[Jonjt]

Originally Posted by Evan135

I am speaking in round numbers here so please do not flame me. The M4 is supposed to have the weight of the E46 M3. Current M3 around 3700 pounds and E46 M3 around 3450. The 250 pound weight loss is supposed to come from light weight subframes for the front and rear.

I think I heard the subframes will be out of aluminum which would improve chassis stiffness, and with the usual M suspension components in aluminum and maybe a few light weight body parts.

The current N20 weighs around 150 pounds less than the N55 and is shorter improving weight distribution. The M2 is supposed to use the 1M recipe of stuffing the M3 subframes and suspension right into the M2.

With 400 pounds(250 from subframes and 150 from the engine) gone from the 1M it is very possible to see a 3000 pound or less M2 with much better weight distribution and lower polar moment, all great for responsive handling.

I love that the inline six is so smooth and well balanced that it does not require balance shafts with there added weight that effect engine responsiveness, though BMW does it with lower weight than most. So I do like the idea of an M2 with an inline 6.

But with the right 4 cylinder at around 350 hp, 3000 pounds of weight, and better weight distribution, this may be the most fun street M BMW has made.

An aluminum subframe would be significantly less stiff than a steel one of an otherwise identical design. The steels available to the auto industry for chassis design are far stiffer and far stronger than the available aluminum alloys. Just an fyi.

[Antares]

Originally Posted by pkim1079

so the m235i will have 6 and the m2 will have 4? that is just retarded.

Originally Posted by Evan135

from light weight subframes for the front and rear.
I think I heard the subframes will be out of aluminum which would improve chassis stiffness, and with the usual M suspension components in aluminum and maybe a few light weight body parts.

Technology and road-legends are two different things.
USA have a historic love for big displacement engines and V6, V8, V12 stickers. Only in USA it was possible to sell a sports car with a truck engine inside-Viper.

European market and mentality is more about engineering. You can make wonders with aggressive turbocharged engines. The engine is more responsive (less rotating mass), it easily operates in high revolutions/minute mode, it consumes less fuel.
Above all, one and same engine can present various operating modes; one car-multiple engines.
By turning a switch you can go from a performance sports cars that consumes lots of fuel, to a calm fuel efficient car that can be used for every day needs.

Modern automotive steels are far above aluminum; certain very expensive cars used aluminum since the boutique manufacturer did not have access to modern steel. Aluminum is also difficult to repair. Besides, a BMW feels solid even after long years of use; something aluminium does not guarantee.

[GeeRam]

Originally Posted by Remonster

Will it really have a DCT? The M135i has the 8 speed sport auto.

Yup, M135 has the 8 speed ZF auto option. I fully expect the M235 to be in line with that, leaving DCT for the 'full fat' ///M range.

[Jonjt]

Originally Posted by Antares

Technology and road-legends are two different things.
USA have a historic love for big displacement engines and V6, V8, V12 stickers. Only in USA it was possible to sell a sports car with a truck engine inside-Viper.

European market and mentality is more about engineering. You can make wonders with aggressive turbocharged engines. The engine is more responsive (less rotating mass), it easily operates in high revolutions/minute mode, it consumes less fuel.
Above all, one and same engine can present various operating modes; one car-multiple engines.
By turning a switch you can go from a performance sports cars that consumes lots of fuel, to a calm fuel efficient car that can be used for every day needs.

Modern automotive steels are far above aluminum; certain very expensive cars used aluminum since the boutique manufacturer did not have access to modern steel. Aluminum is also difficult to repair. Besides, a BMW feels solid even after long years of use; something aluminium does not guarantee.

The boutique manufacturers do have access to modern steels. They usually choose (chose) to go with aluminum because of the lower weight. Other than the lower weight per unit volume and the better corrosion resistance, aluminum doesn't have any advantages over steel, for this application.

You're right about the fatigue behavior, though. You aren't going to see any aluminum chassis cars on the road for 50+ years, since the strength of aluminum tends to decrease over time, no matter the loads. Below a certain threshold, steels don't have this problem.

Carbon composites are even better than steels in the fatigue department. if you can keep the laminations protected, you can get away with way higher levels of stress for longer periods. It's going to be a great thing, having carbon composite chassis cars. Just don't crash them………

[Jonjt]

I was sitting at my desk and I realized:
If the M2 really is a turbo 4, it's gonna sound awful………

[HoundForHire]

Originally Posted by GeeRam

Yup, M135 has the 8 speed ZF auto option. I fully expect the M235 to be in line with that, leaving DCT for the 'full fat' ///M range.

