1LE (MM6) Gearing?

[Higgs Boson]

Keep in mind the rear tire on a 1LE is an inch shorter than the SS. This will increase RPMs per MPH.

[bannonm]

Originally Posted by Higgs Boson

Keep in mind the rear tire on a 1LE is an inch shorter than the SS. This will increase RPMs per MPH.

I think it's 27.9" vs. 28.6". Shorter yes, but not quite an inch. I run 285/35 Pilots and they are 27.9" too. The shorter tires make the car feel quicker.

[blazzin1]

Originally Posted by SP33D

10.42 engine revolutions for every wheel revolution.

Thanks for the clarification, I did have my thinking backwards. I'm still not sure in my head how the higher number of engine revolutions translates into more torque, but I'll go with it. Wouldn't be the first time I didn't quite understand how something works!!!!

[MikeOD]

Originally Posted by blazzin1

Like on the MM6 above, for 1st gear, isn't it, for every one turn of the driveshaft, the rear wheels turn 10.42 times?? Or is that backwards???

Backwards, 2.66 turns of the crank is 1 turn of the drive shaft, and then 3.91 turns of the driveshaft is 1 turn of the tires. 2.66 * 3.91 = ~10.42 turns of the crankshaft per rotation of the tires in first gear.

Originally Posted by DanSS24

I'm pretty sure the GM engineers are being conservative, but it is up to the consumer to take a chance. My 98 Camaro SS trans was only rated up to 400 lb/ft torque, but it handled well pass 450 when I upgraded it. And never had a problem, even with a 3000 stall torque converter. But then again, that was just an auto trans. Not sure about manual trans.

I believe all 94-2002 MM6 T56's are rated at 450 ft*lbs, not 400...but yes you're right, people put more through them a lot. The only significant difference in 94-97 and 98-2002 F-Body T56's was the input shaft/front plate/bellhousing/slave cylinder change for 98...the 2 1993 T56's in the F-body were rated to lower torque because of first gear.

A LOT of the torque rating of the trans has to do with 1st gear. The "shorter" first gear is, the more it multiplies the torque that the main shaft see's, and the more it's able to break it...after that, the next culprit is the main shaft diameter...the strongest T56's have larger diameter output ends of the main shafts than the lower rated T56's...the strongest way to build one with OEM parts for example is an MM6 gear set from a 2006/2007 ZO6, and an SSR 32 spline main shaft. (takes some machining to cobble together)

[DanSS24]

Originally Posted by MikeOD

I believe all 94-2002 MM6 T56's are rated at 450 ft*lbs, not 400...but yes you're right, people put more through them a lot. The only significant difference in 94-97 and 98-2002 F-Body T56's was the input shaft/front plate/bellhousing/slave cylinder change for 98...the 2 1993 T56's in the F-body were rated to lower torque because of first gear.

A LOT of the torque rating of the trans has to do with 1st gear. The "shorter" first gear is, the more it multiplies the torque that the main shaft see's, and the more it's able to break it...after that, the next culprit is the main shaft diameter...the strongest T56's have larger diameter output ends of the main shafts than the lower rated T56's...the strongest way to build one with OEM parts for example is an MM6 gear set from a 2006/2007 ZO6, and an SSR 32 spline main shaft. (takes some machining to cobble together)

Thanks...that was explained very well.

[Cuda7050]

Originally Posted by SP33D

MM6 w/ 3.91
1st gear ratio: 2.66 10.42
2nd gear ratio: 1.78 6.97
3rd gear ratio: 1.30 5.09
4th gear ratio: 1.00 3.91
5th gear ratio: 0.74 2.90
6th gear ratio: 0.50 1.96

M10 w/ 3.45 w/ 3.91
1st gear ratio: 3.01 10.38 11.77
2nd gear ratio: 2.07 7.14 8.09
3rd gear ratio: 1.43 4.93 5.59
4th gear ratio: 1.00 3.45 3.91
5th gear ratio: 0.84 2.90 3.28
6th gear ratio: 0.57 1.97 2.23

The key diference for road racing is the drop in RPM on each shift:

Assuming you shift at 6400 rpm the motor rpm will drop to these RPM's

MM6 w/3.91

1-2 shift rpm drops to 4,280
2-3 shift rpm drops to 4,673
3-4 shift rpm drops to 4,916

MM10 w/ 3.91

1-2 shift rpm drops to 4,398
2-3 shift rpm drops to 4,422
3-4 shift rpm drops to 4,476

The MM6 1LE trans keeps the motor in the upper rpm sweet spot between about 45 mph and 120 mph, but sacrafices some performance out of the hole in 1st gear (assuming full traction). Since 1/4 mile ET's are made in the first 60 feet, the MM10 is probably a faster drag race trans, assuming full traction.

