F40 versus M32 Transmission

[Nikkro]

Looking for confirmation or counter evidence to the relationship between the M32 in the sonic and some Opels and the F40 used for the LTG in transverse form. It appears that GM in their infinite laziness may have lowered the tolerances of a F40 to make the weaker M32.

This is important for one reason; there is an Opel (Astra J OPC) I believe has been misidentified. Wikipedia lists it using an A20NHT but the specs for the output and emissions match the 2.0T LTG perfectly. If this car used the LTG and an F40 (confirmed the F40), it may be a valid option for a swap with less custom work for mounts.

Main evidence;
The same car in lower trim levels uses our M32 and is (I think?) the source of our LSD options.
The engine specifications (including the g co2/year don't match the A20NHT.
The F40 is the transmission used with the LTG in transverse applications.
The M32 isn't listed with GM's normal transmissions and appears to exist in a weird middle classification.
The F40 and M32 share the three shaft design, gear ratios, and other similarities.

I'm not completely attached to this idea but I would like to know. The LS3 Sonic Rally car makes me want to get some specs together.

 

[Vicarious]

I can't comment on it from a Sonic's perspective, but I've got quite a lot of experience with the F40 - it's how you give a Fiero a six-speed:

One possible issue you may run in to (Not sure here) is that the F40 is a physically big transmission, you might not be able to cram it in without moving absolutely everything alongside it. With the Fiero it's not so bad, because there's no steering rack, brake and clutch cylinders, brake booster and many other things, so there's oodles of space. I suspect the Sonic may be a bit more of a tighter squeeze.

I'd also personally argue that it's overkill for the Sonic, the thing is built to take the power out of turbo fives and V6s, though that's more of a personal thing. The M32 is already built to handle 320Nm (235 ft-lbs). Going to the heavier, bigger F40 just to get that extra little bit (400Nm/300ft-lbs) might not be worth it.

 

[skurtov]

I can't comment on it from a Sonic's perspective, but I've got quite a lot of experience with the F40 - it's how you give a Fiero a six-speed:

One possible issue you may run in to (Not sure here) is that the F40 is a physically big transmission, you might not be able to cram it in without moving absolutely everything alongside it. With the Fiero it's not so bad, because there's no steering rack, brake and clutch cylinders, brake booster and many other things, so there's oodles of space. I suspect the Sonic may be a bit more of a tighter squeeze.

I'd also personally argue that it's overkill for the Sonic, the thing is built to take the power out of turbo fives and V6s, though that's more of a personal thing. The M32 is already built to handle 320Nm (235 ft-lbs). Going to the heavier, bigger F40 just to get that extra little bit (400Nm/300ft-lbs) might not be worth it.

It's not overkill considering how common, and systemic the M32 bearing failures are. There was talk on the Vauxhall forums about swapping in F40's to have a more reliable transmission but I think it requires a custom driveshaft and something to adapt the factory mounts.

Long story short. Search through the Vauxhall forums if you want more. The topic has been discussed since those guys have had the M32 in a bunch of different models.

 

[Nikkro]

The M32 is already built to handle 320Nm (235 ft-lbs). Going to the heavier, bigger F40 just to get that extra little bit (400Nm/300ft-lbs) might not be worth it.

I want to build an LTG powered Sonic down the road, and 300 lb/ft of torque would shred the M32.

It's not overkill considering how common, and systemic the M32 bearing failures are. There was talk on the Vauxhall forums about swapping in F40's to have a more reliable transmission but I think it requires a custom driveshaft and something to adapt the factory mounts.

Long story short. Search through the Vauxhall forums if you want more. The topic has been discussed since those guys have had the M32 in a bunch of different models.

Considering the amount of custom work I am thinking of signing up for, I would love to see someone else's mistakes so I can make new ones instead. Thanks, I'll check the Vauxhall site!