That bugs me. I didn't like the ZF's performance in the F30 335i i tested...is it different in the Msport config?

The current US spec 2013/12 135i has a DCT... why not keep it? At least as a option, kind a must have for me.

[bradleyland]

Originally Posted by HoundForHire

That bugs me. I didn't like the ZF's performance in the F30 335i i tested...is it different in the Msport config?

The current US spec 2013/12 135i has a DCT... why not keep it? At least as a option, kind a must have for me.

I'm with you on this one. Then again, I owned one dual-clutch gearbox, and I missed my third pedal too much, so I went back to a manual.

Maybe I'm better off staying out of this discussion

[HoundForHire]

well i've have some physical things going on that just makes driving an auto a lot easier/less painful. Plus, I love the feel of the DCT shifting and the paddle downshifts. Pure joy.

I get that the M135i current doesn't have it, but I really hope BMW gives the US market the option for it.

[BMW269]

To say the truth if BMW give the M2 an I4, it will be a better car than if they give it an I6. How do I support my theory? Without facts, but very a precise deduction:

- If BMW gives the M2 the engine of the M4, even detuned, performance wise it will be to close to the M4, if not ahead. Already now the E82M with 340 PS was nearly as fast as the E92M with 420 PS.
- If BMW gives the M2 just a tuned version of the engine found in the M135i, the M2 will not be a "true" M-Car (ready difficult to define what a true M-Car is nowadays).
- A slightly tuned engine from the M135i will be more cost reductive, than a newly developed I4 by M Gmbh (i.e. N55 (M135i) vs. S55 (M4)).

To conclude, BMW not being able to give the M2 the engine from the M4, as it would just be too good, (think Cayman vs. 911), they'll have to go with a cheap I6 or an expensive I4. BMW prefers the cheaper way, this was shown with to choice of the cheaper I6 vs. the more expensive V6 for the M3/M4, but maybe BMW decided to spend the saved money on a better I4 for the M2.

Fact is, if the M2 gets an I4, it will be a better can than if it gets an I6, because it will cost more and we know they want to reduce costs.

You may think, that if an M4 can have an I6, then the M2 based on M4 can also get that engine, but it will affect balance. The new I6 of the M4 will be as heavy, if not heavier than the V8 of the M3, but it will be longer, so worse. In current comparission between 328i and 335i, reviewers said the 328i has bettter balance than 335i. This is even more relevant for the M2, which has a shorter wheelbase. Moreover, the addtional power of an I6 will not be important for the M2, regardless of taking shares from the M4, because the M2 will overall be lighter, even without extended use of CF.


M2 with I4 FTW!!!

[GeeRam]

Originally Posted by HoundForHire

well i've have some physical things going on that just makes driving an auto a lot easier/less painful. Plus, I love the feel of the DCT shifting and the paddle downshifts. Pure joy.

I get that the M135i current doesn't have it, but I really hope BMW gives the US market the option for it.

I can't see BMW re-engineering the car for DCT just for the USA market.

As a 135i DCT owner, I agree, I'm not sure I like the idea of going back to a conventional auto.
The M135 auto owners I've talked to here in the UK have said the 8-speed ZF in the M135 is very good, and you'd swear it was a DCT

I'm sure I've read that the DCT technology will be exclusive to the full ///M cars from now on as another means of differentiating them from the 'lesser' Mprefix cars.

I'm going to try and blag a drive of a M135 auto soon to see what it's like, but I might well hang onto my current 135i longer than planned rather than go back to a conventional auto again.

[HoundForHire]

Originally Posted by GeeRam

The M135 auto owners I've talked to here in the UK have said the 8-speed ZF in the M135 is very good, and you'd swear it was a DCT

I'm going to try and blag a drive of a M135 auto soon to see what it's like, but I might well hang onto my current 135i longer than planned rather than go back to a conventional auto again.

I've read that too, I just was dissapointed with the unit in the F30 I tested. That being said, it wasn't MSport. I'll go check out a Msport unit this weekend.

If the DCT isn't for non-M cars anymore, I'll be looking for a used E82 1er in a few years...

[BMW269]

Originally Posted by Jonjt

I was sitting at my desk and I realized:
If the M2 really is a turbo 4, it's gonna sound awful………

Not necesseraly.