[cbass]

By max speed in each gear:

Camaro SS:

1st: 54 mph
2nd: 79 mph
3rd: 114 mph
4th: 163 mph
5th: 194 mph
6th: 287 mph

Camaro 1LE:

1st: 53 mph
2nd: 79 mph
3rd: 108mph
4th: 140 mph
5th: 189 mph
6th: 280 mph

[Snidely Whiplash]

Originally Posted by blazzin1

Am I missing it somewhere on the first page, or is it buried somewhere within the other 46 pages???

Does this mean that our regular ol' M10 transmissions could start breaking stuff at around 430 ft-lbs. of torque???

You'll burn clutch discs and pressure plates before you hurt the transmission. Unless you've got over 550 lb-ft of torque and going to put on a set of drag radials for regular weekend fun, you're good to go.

If you're gonna drag race with that kind of power, the clutch and half-shafts need upgrading before the tranny. You can't break a transmission or other driveline parts with a slipping clutch.

Go out and have fun.

[Snidely Whiplash]

Originally Posted by Cuda7050

The key diference for road racing is the drop in RPM on each shift:

Assuming you shift at 6400 rpm the motor rpm will drop to these RPM's

MM6 w/3.91

1-2 shift rpm drops to 4,280
2-3 shift rpm drops to 4,673
3-4 shift rpm drops to 4,916

MM10 w/ 3.91

1-2 shift rpm drops to 4,398
2-3 shift rpm drops to 4,422
3-4 shift rpm drops to 4,476

The MM6 1LE trans keeps the motor in the upper rpm sweet spot between about 45 mph and 120 mph, but sacrafices some performance out of the hole in 1st gear (assuming full traction). Since 1/4 mile ET's are made in the first 60 feet, the MM10 is probably a faster drag race trans, assuming full traction.

Pure race cars in NHRA stock and super stock leave HARD and DO make their low ETs in the first 60'. Hence you get a and b class stock cars running high 10s - low 11s but only at 112 mph.

Assuming you're running drag radials or slicks. BIG difference with everyday drive tires in the first 60.

That doesn't count with turbo cars. The turbo doesn't start twisting and makin' bacon until AFTER 60 ft. That's why the 6 and 7 second small tire (10") cars are usually turbocharged.

[thunderkyss]

Does anyone want to beat a dead horse? I didn't realize the 1LE used a different transmission than the SS. I read something in another thread & started to investigate, so I found this thread. A lot of good stuff here & thought I'd add to it.

Originally Posted by Cuda7050

The key diference for road racing is the drop in RPM on each shift:

Assuming you shift at 6400 rpm the motor rpm will drop to these RPM's

MM6 w/3.91

1-2 shift rpm drops to 4,280
2-3 shift rpm drops to 4,673
3-4 shift rpm drops to 4,916

MM10 w/ 3.91

1-2 shift rpm drops to 4,398
2-3 shift rpm drops to 4,422
3-4 shift rpm drops to 4,476

The MM6 1LE trans keeps the motor in the upper rpm sweet spot between about 45 mph and 120 mph, but sacrafices some performance out of the hole in 1st gear (assuming full traction). Since 1/4 mile ET's are made in the first 60 feet, the MM10 is probably a faster drag race trans, assuming full traction.

Assuming you shift at 6400... However, max power is created at 5,900 for a stock motor. Improving the breathing (H/C/I) should raise that, so yes, that is conceivable. In the above example there isn't much difference in drop off through the first two shifts. You're still very close to your theoretical max torque. Close enough to do the job anyway.

Using the stock numbers though, the difference is more dramatic.



In second gear, both cars drop 600 rpm below max torque. But the shift to third, the MM6 car will be 300 rpm closer to stock max torque.

Switching to the 3.91 rear doesn't help this situation, other than you're going faster at the same RPM.

When I found out the 1LE had a bigger rear gear, like most I assumed it would run through the quarter faster, but it looks like (& this is my rudimentary high-school logic speaking here) the 1LE suffers with the smaller first gear, but makes up for it with the taller third.

Right?

Originally Posted by cbass

By max speed in each gear:

Camaro SS:

1st: 54 mph
2nd: 79 mph
3rd: 114 mph
4th: 163 mph
5th: 194 mph
6th: 287 mph

Camaro 1LE:

1st: 53 mph
2nd: 79 mph
3rd: 108mph
4th: 140 mph
5th: 189 mph
6th: 280 mph

I'd love to know the math behind this so I could add it to my chart to see what the difference is on the SS with a gear change.