Speedo correction
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,600
Likes: 88
From: Springfield PA
Philly 'Burbs Events Coordinator
Speedo correction
I'm going from 3.54 to 3.73 gears. Since I have a '93 I need to change the speedo gear. Anyone know which one I need? Maybe a part number?
:cheers:
:cheers:
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,600
Likes: 88
From: Springfield PA
Philly 'Burbs Events Coordinator
Re: Speedo correction (scorp508)
You need the one that drops your speed down by 5.0938%. :jester
Safety Car
Joined: Jul 2001
Posts: 3,667
Likes: 0
From: TurtleCreek Twp Ohio
Cruise-In III Veteran
Re: Speedo correction (Rex Ruby)
Rex, from what EricVonHa has told me it seems as though this is for a 93 ZF car, right? If so, you're stock rear end ratio is a 3.45. This is important when you talk to Cyberdyne. They make an electonic interface that converts the speed sensor output of your trans without having to take the trans apart! Here is a link: http://www.dougrippie.com/drm/drive_...tm#Speedometer Calibration Service
Racer
Joined: Sep 2001
Posts: 436
Likes: 1
From: Tampa FL
Re: Speedo correction (Rex Ruby)
anyone :)
# Driven Gear Teeth = [ [(20168/Tire Diameter in inches)] x #Drive Gear Teeth x Axle Ratio ] / 1001
If you, for example, have a 25" diamater tire, 15 teeth sleeve gear, and want 3.73 ratio, then you would need a 45 teeth driven gear according to the above formula.
GM parts numbers for speedo gears are:
Part No. Teeth Color
25513042 35 Orange
25513043 36 White
25513044 37 Red
25513045 38 Blue
25513046 39 Brown
25513047 40 Black
25513048 41 Yello
25513049 42 Green
25513050 43 Purple
25513051 44 Dk Gray
25513052 45 Lt Blue
I know finding spedo calibration gears for 4.10 requires the 13 teeth sleeve, which is pretty hard to find -- and pricey if you can find them.
Perhaps other can jump on and confirm the above, but pretty sure this is fine.
