Building a Stronger 6-spd Man Trans

[theenico]

theenico has arrived with valuable info. But I'm still hungry for moe.

The Cruze MZ0 is a direct swap, correct? I remember hearing somewhere that it's rated for slightly more hp/tq than the M32. If so, I may start seeking one out for an overhaul and shot-peen.

Also, what are the ratios on the MZ0?

Yes, MZ0 is a direct swap.

The ratios for most of the M32s are in my ratio thread: http://www.sonicownersforum.com/forum/t725/

For more ratios, "rated" torque capacity, and vehicle applications; go to: Powertrain Products

The 1st gears are rated for lower torques than 2nd through 6th in all the M32s. If there's a large difference in tooth count between the driving and driven gears, it will be weaker. For example, a 4.27:1 will be weaker than a 3.82:1.

Per the second link above, the 1st gear in the MZ0 and MZ4 is rated for 260Nm (192ft/lbs) whereas the MR5 (RS) 1st gear is only rated for 230Nm (170ft/lbs).

Edit because of engine torque rating differences between the NA and European M32s with the same RPO.

MZ0 and MZ4:
North America = 170Nm (125ft/lbs) max engine torque and 320Nm (236ft/lbs) max gearbox torque.
Europe = 300Nm (221ft/lbs) max engine torque and 320Nm (236ft/lbs) max gearbox torque.

MR5:
North America = 200Nm (148ft/lbs) max engine torque and 320Nm (236ft/lbs) max gearbox torque.
Europe = 280Nm (207ft/lbs) max engine torque and 320Nm (236ft/lbs) max gearbox torque.

Something is odd with the NA engine torques. They seem way too low and I kind of wonder if it doesn't have to do with the thinner oil they spec'ed for us over here.

 

[Preloader]

Good to know.

I spoke to my Pops, and he concurred that shot preening the gears is the best thing to do for added strength.

As far as autos go, he said a better clutch disc is desirable. He said you can even add an extra friction disc if you get thinner steels. The stock clutch discs will burn up when they are pushed too far.

My next move is to start hunting for a salvaged MZ0 for tear down and shot peen.

 

[theenico]

Good to know.

I spoke to my Pops, and he concurred that shot preening the gears is the best thing to do for added strength.

As far as autos go, he said a better clutch disc is desirable. He said you can even add an extra friction disc if you get thinner steels. The stock clutch discs will burn up when they are pushed too far.

My next move is to start hunting for a salvaged MZ0 for tear down and shot peen.

I just wanted to quote and add emphasis so people don't get confused about the clutch disc thing since auto and manual clutches are totally different animals.

Finding an MZ0 shouldn't be too hard. There have been two full years of production thanks to the Cruze.

(I got to use all three versions of "to" in that last section )

Check my last edit in my prior post. More info added.

 

[Preloader]

This is by far the most exciting project going into my build so far. There are so many developments coming down the pipeline to increase power/torque, but none of it means jack if the trans can't handle and deliver it to the wheels.

My goal is to research (which is free as always) and build a trans with enough headroom so I can can balls out on power later without having to revisit the trans.

I absolutely plan to start with an MZ0, and I am pleased to know that they won't be impossible to find.

For what it's worth, I believe just a stock MZ0 swap alone should get at least a tenth off the qtr based on the gearing.

 

[River_Rat]

I already know theenico's opinion on the matter from the F40 swap thread

To answer the original question, the F40 and M32 are different transmission families. The F40 is physically larger. It may bolt to the engine (probably not though since the M32 is used with family 0 and 1 engines, whereas the F40 is used on family 2 and larger engines). If it did bolt up you would still have to fabricate mounts, adapt the shift cables, figure out the clutch, deal with the VSS, and get custom axles. Not really a swap for the faint of heart.

If you're worried about the M32 strength, it would probably be more cost effective to shot peen, REM finish, and cryogenically treat the gears and shafts.

But has it been conclusively determined that the F40 will not physically mate to the 1.4? I know it wouldn't be cheap or easy, but in the end I think you would end up with a much better product. Metal treatments and hardening can only go so far. I'm just not convinced there is any treatment that can be done to the M32 that will keep up with the potential torque output of the 1.4 with a turbo upgrade. The treatments are only cost effective until you grenade the transmission and have to start over.

I guess it depends on just how far you want to go with power mods for the 1.4. Stock 2.0T power levels are not out of the question, so it makes sense to try and swap, if at all possible, a transmission designed for those levels.

 

[ThatTmoGuy]

If you want to do something insane with it you could shorten up all the gears a bit to get some extra strength. A shorter gear has less teeth so it has more surface area on each tooth. You would need to beef up the final drive gear and maybe make it a bit taller tom compensate for the shortened driving gears.

 

[$ub$onic]

There's a point where to big of a gear has the opposite effect

 

[theenico]

...has it been conclusively determined that the F40 will not physically mate to the 1.4?

It has not.

If someone has an F40 and a family 0/1 engine block laying around, maybe they'll see this and can tell us for sure.

Here are some pictures of the bell housings. It's the best I can come up with on a quick image search.

M32:

F40:

From the pictures, the starter position is definitely different, and the bolt pattern appears to be different also.

 

[firstorbit84]

so what's the maximum power that the M 32 can hold?

 

[Preloader]

Adapter plate?

I'm sure one of our supporting vendors could whip something up. Is there a way to tell if the input splines are the same?

 

[$ub$onic]

Or go to your local fab shop and they can whip it up to

 

[theenico]

Or go to your local fab shop and they can whip it up to...

...the tune of $1,000 plus dollars (I was one of those shops several years ago). Then you have to figure out the clutch which will be a one off since you added 1/2" or more of adapter plate (regardless of the input splines) add another grand. Of course there's also the fab work to adapt axles, mounts, shifter, etc.

I think I'll work on upgrading the M32, thanks.

 

[$ub$onic]

Must be nice to have a family member in the businesses then

 

[redsonic]

You could also upgrade synchros and grind the dogs on the gears to ensure a positive engagement everytime and the clutch is a big factor in keeping your trans together . Also an lsd would be an upgrade too keep the trans together off topic I blew 6 diffs in two different saturns in one year ended up blowing the case out three times not fun I dont think we will be making enough power to have to cryo the gears my father has been building transmissions for 35 years and hes built manuals with factory gears not frozen with heavy duty synchros and the right fluid that last l8ng with high horse motors ie 500 or better also the only thing with autos is heat its there number one enemy and ignorant drivers too haha

 

[theenico]

Must be nice to have a family member in the businesses then

Indeed. Given the proper allocation of resources (time, money, etc.), you can build whatever the imagination can conjure.

 

[$ub$onic]

And I have.. .

 

[Preloader]

Found a used (7k) MZO in Alabama, for $700. Tempting, but I'm gonna hunt for a better deal first.

 

[Dragcamaro]

went and looked at the gm powertrain site and compared the MR5 and MZ0, its odd how the 1st/reverse torque rating is lower for the MR5(larger gear, smaller teeth as has been discussed) but the maximum engine torque is higher at 200nm vs 170.

just a thought

 

[Dragcamaro]

i guess thats just 1.8 vs 1.4 ratings

 

[Eric Smit]

power is power, it doesn't matter what engine is attached to it.


-Eric Smit