Why does M6 have tighter ratios than M12?
Thread Starter
Burning Brakes
Joined: Dec 2001
Posts: 1,244
Likes: 13
From: Laguna Woods, CA
Why does M6 have tighter ratios than M12?
This has been rolling around in my pea brain for a while: why does an M6 have closer ratios than an M12? Oh, and another thing: can you mix'n'match M6/M12 gears to optimize ratios for a particular application?
Regards,
Garibaldi
Regards,
Garibaldi
Safety Car
Joined: Sep 2001
Posts: 4,411
Likes: 1
From: Wilmington NC
Originally Posted by Garibaldi
This has been rolling around in my pea brain for a while: why does an M6 have closer ratios than an M12? Oh, and another thing: can you mix'n'match M6/M12 gears to optimize ratios for a particular application?
Regards,
Garibaldi
Regards,
Garibaldi
I would assume you could mix gear sets but don't know for sure.
Melting Slicks
Joined: Oct 2002
Posts: 2,855
Likes: 0
I prefer the taller 1st gear in the M6 and would also love to have a good close ratio 4 speed with the two higher gears for top end runs, with my 390 rear gears my m6 is probably very close to the same ratio's in the m12--
Thread Starter
Burning Brakes
Joined: Dec 2001
Posts: 1,244
Likes: 13
From: Laguna Woods, CA
Originally Posted by Richin Chicago
Actually every gear in the MN12, other than 4th, including 6th has a higher numerical value. That means each gear in the MN12 has a higher torque multiplication. It makes the Z06 even quicker and with the higher red line allows it to, almost, match the MN6 in speed to gear.
I would assume you could mix gear sets but don't know for sure.
I would assume you could mix gear sets but don't know for sure.
Safety Car
Joined: Sep 2001
Posts: 4,411
Likes: 1
From: Wilmington NC
Originally Posted by Garibaldi
This is counterintuitive to me, though (which doesn't take much, let me tell you). For instance, back in the day, an M22 had 2.20 first to match with the big cammed 350s; cooker motors usually used the M21 (was that the number?) with a 2.52 (or close to that). So putting the wide ratio box behind an LS6 seems weird. Personally I'd rather have a bang-bang-bang six-speed than a wide ratio four speed with two overdrives. What am I missing?
MN6
2.66
1.78
1.30
1.00
0.74
0.50
MN12
2.97
2.07
1.43
1.00
0.84
0.56
Last edited by Richin Chicago; Aug 22, 2004 at 03:14 AM.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Originally Posted by Richin Chicago
It's not really much of a "wider ratio". All the final ratios are just higher numerical values which means more torque in each gear (except for 4th where both cars are 1:1) Think of it this way. 6th gear in an MN12 runs at higher revs (for a given speed) than an MN6. So all the ratios in and MN12 are more "crammed" together when you consider the Z06's higher redline.
MN6
2.66
1.78
1.30
1.00
0.74
0.50
MN12
2.97
2.07
1.43
1.00
0.84
0.56
MN6
2.66
1.78
1.30
1.00
0.74
0.50
MN12
2.97
2.07
1.43
1.00
0.84
0.56
There are a few coupes here in the South east that have redlines equal to the Z06 - 6650 or so and equal HP & torque). Several of us, Z06 and coupe drivers have noticed, that on the track the Z06 shift much more then the coupes do. example, on some road course the Z06 needs 2nd, 3rd, and 4th where the coupe with the MN6 only needs 3rd and 4th and both cars are about the same speed ( the driver is the only real difference). Where the real challange came in was a Z06 with a 4:10 rear end. That guy need 2, 3rd 4th AND 5th to be equal in speed to the Z0 6 ( MN12 and the coupe ( MN6) and the standard 3:42 rear gear.
Each sift takes a fraction of a second. And each fraction of a second ads up to full seconds that one is OFF the throttle. So i am wondering the less one shifts ( with all the torque vettes have) the faster one can go??
I think this is also what Pratt & Miller with the C5Rs look at each road circurt and put in the approprate gear ratios to maximise, shorter gears for tighter courses and longer gears for high speed circurts.
Good topic
Tom
Le Mans Master
Joined: Jun 2004
Posts: 6,269
Likes: 50
From: Dallas Texas
St. Jude Donor '06-'07-'09-'10
[QUOTE=Richin Chicago]Actually every gear in the MN12, other than 4th, including 6th has a higher numerical value. That means each gear in the MN12 has a hgiher torque multiplication. It makes the Z06 even quicker and with the higher red line allows it to, almost, match the MN6 in speed to gear.
It's a matter of cam timing, the LS 6 cam is more radical than the LS 1, so GM put higher numerical gears in the MN12 instead of the rear to offset the reduced low end torque. 
It's a matter of cam timing, the LS 6 cam is more radical than the LS 1, so GM put higher numerical gears in the MN12 instead of the rear to offset the reduced low end torque.
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Drifting
Joined: May 2002
Posts: 1,274
Likes: 64
From: Prescott AZ Gilbert AZ
Originally Posted by Garibaldi
This is counterintuitive to me, though (which doesn't take much, let me tell you). For instance, back in the day, an M22 had 2.20 first to match with the big cammed 350s; cooker motors usually used the M21 (was that the number?) with a 2.52 (or close to that). So putting the wide ratio box behind an LS6 seems weird. Personally I'd rather have a bang-bang-bang six-speed than a wide ratio four speed with two overdrives. What am I missing?
Joel