometer accurate, considering i was not told what the stock gear ratio was, im having to play guessing games...when i tried the 2.73 to 3.73 code it was 10 mph in the city then 15 off on the interstate, before DM closed today i asked for a 3.08 to 3.73 code and Robert told me to turn on #'s 3,6,7,9, 10... now its only off by 4 mph ... any help would be tremendously appreciated

also did 3.27's come optional for an automatic gt?

 

[Javi]

Gary there is a website that will tell you what gear were on the car by the VIN.

Let me see if i can find it.
i dont think you had 3.08's maybe 2.73's nor 3.27's

 

[GaryG]

well when i used the 2.73 code that Robert gave me over the phone it was way off and if i use the 1xxxxxxxxx code that comes on the instruction sheet my speedo doesnt work at all

 

[Javi]

cant find it bro, ill keep looking.

so you have the speedcal with what gears to 3.73's?

 

[GaryG]

sry javi, im not understanding what u meant by "with what gears to 3.73's?"

 

[Javi]

I bet you your speeod is off because of the tires.

 

[GaryG]

when Robert and I were talking, he asked me if i had stock tires an i said no i have 315/35/17's

 

[Javi]

dang it, you have an auto and the gear calculator dont have an auto transmission option.

http://www.corral.net/tech/gearcalc.html

 

[Javi]

IMO 4 mph off is not bad.


mine is 15 mph off :laughing5:

 

[GaryG]

4 isnt bad compared to the 15mph that i was at, but it would be nice to have it be accurate

 

[DropTopPony]

Best way to do it is to get a chase car with accurate speedo and drive on the highway both resetting tripometer at same time. When the stock car hits exactly 10 miles you record what yours says. So if its 9.2 or 11.7 etc they will know how off you are and give you the correct sequence. I'm surprised they didn't tell you this.

 

[x182dan]

have you pulled your speedo gear to make sure you have a stock gear in there? I had a similar problem with the speed cal on my 95 with 410s and for some reason the previous owner changed the gear in the tranny

 

[GaryG]

Best way to do it is to get a chase car with accurate speedo and drive on the highway both resetting tripometer at same time. When the stock car hits exactly 10 miles you record what yours says. So if its 9.2 or 11.7 etc they will know how off you are and give you the correct sequence. I'm surprised they didn't tell you this.

well come to find out today, for some reason i looked at my odometer and tripometer and both of them dont work now

have you pulled your speedo gear to make sure you have a stock gear in there? I had a similar problem with the speed cal on my 95 with 410s and for some reason the previous owner changed the gear in the tranny

im going to take my car into work tomorrow and have them check for me

 

[GaryG]

thanks to all of u who helped me out with this! found out it had 3.27 gears in it stock. its accurate in the city an only off by 2 mph on the interstate