C5 verseC5Z06 M6
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
yes there is a difference... The tranny in the Z06 is the M12, which was only available in the Z06.. The M12 has different gear ratios, geared for better acceleration and keeping the engine in the sweet spot for optimim performance,... In order to get similar results with the mn6 tranny which all the other corvettes have, you would have to put in the equivelent of a 3.90 gear ratio.. Here is a link with the specific info on the different transmissions http://www.corvetteactioncenter.com/...2002specs.html
here is another link on the m12 tranny http://www.idavette.net/hibz06/page4.htm
here is another link on the m12 tranny http://www.idavette.net/hibz06/page4.htm
Last edited by David426; Apr 26, 2010 at 03:04 PM.
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
you were told wrong my friend.. Look at the first link i sent you.. It breaks down the ratios between the 2 transmissions.. 5th gear is where both cars top out.. The z06 with its m12 tranny and a shorter gearing in 5th gear actual tops out at 170mph in 5th gear at the red line 6500rpm.. The m6 which you have tops out at around 173... Interesting stuff. Actually the coupe is 3-4 mph faster on the top end due to an aerodynamic difference over the convertible.. The C5 coupe also has an aerodynamic advantage over the Z06
Last edited by David426; Apr 26, 2010 at 03:24 PM.
Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
As David426 has written, the C5 Z06s use a MN12 transmission.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
As you can see on the graph, the MN12 transmission's ratios - BLUE line - causes your engine's RPM to drop below the torque peak on the first three shifts and on the 5/6 shift.
The MN6 transmission only causes your RPMs to drop below the torque peak on the 1/2 and 5/6 shift.
I have recently purchased a new C6 ZR1 MH3 transmission to replace a Custom MN6 trans where I had 6th gear changed from 0.50:1 to 0.563:1. The Custom MN6 trans' RPM loss is shown in PURPLE.
I am having 1st gear in the MH3 trans changed from the Chevrolet selected 2.29:1 to a more street-friendly 2.423:1. The graph for this transmission is shown in GREEN.
The MN12 transmission would be my last choice!
Good luck with your Corvette.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
As you can see on the graph, the MN12 transmission's ratios - BLUE line - causes your engine's RPM to drop below the torque peak on the first three shifts and on the 5/6 shift.
The MN6 transmission only causes your RPMs to drop below the torque peak on the 1/2 and 5/6 shift.
I have recently purchased a new C6 ZR1 MH3 transmission to replace a Custom MN6 trans where I had 6th gear changed from 0.50:1 to 0.563:1. The Custom MN6 trans' RPM loss is shown in PURPLE.
I am having 1st gear in the MH3 trans changed from the Chevrolet selected 2.29:1 to a more street-friendly 2.423:1. The graph for this transmission is shown in GREEN.
The MN12 transmission would be my last choice!
Good luck with your Corvette.
Last edited by Pumba; Apr 26, 2010 at 03:28 PM.
Burning Brakes
Joined: Apr 2009
Posts: 946
Likes: 2
What you were told is incorrect. 4th gear is the only common gear ratio (1:1).
Lot's of good info in that thread lol and in this one!
Here are the gearing differences between all transmissions in the C5
A4... MM6 MM12
3.06 2.66 2.97 -- 1st gear (MM12 16.5% shorter)
1.63 1.78 2.07 -- 2nd gear (MM12 16.3% shorter)
1.00 1.30 1.43 -- 3rd gear (MM12 10% shorter)
0.70 1.00 1.00 -- 4th gear (same)
----- 0.74 0.84 -- 5th gear (MM12 13.5% shorter)
----- 0.50 0.56 -- 6th gear (MM12 12% shorter)
2.29 2.90 3.28 -- reverse
Taller gears (numerically lower) give you better mileage, and taller gears work better for top speed. Cars with tall gears and low torque (not the C5 situation) end up using the shifter like a row boat. Taller gears "work the engine harder" as it takes longer to spin up the engine through the RPM band, but the trade off is a higher top end speed (thus are "taller").
