Anyone know how much HP the stock trans can take if a supercharger is put on.

 

Well, as far as the late models, pretty sure the ZR1 is using the same M6 as the base/GS/Z06, so presume it'll hold 640 HP. Depending on what year/model you're talking' I'd say your rear end (diff, half-shafts) are the limiting factor. The above are all WAGs. YMMV.

 

I'm at 664whp and it's holding fine. The issue is if you want to hook up or not. I have the stock runflats and can't hook up for crap but my trans and diff are probably better off for it.

 

Nope. The ZR1 is beefier for what I've read. The Z06 could be the same as the GS (including the number of splines on the shafts); hopefully somebody can answer that. The clutch is supposedly the same... but again, the ZR1 has a beefier one.

What I know is my '12 has a weird 2nd gear synchro (side teeth) that is a POS, and reportedly causes the cold 'crunching'. Also read Tremec changed to that design on all trannies in either '12 or '13. Good luck.

 

Some digging around on the GM powertrain site shows:

MH3 trans-ZR1 (2009-2011) 650 max tq 1st-4th gears; 630tq 5th/6th gear.

ME2 trans -ZR1(2012-2013) same as above? / no info. Has slightly different 5th & 6th ratio

MM6 trans - (LS7/ZO6 version) 500 max / (LS3 version) 430 max tq

MZ6 trans (GS coupe/vert. LS3) 430 max tq.

MG9 (CTS-V/ LSA) 560 max tq

I plugged 2012 in for the search. Some of the LS3 models were at 425 max tq. for some earlier years.

Also see this for the different ratios:

http://gmpowertrain.com/Libraries/Pr...1111.sflb.ashx

 

My sincere apologies for posting incorrect information. As a newb, I should have known better. This forum is a wealth of information from very knowledgeable owners and enthusiasts, and I learn something every time I visit. I did a quick search and found this post by haljensen, one of the more informative posts regarding the differences between the various M6 and A6 trannys: http://forums.corvetteforum.com/1584004931-post2.html

What I didn't realize was that the lower ratios (higher numerically) are found in the GS's MZ6 box. When I bought my GS with MSRC, I was under the impression that it would be more of a track-oriented option, which in my uneducated mind would come with a close-ratio box. In reality, the first 3 gears have a wider numerical spread than even the base Vette, which to me suggests the gears were chosen for stop-light-to-stoplight acceleration and not track performance. If I had my 'druthers', I'd prefer the ratios available in the ZR1 box, which are the most closely spaced of the three M6 choices and should be more suitable for spirited backroads blasting.

From here on out, I promise I'll keep to posting about stuff I might know at least a little about and keep my WAGs to myself!

 

Actually, the wide ratio works well for both street and track. The wider ratio helps when accelerating out of turns (Z51 & GS). The closer ratio is more suitable for oval track racing. It will also depend on how much torque the engine puts out, more torque will require less low end gearing (ZR1).

I had an older Z28 with a close ratio M22 (2:20 first gear). Once moving, the close ratio gears kept you in the sweet spot. However, it did make my bottom end soggy with a bigger cam so in went a wide ratio. With wide ratio gears you need to make sure you do not shift too early from third to four or you can be out of that sweet spot. Keep in mind, it's also the spread difference % between gears that you need to know. On a wide ratio, the gear spread % might only be greater between 3r and 4th gears.

 

Like Mike above, I too came from the muscle car era. Our COPO Chevelle had the M20 wide ration Muncie and I loved it. When we bought the other '69 L78 car, it had the factory original M21 close ratio 4 speed. Even with the torque of the 396, the wide ratio was nicer for city driving. The close ratio transmissions were geared for road course running not stop and go. I had an M20 in the L78 car for a while when the M21 needed new bearings. Only for the sake or originality did I re-install the original M21. The M20 would be my choice. With our Corvette, I would like driving it more in stop and go driving if it had a lower first gear or something like 4.10s in the rear. With the deep overdrive of sixth gear, it still wouldn't be turning a lot of rpm at 70 mph and I doubt that gas mileage would suffer much if that is a consideration. With stock factory tires, you probably won't have enough traction to hurt much. With that much extra horsepower, just rolling into it in any of the first three gears will probably produce lost of tire smoke without even beating on it. Slicks and a dead hook in drag racing fashion will soon bring out any weak spots in the drivetrain.

 

Im well over 700RWHP in my 05 M6 and i am not having issues yet.

 

With the '05 like ours, the rear diff appears to the weak spot and the housing splits right in two when it lets go. Some ugly pictures on the internet. Still, it makes me feel better. Having less than half your power output shouldn't cause any problems.

 

Both the standard Corvette(without Z51) And the LS7/Z06 use the TR6060 MM6 transmission which is validated to 500 lb-ft torque.

http://corvetteactioncenter.com/spec...l#.UpnHT8Q_uI-
http://www.teamzr1.com/ubbthreads/ub...at&Number=3186

 

I used google & punched in the transmission models with GM Powertrain in the search, such as "GM Powertrain MM6". All the info I got was directly from GM data, not exterior websites. You can also type a year in the search to narrow it down. Do they use the MM6/ MGW, etc. codes only for gearset designations or for specific transmissions? I don't know. All I saw was GM data shows in a bunch of places that the MM6 trans appears to have 2 different torque rating depending on the application (LS7 vs. LS3). It seemed a bit odd to me at the time that they have one transmission with 2 different torque ratings which makes me wonder if the letter designations refer to gearsets. From there, do they use upgraded parts inside depending on the engine? The data clearly shows different torque rating though, unless I'm interpreting it wrong. I looked at quite a few data sheets at the time (I was working a 12 hour shift on Thanksgiving and had some free time to look), but here are a few to check out. I originally did this for each transmission designation, but the ones below are just for MM6. Some are Word or XLS. docs that are going to open in another window, but still directly from GM Powertrain.

