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Converting to a mn6 from a mn12

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Old 04-22-2012, 11:23 PM   #1
fotoboy
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Default Converting to a mn6 from a mn12

I have a buddy w a c5zo6 w a 441 ci putting down around 580 to the wheels. He is looking to convert to a mn6 for road racing. What all is involved with converting to a mn6 from a mn12?
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Old 04-22-2012, 11:39 PM   #2
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Originally Posted by fotoboy View Post
I have a buddy w a c5zo6 w a 441 ci putting down around 580 to the wheels. He is looking to convert to a mn6 for road racing. What all is involved with converting to a mn6 from a mn12?
The ONLY difference is the gear ratio's. If you have access to a good Mn6 just swap tranny's. It's a simple swap. If you want to just swap gear then it gets to be fun since you get to disassemble the box.

Here is the gearing:

........MM6...............M12
1st ....2.66...............2.97
2nd....1.78...............2.07
3rd....1.30...............1.43
4th....1.00...............1.00
5th....0.74...............0.84
6th....0.50...............0.56
Rev....1.91...............3.28
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Old 04-23-2012, 08:49 AM   #3
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Not a big deal. many guys take out the MN12 for an MN6 or have it rebuilt
RPM trans can do it.

But use a .84 5th gear and a .75 or .6 for 6th gear

Dog rings are nice too, no lift shift
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Old 04-23-2012, 12:09 PM   #4
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Originally Posted by fotoboy View Post
I have a buddy w a c5zo6 w a 441 ci putting down around 580 to the wheels. He is looking to convert to a mn6 for road racing.
For a road racer, should look at the ZR1 gear ratios also:

ME2 --------2012 stock
1st - 2.26
2nd - 1.58
3rd - 1.18
4th - 1.00
5th - 0.71
6th - 0.50

MH3----------2009-2011(2012 w/ PDE)
1st - 2.29
2nd- 1.61
3rd - 1.21
4th - 1.00
5th - 0.81
6th - 0.67

I think these are correct, best to call RPM Transmissions for answers

IMHO

Jim

Last edited by jjtoma; 04-23-2012 at 12:28 PM.
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Old 04-23-2012, 12:27 PM   #5
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Originally Posted by AU N EGL View Post
Not a big deal. many guys take out the MN12 for an MN6 or have it rebuilt
RPM trans can do it.

But use a .84 5th gear and a .75 or .6 for 6th gear

Dog rings are nice too, no lift shift


If I get my MN12 refreshed I'm going with MN6 1-4 and MN12 5-6 gears. Not interested in pulling 200mph in 5th, I'd rather have useability.
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Old 04-23-2012, 01:54 PM   #6
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ZR1 gear ratio is too close together for that much HP
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Old 04-23-2012, 02:10 PM   #7
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Originally Posted by AU N EGL View Post
Not a big deal. many guys take out the MN12 for an MN6 or have it rebuilt
RPM trans can do it.

But use a .84 5th gear and a .75 or .6 for 6th gear

Dog rings are nice too, no lift shift
Funny that GM put the MN12 in there to make the car seem more like a track car. Then, the track guys take it out in favor of the Coupe transmission. Are the guys doing the swap still around the same power level as stock?
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Old 04-23-2012, 02:59 PM   #8
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First of all, let's get the RPO's right.

MN6 is the code for the manual transmission option.
MM6 is the 2.66 first gear T56.
M12 is the Z06 2.97 first gear T56.

Quote:
Originally Posted by ysb02 View Post


If I get my MN12 refreshed I'm going with MN6 1-4 and MN12 5-6 gears. Not interested in pulling 200mph in 5th, I'd rather have useability.
The M12 AND MM6 share the EXACT same 5/6 gears. The difference in ratio is the head gear reduction and NOT the 5/6 gears.

TR6060 transmissions can be set up for any combinations on the overdrive.
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Old 04-23-2012, 03:10 PM   #9
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Quote:
Originally Posted by Tech View Post
Funny that GM put the MN12 in there to make the car seem more like a track car. Then, the track guys take it out in favor of the Coupe transmission. Are the guys doing the swap still around the same power level as stock?
YES. the Zr1 gear ratio ( modeled after the GM Motorsports gear box) would be the ideal choice for a road course with a 3.73 or 3.90 gear.

On the ZR1 it is also very good, but north of 580 to the ground, that is wheel speed or could be in each gear

Hell I only run 400 to the ground and I can wheel speed in 3 gears.

the MN12 was to get better Zero to 60 times, the MN12 3-4 is a great combo, but the 2-3 is too much of a jump.

part of the other challenge is with the MN12, 3rd is too high for many low speed corners,but 2nd is too low, where the mn6 3rd is just a better gear for many corners.
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