[Evan135]

Originally Posted by Jonjt

An aluminum subframe would be significantly less stiff than a steel one of an otherwise identical design. The steels available to the auto industry for chassis design are far stiffer and far stronger than the available aluminum alloys. Just an fyi.

I appreciate your input but do a little research of young's modulus for different steels and different aluminums with respect to mass and strength. You can correctly design aluminum that is stiffer and lighter the high strength steel. If you could not, no one would use any aluminum as it typically would be more expensive.

The younds modulus for typical aluminum is 10 million psi and steels modulus is 30 million psi. The weight of aluminum is about .1 pound per cubic inch and steel is about .3 pounds per cubic inch. Hence they appear to be relatively equal from a strenth to weight evaluation.

But the reports are that BMW is using aluminum and as I said you can design an alumium structure liughter and stiffer than steel. It is all about the material and how the design uses it. The correct application.

Regardless of the execution on the materials BMW has been reported to be using aluminum to stiffen and reduce weight on the next M3/m4 subframes. The weight loss has not been reported so far to be from light weight carbon fiber plastic composites but the subframes.

[Remonster]

Originally Posted by Jonjt

An aluminum subframe would be significantly less stiff than a steel one of an otherwise identical design. The steels available to the auto industry for chassis design are far stiffer and far stronger than the available aluminum alloys. Just an fyi.

Think about this, M gmbh took the BMW E90 platform and decided to throw out its rear subframe and engineer an entirely new aluminum one. Do you think they would have gone through that trouble if the end result wasn't much, much better than sticking with steel?

Weight saving wasn't their only design goal, does the rear end of the E9x M3 feel loose and floppy to you? Aluminum can be plenty stiff when designed properly and used in appropriate quantities.

[Antares]

Originally Posted by Jonjt

The boutique manufacturers do have access to modern steels.

I admit, I just wanted to put aluminium on the side track to quickly, since I did not want to go into a discussion of the whole machinery investment, produced volume, process requirements in regards to aluminium/modern steel.
Aluminum is really lighter, but even more exotic to advertise.

[pinemind]

What are we looking at in terms of dimensions here? I'm asking mainly because the 1 series had an unusable backseat. If this 2 series coupe is slightly bigger and can handle reasonable adults in the back, this could be my next car. The e92 is perfect for 2 adults in the back and the F30/F32 are growing too large for my tastes. So if it's between an e90 and 1 series, it could hit a sweet spot.

[Jonjt]

Originally Posted by Evan135

......

You don't understand the characteristics of the aluminum and steel alloys that are available to the auto industry. Or, I should say, you don't understand why materials are chosen for specific purposes, and how those purposes influence the design process. And, you need to do a bit of research to understand exactly what stiffness and strength are, with respect to engineering materials. You're confusing them.

You can correctly design aluminum that is stiffer and lighter the high strength steel. If you could not, no one would use any aluminum as it typically would be more expensive.

The idea that an aluminum part will always be strong and lighter than a steel part is incorrect. Available steels are stronger, stiffer and have higher ultimate and rupture strengths, better fatigue properties, etc. Making the jump from the material properties to a well designed part is tenuous, because design criteria, resources, goals, etc, play a huge part in why certain materials are chosen. However, suffice to say that one cannot just assume that aluminum parts are always going to be stiffer and lighter.

The younds modulus for typical aluminum is 10 million psi and steels modulus is 30 million psi. The weight of aluminum is about .1 pound per cubic inch and steel is about .3 pounds per cubic inch. Hence they appear to be relatively equal from a strenth to weight evaluation.

No. You are talking about STIFFNESS per unit weight, not strength. In material property terms, there are many different "types" of strength, the definition of which depend on how you are defining material failure. Wikipedia has a good article on this.

But the reports are that BMW is using aluminum and as I said you can design an alumium structure liughter and stiffer than steel. It is all about the material and how the design uses it. The correct application.

Again, "can" does not mean "always". As you acknowledged, it depends on the design. Usually, in this regard, one characteristic is optimized, while the other is not. It's very rare that a designer can replace a steel part with an identical aluminum one that is lighter and stiffer. Usually, when that happens, it's a consequence of a poor previous design and/or improvements in design and manufacturing technology. To use a more equal comparison, if you were to design optimized parts, one aluminum and one steel, for the same application, at the same time, to the best of your engineering ability, the steel part will be STIFFER and STRONGER but the aluminum one will be LIGHTER.

Regardless of the execution on the materials BMW has been reported to be using aluminum to stiffen and reduce weight on the next M3/m4 subframes. The weight loss has not been reported so far to be from light weight carbon fiber plastic composites but the subframes.