Shorter gears (numerically higher) provide you with better acceleration, but you are higher in the rpm band at any given speed (all other things being equal), so you use more fuel. So shorter gears accelerate the car faster by climbing through the rpm range of the motor faster, but at the expense of top end speed (thus are "shorter")
Everything I just said is also impacted by the final drive gear. So, for example, a car equipped with an MM6 and 3.15 r&p is relatively the same as the same car with and MM12 and 3.05 r&p (at least in first gear)
As you can see, the MM12 is shorter in every gear but 4th, when compared to the MM6. What that translates too is a quicker revving engine, quicker acceleration and lower top end speed (unless you change your ring and pinion to compensate). The gearing is actually *not* closer together but the engine is revving quicker, making it seem so. The gearbox when viewed in total is actually "wider" than the MM6 with the 6th gear ratios being pretty close.
A4... MM6 MM12
3.06 2.66 2.97 -- 1st gear (MM12 16.5% shorter)
1.63 1.78 2.07 -- 2nd gear (MM12 16.3% shorter)
1.00 1.30 1.43 -- 3rd gear (MM12 10% shorter)
0.70 1.00 1.00 -- 4th gear (same)
----- 0.74 0.84 -- 5th gear (MM12 13.5% shorter)
----- 0.50 0.56 -- 6th gear (MM12 12% shorter)
2.29 2.90 3.28 -- reverse
Taller gears (numerically lower) give you better mileage, and taller gears work better for top speed. Cars with tall gears and low torque (not the C5 situation) end up using the shifter like a row boat. Taller gears "work the engine harder" as it takes longer to spin up the engine through the RPM band, but the trade off is a higher top end speed (thus are "taller").
Shorter gears (numerically higher) provide you with better acceleration, but you are higher in the rpm band at any given speed (all other things being equal), so you use more fuel. So shorter gears accelerate the car faster by climbing through the rpm range of the motor faster, but at the expense of top end speed (thus are "shorter")
Everything I just said is also impacted by the final drive gear. So, for example, a car equipped with an MM6 and 3.15 r&p is relatively the same as the same car with and MM12 and 3.05 r&p (at least in first gear)
As you can see, the MM12 is shorter in every gear but 4th, when compared to the MM6. What that translates too is a quicker revving engine, quicker acceleration and lower top end speed (unless you change your ring and pinion to compensate). The gearing is actually *not* closer together but the engine is revving quicker, making it seem so. The gearbox when viewed in total is actually "wider" than the MM6 with the 6th gear ratios being pretty close.
Last edited by TurboBerserker; Apr 26, 2010 at 03:28 PM.
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Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
You may want to recalibrate the grey matter.
As the graph shows, the shift point is 7,000 rpms. That is not early for me, but perhaps you are turning your motor higher than the averge LS engine owner.
Le Mans Master
Joined: Nov 2003
Posts: 8,308
Likes: 157
From: NJ
As David426 has written, the C5 Z06s use a MN12 transmission.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
As you can see on the graph, the MN12 transmission's ratios - BLUE line - causes your engine's RPM to drop below the torque peak on the first three shifts and on the 5/6 shift.
The MN6 transmission only causes your RPMs to drop below the torque peak on the 1/2 and 5/6 shift.
I have recently purchased a new C6 ZR1 MH3 transmission to replace a Custom MN6 trans where I had 6th gear changed from 0.50:1 to 0.563:1. The Custom MN6 trans' RPM loss is shown in PURPLE.
I am having 1st gear in the MH3 trans changed from the Chevrolet selected 2.29:1 to a more street-friendly 2.423:1. The graph for this transmission is shown in GREEN.
The MN12 transmission would be my last choice!
Good luck with your Corvette.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
As you can see on the graph, the MN12 transmission's ratios - BLUE line - causes your engine's RPM to drop below the torque peak on the first three shifts and on the 5/6 shift.
The MN6 transmission only causes your RPMs to drop below the torque peak on the 1/2 and 5/6 shift.
I have recently purchased a new C6 ZR1 MH3 transmission to replace a Custom MN6 trans where I had 6th gear changed from 0.50:1 to 0.563:1. The Custom MN6 trans' RPM loss is shown in PURPLE.
