Just finished the installation of this bad boy (replaced my MN6).

Pick up (seat of the pants) in first and second is awesome over the MN6.

What a RUSH :yesnod:

 

Should feel like a 3.90 rear..

Just imagine what the 4.10's feel like...

 

Rode in a 3:73, it is at least as good as that!

Have been contemplating the 3:90's, but am really getting concerned that I may be getting way out of control with this speed thing :lol:

 

I had a beefed up MN12 installed sometime back and love it too! I gotta find something to do with the MN6 on my garage floor now. Within the next two weeks it goes in the shop for some body work and then it's heads and cam time.

 

The 2004 Z06/M12 with beefed up forks and guts, should be a great option for high horsepower apps. :cheers:

 

does the 2004 come already beefed up?? :cheers:

 

I want to say that its only available with the Z16 option 2004 Z06.

 

I did the same thing.. went from a MN6 w/3.42's to a MN12 w/3.73's...

OMG.. what a difference.. almost too much!

 

Jeez Tom ....Do you sleep? :D
joel(Bink) :cheers: :steering:

 

nevrenuf,

I agree - it is almost, but not quite, too much - but it is a rush :smash:

 

M12 here also.........and like you all I can say is WOW :) :)

 

Is a MN12 geared different than a MN6?? If so in which gears ?? 1st and 2nd only or also 3rd?? I'm sure 4th is 1 to 1.

:auto: :auto: :auto: :auto:

 

First and second are geared different, as, I think, is thrid. The rest are apparently the same, but need a real gear head to give us the numbers.

 

M-6 ------- M-12
----------------------------------
1. 2.66 ------- 2.97
2. 1.78 ------- 2.07
3. 1.30 ------- 1.43
4. 1.00 ------- 1.00
5. .74 -------- .84
6. .50 ------- .56
R 2.90 -------- 3.28

I guess I'm the gear head you were looking for. This stuff is my life. :banghead:


[Modified by Crashed 94, 9:31 PM 6/11/2003]


[Modified by Crashed 94, 9:32 PM 6/11/2003]

 

What's the Z16 option?

BTW: I just happened to have the word.doc I saved the gear ratio list on up before I read this post...

Question: since 4th is 1:1 for each and I would only need 2nd & 3rd, would it be more cost effective to just have the 2 & 3 gears changed?

 

Ok - here's a stupid question...

Why is fourth 1:1 in both the M6 and M12? I've always felt that fourth in my ZO6 should be shorter because it results in the revs dipping too low on the 3 - 4 shift. Yes, I don't know much about manual transmissions.

The second day I had my car (bought it used w/ 2800 miles on it - so not beating on a brand new car) I raced a Viper from 60 on up. I stayed perfectly even through third - then shifted to fourth, engine bogged (relatively) and he started pulling away.

Do they save money or space somehow by having a 1:1 gear or is it just traditional to have a "drive"?

Anyone know if it's possible/how to get the gears/how expensive it would be to change fourth and sixth gear? I figure something like a 1.1 fourth and 0.65 sixth might be nice - especially if I go heads/cam and have some power left to accelerate in sixth.

 

4th is a straight through shaft, very little loss. I doubt you'll find a kit to change the 4th gear ratio, I'm really not even sure if that'd be possible.

And 4th gear is where I always tend to start walking the vipers/bpu supras i race. Odd.

 

Hi,
An M6 with a 3.90 diff gets rid of the big drop 3rd to 4th. Why would you change both to an M12 and to a higher diff gear? The M12 was a quick way for Chevy to get a stiffer 1-2-3 gear without changing the diff. The cost is a big drop in rpm on the 3-4 shift.
The reason you want a smaller drop at higher speeds is because the aero drag is high which reduced the acceleration (T-D is smaller). The M6 has a very good set of drops in 1-2-3-4 but a 3.42 diff is not stiff enough for good accel in the first 3 gears. That is why a 3.42/M12 will out acell a 3.42/M6 (same car) but a 3.90/M6 will out acell a 3.42/M12 at higher speeds.
Steve






[Modified by SNW Vette, 3:40 AM 6/12/2003]

 

:iagree:

 

Try hanging out third a few rpms higher prior to engaging fourth.

The only thing lower gears (3.70/3.90/4.10's) do is allow you to engage your gearbox's next gear at a slower speed. The lower MN12 gearbox by being geared lower also allows your shift to occur earlier, when compared to an MN6.

Here are the Gearboxes results when multiplied together (gearxgear ratio):

Trans: MN6/3.42....MN6/3.73....MN6/3.90....MN6/4.10........MN12/3.42
1...........9.09..............9.92...... .......10.37.............10.93.......... ...10.89
2...........6.08..............6.64...... .......6.94...............7.31.......... .....7.08
3...........4.44..............4.85...... .......5.07...............5.34.......... .....4.89
4...........3.42..............3.73...... .......3.90...............4.11.......... .....3.42
5...........2.53..............2.76...... .......2.88...............3.04.......... .....2.87

The MN12 is superior in the first three gears even when the MN6 has the 3.73's, until fourth, fifth and sixth. There, the 3.73's will remeain strong, top speed being the limiter.

It should also be noted that the Z06 rear tire height is about .5 inch shorter-adding more rear gear to it effectively (not included in the above math). This .5 inch shorter effectively "gives" the Z06 rear a 3.52 rear end (guestimating).

[Modified by MiamiDave, 9:38 AM 6/15/2003]


[Modified by MiamiDave, 9:49 AM 6/15/2003]


[Modified by MiamiDave, 5:38 PM 6/19/2003]