Build quality of base models vs M models

[Parise2713]

Basically like the title says, I've been wondering about that for a while. Not really sure how they would line up. I just figured that the M would need to built a little bit better as far as parts go to ensure the performance that is expected from the car. I've been driving my 35i pretty hard the past few months and I've been a little worried about breaking parts on it. Just had the transmission replaced a few months ago and am worried about damaging this one. Does anyone know if the transmission and other parts are build any differently in an M model vs the other models? Not sure if I'm asking this very clearly but I'm not quite sure how to.

[omgboost]

How are you launching the car? Any mods in your car?

[JupiterBMW]

I don't think the build "quality" is any better. Typically, some parts are of better design to provide better performance, but I think they're all assembled with the same level of skill/quality. I'm just speculating on all of this, but hopefully this helps. For instance, the cooling system in the M is supposedly more robust, but I'm sure its still the same mix of plastic and metal parts... And the M had the recall a few years back for one of the water pumps...

[Crazy1323]

I believe the entire drivetrain is unique to the M (engine, transmission, and rear diff)

I know the suspension parts numbers are different, but I believe the mounting points are the same. This makes me think the body is the same.

[Parise2713]

Originally Posted by omgboost

How are you launching the car? Any mods in your car?

Nothing that would really affect the car. An exhaust cut out is really the only mod other than little exterior stuff. Not tuned or anything yet. I was being stupid with it and feel like I just drive it a little hard. A few months ago I was trying to drift it around in the snow, let's just say that didn't work out too well. The car is a 2012 with 82k miles on it. Probably not the best call to abuse it too much.

[Parise2713]

Originally Posted by JupiterBMW

I don't think the build "quality" is any better. Typically, some parts are of better design to provide better performance, but I think they're all assembled with the same level of skill/quality. I'm just speculating on all of this, but hopefully this helps. For instance, the cooling system in the M is supposedly more robust, but I'm sure its still the same mix of plastic and metal parts... And the M had the recall a few years back for one of the water pumps...

Yeah it does, thanks for the input. Yeah I'm not really sure what I'm trying to ask. I agree with you that it's probably all of the same metals and plastics used. Don't think they would go out of their way to use all different materials. Guess more specially i was just wondering about the tranny. I just feel like the stock base isn't suppose to be driven like an m would be. What your saying totally makes sense though. Thanks for replying!

[Parise2713]

Originally Posted by Crazy1323

I believe the entire drivetrain is unique to the M (engine, transmission, and rear diff)

I know the suspension parts numbers are different, but I believe the mounting points are the same. This makes me think the body is the same.

Yeah that's what I've been leaning towards. So it seems like we all agree that the materials and the bodies are the same but how they are technical configured might be different?

[omgboost]

I know that the 35i transmission is only rated to handle max torque of 332 ft-lbs. The 50i and M will have different max ratings. The transmissions are all sourced from ZF.

[smyles]

The only difference b/w M and 'regular' 6-speed ZF tranny is electronics to allow faster shifts.
The body is exactly the same, no special treatment.
Engine, suspension, brakes, subframe mount elements are unique to M.

[Parise2713]

Oh okay, thanks. Wasn't too sure about this. Knew you guys would know way more than I did. Thanks

[FSociety]

Originally Posted by omgboost

I know that the 35i transmission is only rated to handle max torque of 332 ft-lbs. The 50i and M will have different max ratings. The transmissions are all sourced from ZF.

There's a huge discussion going on btwn the 28i (N20) and 35i (N55) transmission handling beyond 330 tq.. The N20 has misfires beyond 330-350 range but the 35i is doing 400tq just fine.

So it looks even the trans on the 35 is able to handle more than the 28i trans even though they're similar in name.

[Crazy1323]

I know the rear axles are different because the M uses a small hub bore size in the rear whereas the standard models use the same size front and rear.

[smyles]

It's because they are from X6.