You're making some serious assumptions about the particulars of the design of the subframes, without knowing anything about them except that BMW is using aluminum. Worse yet, you're comparing subframes from two different generations of BMW cars! There are so many ways to make a subframe for one car lighter and stiffer than a subframe from another, when the two cars are of a different design! The newer car could have a physically smaller subframe, it could be redesigned to be more rigid in torsion, bending, compression, tension, or any other complex loading condition, etc. Saying that the subframe is lighter AND stronger just because it's aluminum is myopic, at best and just downright wrong, at worst.

BMW's marketing department, maybe, or an insider has leaked this information just to pique interest. No one is going to release a full design brief on the subframes, unfortunately. And, that would be needed to fully understand HOW BMW is making the subframes lighter and stiffer. Saying it's just because they switched to aluminum, when aluminum is no where near as stiff, as strong or as fatigue resistant as steel, is just wrong.

[Jonjt]

Originally Posted by Remonster

Think about this, M gmbh took the BMW E90 platform and decided to throw out its rear subframe and engineer an entirely new aluminum one. Do you think they would have gone through that trouble if the end result wasn't much, much better than sticking with steel?

Weight saving wasn't their only design goal, does the rear end of the E9x M3 feel loose and floppy to you? Aluminum can be plenty stiff when designed properly and used in appropriate quantities.

As I responded to Evan, I will respond to you. There is much more that goes into the creation of a subframe than choosing the material. We are talking about two different cars here, with many variables to tweak, besides the material they are using. BMW most likely did not just change the material, they probably designed a subframe that is of a different geometry, in addition to being of a different material. The combination of the two things is what produced a lighter and stiffer subframe.

As for the M3, that chassis is far superior to the non M 3 series. But, it's because BMW choose to redesign the entire subframe. It's of a different geometry, it's of a different material (IIRC) AND, its because BMW choose to use different bushings and bearings to carry the load. You are so incredibly oversimplifying the car design process by saying that the upcoming M2/M3/M4 have lighter/stiffer/better subframes just because it's made from aluminum.

[Jonjt]

Originally Posted by Antares

I admit, I just wanted to put aluminium on the side track to quickly, since I did not want to go into a discussion of the whole machinery investment, produced volume, process requirements in regards to aluminium/modern steel.
Aluminum is really lighter, but even more exotic to advertise.

You get it. They fell for it.

[Remonster]

Originally Posted by Jonjt

As I responded to Evan, I will respond to you. There is much more that goes into the creation of a subframe than choosing the material. We are talking about two different cars here, with many variables to tweak, besides the material they are using. BMW most likely did not just change the material, they probably designed a subframe that is of a different geometry, in addition to being of a different material. The combination of the two things is what produced a lighter and stiffer subframe.

As for the M3, that chassis is far superior to the non M 3 series. But, it's because BMW choose to redesign the entire subframe. It's of a different geometry, it's of a different material (IIRC) AND, its because BMW choose to use different bushings and bearings to carry the load. You are so incredibly oversimplifying the car design process by saying that the upcoming M2/M3/M4 have lighter/stiffer/better subframes just because it's made from aluminum.

Wait, that's what I was trying to argue to you...I guess I misread what you wrote. I thought you were trying to say "aluminum will always be less stiff," and my point was that they obviously designed the subframe differently to get around aluminum's inherent softness but it seems that we're on the same page.

[Antares]

Originally Posted by Jonjt

You get it. They fell for it.

Appearance is all

You would hardly believe what various gurus of healthy eating manage to sell to the populace.
Few biochemistry principles of human metabolism were extended to thousands of pages, that fill thousands of books. The "healthy eating" gurus that accuse the food industry are themselves an industry (of words, books and "bio" products) and prime manipulators.

Considering what people send down their blessed throats, I think that this aluminium discussion is really of no big worry.
Imagine if someone would begin to advertise chassis parts in titanium! Or even better vanadium!


For me personally the best car would be a combination of modern high strength steel and carbon fibers.
Regretfully the costs are going to be prohibitive for the next 20 years.

[Jonjt]

Originally Posted by Remonster

Wait, that's what I was trying to argue to you...I guess I misread what you wrote. I thought you were trying to say "aluminum will always be less stiff," and my point was that they obviously designed the subframe differently to get around aluminum's inherent softness but it seems that we're on the same page.

Gotcha. We are in agreement then.