Here is the info I got directly from GM powertrain from this link (2011). It's a word doc from GM:

http://gmpowertrain.com/PowertrainFi...0%20manual.doc

• Maximum engine torque rating of 430 lb.-ft. (580 Nm) – MM6 w/6.2L (LS3)
• Maximum gearbox torque rating of 430 lb.-ft. (580 Nm) – MM6 w/6.2L (LS3)
• Maximum engine torque rating of 470 lb.-ft. (637 Nm) – MM6 w/7.0L (LS7)
• Maximum gearbox torque rating of 500 lb.-ft. (678 Nm) – MM6 w/7.0L (LS7)

Here's another one directly from Gm Powertrain, its an XLS doc for 2012. There are 2 columns, one for each torque rating based on engine.

http://www.gmpowertrain.com/Powertra...060_MM6_n.xlsx

Also from Gm Powertrain (current website, have to go to powertrain products on right, transmissions in dropdown box, pick MM6) This is only good for current model year though:

Engine range: 6.2L gas (LS3) | 7.0L gas (LS7)
Maximum engine torque: 430 lb-ft ( 580 Nm ) | 470 lb-ft ( 637 Nm )
Maximum gearbox torque: 430 lb-ft ( 580 Nm ) | 500 lb-ft ( 678 Nm )
Gear ratios: MM6

 

You're right. It is odd.
Unfortunately, i couldn't get the links you provided to come up, wouldn't open.

I did check out the "GM Powertrain MM6" and found a couple links. One LINK shows One MM6 for Both Standard C6 and Z06 Corvettes rated at 500 lb-ft.TQ.
Other LINK shows info you provided with LS3/ MM6 at 430 lb-ft and MM6/ LS7 at 500 lb-ft.

Is it one MM6 for both cars rated at 500 TQ.? Or is there Two MM6 with two different Torque ratings used?
These links came from GM Powertrain MM6:
http://view.officeapps.live.com/op/v..._MG9_M10_n.doc

http://view.officeapps.live.com/op/v...2520manual.doc

Just noticed, info showing MM6 with two different TQ. rating is 2011-up.
Info showing One MM6 for both cars is 2010-down.

 

You'll probably snap the half shafts long before you damage the trans.

 

The 2011 word doc you show is one of the links I posted, so you found it. The other one was/is an Excel doc that pops up. Windows had an info bar ask if I wanted to open it, blah, blah, blah. That info is the same with 2 different torque ratings for the same MM6 designation. Even when trying to search for 2008, 2009 docs, they just aren't available in the XLS format and one of them kicks up to the 2010 Word doc. you have.

Anyhow, It is odd. Maybe there are upgraded components in the boxes & the letter designations refer to a gearsets? At any rate, Saplumr probably called it right, something else may break before the transmission does, .

Then again, I do have a stack of old broken Muncie M-20, 21, 22s & a Borg-Warner Super T-10 on the shelf with broken gears, & cases with the mounting ears all snapped off from the 'good old days'....



Edit: I found a Gm archive site that has a lot of the older data & spec sheets including the XLS pages. The first link is the general site with all the years. Then go to 'Powertrain', 'Car', etc. Once you get to the actual engine/transmission pages, click on the link (S, SS, WN) near the item you're looking for such as a specific engine or transmission. Good sites with a lot of info.

It looks like the earlier MM6 trans is rated at 470 torque for a 2008 with no distinction between base (6.0 L) or ZO6 (7.0 L).


http://archives.media.gm.com/us/gm/e...pig_index.html

http://archives.media.gm.com/us/powe...2008/08car.htm

http://archives.media.gm.com/us/powe...a/10car_us.htm

 

How is the diff?

 

I don't know for certain what the real deal is on the MM6 but it has made for good conversation.
Anyways, from what i have seen it appears GM used the same MM6 box (rated to 500 lb-ft) for the standard Vette and the Z06, at least for several years. Of course this Box would really benefit the standard Vette by virtue of its greater strength when used in "high stress situations".

"Old broken" Muncie M-20,21 and 22's?
That's all i used to deal with and ended up with some broken ones as well.
With Chevelles, i usually used the M-20 to get the car off the line. When it came to Camaros, Novas and V8 Vegas, i liked the close ratio trans better to keep the motor in its "sweet spot".

Thanks for the links, some good reading!

EDIT: May have found the answer on the MM6.

"When the high-performance Z06 version of the Corvette was introduced for 2006, a stronger single-piece countershaft replaced the previous two-piece countershaft for the MM6. The output shaft was enlarged to a 30-spline unit, which is more durable than the 27-spline unit used in previous applications".

 

U can sorta throw what u want a a stock 6 speed manual transmission. .weak point is output shafts but besides that..The tranny are strong..When they go out most of the time it's because of basically the stuff in side tranny that makes it Go to the gear,and stay in gear..which would be fork, blocker rings,syncro,pads.. but if u don't plan on drag racing and it's shifting fine throw whatever u want at it

 

will a base model ls3 Tr6060 manual transmission fit a ls7 z06 (08-13)?

 

I'm pretty sure the Z06/GS has a 30 spline output shaft and the base has 27 splines. The GS has lower ratios though which makes it not as strong as the Z06