Final Drive Ratios from 3.45 to 3.73

[JonnyG2132]

I know there is a formula out there but I cant seem to find it. I know what the final drive numbers are for 3.45 gears in my car, but how do I figure out what the numbers are for 3.73?


3.45 final drive gears

1st - 12.98
2nd - 7.62
3rd - 4.94
4th - 3.71
5th - 2.74
6th - 2.16

3.73 final drive gears

1st - ?
2nd - ?
3rd - ?
4th - ?
5th - ?
6th - ?

Thanks
Jon

[G8 GT V8]

Just find each gear ratio of the trans and multiply it by the differential's gear ratio.

[JonnyG2132]

Just find each gear ratio of the trans and multiply it by the differential's gear ratio.

Alright. How do I find each gear ratio of the trans though? I tried looking that up as well

EDIt:

Is this the trans gear ratios?

The 6L80 (and similar 6L90) is a 6-speed automatic transmission built by General Motors at their Willow Run Transmission plant, in Ypsilanti, MI. It was introduced in late 2005, and is very similar in design to the smaller 6L45/6L50, produced at GM Powertrain in Strasbourg, France. It features clutch to clutch shifting, eliminating the one-way clutches used on older transmission designs. In February 2006, GM announced that they would invest $500 million to expand the Toledo Transmission plant in Toledo, Ohio to produce the 6L80 in 2008.

Gear ratios:
1------ 2----- 3--- 4----- 5---- 6---- R
4.027 2.364 1.532 1.152 0.852 0.667 3.064

[Executor999]

2009 Pontiac G8 4dr Sdn GT

Transmission
Drivetrain: Rear Wheel Drive
Trans Order Code: MYC
Trans Type: 6
Trans Description Cont.: Automatic w/OD
Trans Description Cont. Again: N/A
First Gear Ratio (:1): 4.03
Second Gear Ratio (:1): 2.36
Third Gear Ratio (:1): 1.53
Fourth Gear Ratio (:1): 1.15
Fifth Gear Ratio (:1): 0.85
Sixth Gear Ratio (:1): 0.67
Reverse Ratio (:1): 3.06
Clutch Size: N/A
Final Drive Axle Ratio (:1): 2.92

http://www.pscars.com/gallery/2009/Pontiac/G8/4dr-Sdn-GT_297488.html

[JonnyG2132]

Ok thanks. So then I would multiply each of those numbers by 3.73?

EDIt: I dont see how multiplying everything by 3.73 would be correct. According to this site, the gear ratios for 2.92,3.27, and 3.45 are as follows
------2.92----3.27----3.45

1st - 4.02 -- 3.23 -- 12.98
2nd - 2.36 -- 3.23 -- 7.62
3rd - 1.53 -- 3.23 -- 4.94
4th - 1.15 -- 3.23 -- 3.71
5th - 0.85 -- 3.23 -- 2.74
6th - 0.67 -- 3.23 -- 2.16

[hivoltagedriver]

Here is a cool calculator that you can use to play with ratios, rpm, and speed...

http://www.f-body.org/gears/

To calcualte your final drive ratio in each gear, you just multiply the transmission ratio for that gear with the rear gear ratio that you are running.

[G8 GT V8]

Ok thanks. So then I would multiply each of those numbers by 3.73?

EDIt: I dont see how multiplying everything by 3.73 would be correct. According to this site, the gear ratios for 2.92,3.27, and 3.45 are as follows
------2.92----3.27----3.45

1st - 4.02 -- 3.23 -- 12.98
2nd - 2.36 -- 3.23 -- 7.62
3rd - 1.53 -- 3.23 -- 4.94
4th - 1.15 -- 3.23 -- 3.71
5th - 0.85 -- 3.23 -- 2.74
6th - 0.67 -- 3.23 -- 2.16

That table is messed up...

Sent from my DROID RAZR using Tapatalk 2