Can a C6 Z51 owner tell me what special gear ratios come with the Z51 package? Are they changing the ratios in the transmission or just the rear end gear?

 

All manuals have 3.42. Fourth is still direct the first 3 are a bit lower.

 

Transmission. The differential in all manual C5s and C6s is 3.42

The transmission gearing in the manual (MZ6) C6 Z51 is the same through the first four gears as the C5 Z06.

Transmission ratios, Base manual vs Z51 MZ6

First: 2.66 vs 2.97
Second: 1.7 vs 2.07
Third: 1.30 vs 1.43
Fourth: 1.00 vs 1.00
Fifth: - 0.74 vs 0.71
Sixth: - 0.50vs 0.57

 

Excellent. Thank you. Now I have to find a book I have packed away since my move back to the Peoples Republic of NY from the (Left Coast) also known as the Socialist Republic of CA that explains what these gear ratios mean and how they enhance the performance versus the standard 6 speed manual setup.

 

All else equal, a car with lower gears (higher number) will out accelerate one with higher gears. This is why it is such an advantage to swap out 2.73 gears for 3.42 gears in an A4 Vette.

The gear ratios are
Base vs Z51
First: 2.66 vs 2.97
Second:1.7 vs 2.07
Third: 1.30 vs 1.43
Fourth: 1.00 vs 1.00
Fifth : 0.74 vs 0.71
Sixth: 0.50 vs 0.57


The final drive ratios are Base vs MZ6 Z51


3.42 x 2.66= 9.0972 vs 2.97 x 3.42= 10.1574

3.42 x 1.7= 5.814 vs 2.07 x 3.42= 7.0794

3.42 x 1.30 = 4.44 vs 1.43 x 3.42 = 4.8906

3.42 x 1.0= 3.42 for both

3.42 x .74=2.53 vs .71 x 3.42= 2.43

3.42 x .50= 1.71 vs .57 x 3.42= 1.95


Transmissions/Final drive ratios:
Z51 MZ6 manual......*base MM6 manual.................*Base MM6 & aftermarket 3.90s
1st...10.15......................*9.09............. ..............*10.37
2nd...7.07.......................*5.81............ ................*6.94
3rd....4.89.......................*4.44............ ................*5.07
4th....3.42.......................*3.42............ ................*3.90
5th....2.43.........................2.53 .............................*2.89
6th....1.95.........................1.71 .............................*1.95

 

Thankx for the #s. BTW do you have the #s for the A6?
Also is the Z51 package in the 06-07 available with A6?

 

Thanks. But now what exactly do those final ratios mean? Something about how many revolutions the rear end gear turns for every one rev of the rear wheels????

 

__GEAR______Mode__or__Option
____________Z06___Std_6-spd___Z51_6-spd___6-spd_Auto___4-spd_Auto
__1st_______2.66____2.66________2.97____ _____4.02________3.06
__2nd_______1.78____1.78________2.07____ _____2.36________1.63
__3rd_______1.30____1.30________1.43____ _____1.53________1.00
__4th_______1.00____1.00________1.00____ _____1.15________0.70
__5th_______0.74____0.74________0.71____ _____0.85
__6th_______0.50____0.50________0.57____ _____0.67
Reverse_____2.90____2.90________3.28____ _____3.06________2.29

Axle Ratio___3.42____3.42________3.42________ _2.56_____2.73(or_3.15)


Gear Ratio times Rear Axle Ratio
__GEAR______Mode__or__Option
____________Z06___Std_6-spd___Z51_6-spd___6-spd_Auto___4-spd_Auto
__1st_______9.10____9.10_______10.16____ ____10.29_____8.35 or 9.64
__2nd_______6.09____6.09________7.08____ _____6.04_____4.45 or 5.13
__3rd_______4.45____4.45________4.89____ _____3.92_____2.73 or 3.15
__4th_______3.42____3.42________3.42____ _____2.94_____1.91 or 2.21
__5th_______2.53____2.53________2.43____ _____2.18
__6th_______1.71____1.71________1.95____ _____1.72
Reverse_____9.92____9.92_______11.22____ _____7.83_____6.25 or 7.21

Yes, you can get the Z51 handling package with the A6, but the A6 rear axle ratio will still be 2.56.

 

Two very good articles which explain it a lot better than I can:

http://www.chevyhiperformance.com/te...o_calculating/
http://www.gears-manufacturers.com/gear-ratios.html

 

this looks like it's saying the mn6 c6 has the same gearing as the c6 z06.

 

Any Idea what the ratio would be on the 2005 A4 with the Z51 package?

 

It does. The Z06 at 505hp, has a significant horsepower increase over the base cars and does not need gearing as aggressive as found in the manual Z51.

The A4 with the Z51 package had 3.15 gears in it. The transmission gearing was as follows.

First: 3.06
Second: 1.63
Third: 1.00
Fourth: 0.70
Fifth: -
Sixth: -
Reverse: 2.29
Final drive ratio: std: 2.73; opt: 3.15

For the A4 with Z51 multiply 3.15 by the respective transmission gearing to get the final drive ratio.

1st 3.15*3.06= 9.639
2nd 3.15*1.63= 5.134
3rd 3.15*1.00= 3.15
4th 3.15*.70=2.205

 

2005 A4 Z51 has a 3:15, 2005 w/o Z51 has a 2:73. The 3:15 was also available w/o Z51 as an option ONLY in 2005.