I am having 1st gear in the MH3 trans changed from the Chevrolet selected 2.29:1 to a more street-friendly 2.423:1. The graph for this transmission is shown in GREEN.
The MN12 transmission would be my last choice!
Good luck with your Corvette.
That's interesting. I look at some of my 1/4 mile logs to see if things coincide.
In your modified M6 did you have different ratios than standard?
Last edited by robz; Apr 26, 2010 at 04:44 PM.
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
The ls6 redlines at 6500 rpm if you shift at the red line through the 1st 4 gears the tach will drop down to 4800-4900 rpm in the next gear torque peak is at 4800rpm.... This is exactly what you want..GM hit the bullseye on this. I.m not sure why the 7000 rpm shift point is being used in the graph or where the high 5000 rpm torque peak number is coming from.. Obviously from a very modified car.. Even if you shifted at 7000 rpm with the m12 you would be up around 5300 for the next gear
Last edited by David426; Apr 26, 2010 at 05:15 PM.
Racer
Joined: Oct 2000
Posts: 483
Likes: 3
From: Woodstock Ga
As David426 has written, the C5 Z06s use a MN12 transmission.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
...SNIP...
The MN12 transmission would be my last choice!
Good luck with your Corvette.
The MN12 transmission's gear set causes a more significant loss of RPMs than the MN6 or the new MH3 that is used in the C6 ZR1:
...SNIP...
The MN12 transmission would be my last choice!
Good luck with your Corvette.
Like I said, I'm probably thinking about something wrong there. At least for it's intended application of the stock Z06/LS6, it seems like the MN12 should be ideal. Can't see GM dropping the ball there with the tranny selection when that setup was selected specifically for max performance.
Last edited by GM Fan; Apr 26, 2010 at 05:32 PM.
Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
The ls6 redlines at 6500 rpm if you shift at the red line through the 1st 4 gears the tach will drop down to 4800-4900 rpm in the next gear torque peak is at 4800rpm.... This is exactly what you want..GM hit the bullseye on this. I.m not sure why the 7000 rpm shift point is being used in the graph or where the high 5000 rpm torque peak number is coming from.. Obviously from a very modified car.. Even if you shifted at 7000 rpm with the m12 you would be up around 5300 for the next gear
For an MN12 transmission on a 1 / 2 shift the following would be the RPMs after the shift:
2.07 / 2.97 x the shift RPM = .696969 x shift RPM
For a 6,500 RPM shift the remaining RPMs = 4,530
For a 7,000 RPM shift the remaining RPMs = 4,879
Don't believe the tach !
Last edited by Pumba; Apr 26, 2010 at 06:08 PM.
Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
You've obviously spent some time on this so I am probably just exposing myself as an idiot here and thinking about this incorrectly, but with a engine with a similar power curve to a stock LS1/LS6 wouldn't you want to drop to just below (but still close to) the torque peak with each shift as opposed to well over it? Wouldn't that give you the benefit of pulling through the meat of the powerband whereas starting over the peak you're doing nothing but dropping off torque wise? If memory serves the torque values drop off pretty sharply once you're past the peak as well.
Like I said, I'm probably thinking about something wrong there. At least for it's intended application of the stock Z06/LS6, it seems like the MN12 should be ideal. Can't see GM dropping the ball there with the tranny selection when that setup was selected specifically for max performance.
Like I said, I'm probably thinking about something wrong there. At least for it's intended application of the stock Z06/LS6, it seems like the MN12 should be ideal. Can't see GM dropping the ball there with the tranny selection when that setup was selected specifically for max performance.
What you never want to do, except on a 1 / 2 shift where you have a higher rate of acceleration and lower aerodynamic resistance, is drop your engine's RPM to or below the torque peak.
GM picked the first and second gear ratio in the MN12 to improve their 0 to 60 times with the C5 Z06s.
Please note that the C6 Z06 uses the MN6 trans, and that the ZR1 uses the MH3 trans. Take a look at their remaining RPMs on the above graph.
Again, the MN12 trans would be my last choice.
