Why no CFRP trunk lid on M3?

[Sedan_Clan]

Originally Posted by GregW / Oregon

I know this is all personal opinion, but I don't know how anyone could say the greenhouse on the sedan is better than the coupe's (see link).

http://f80.bimmerpost.com/forums/sho...2&postcount=72

*raises hand*


I prefer the sedan's profile. With the E9X cars I preferred the coupe.

[sameh]

Aside from aerodynamic design and weight saving, I read that the trunk lid actually opens when you push the button on key fob which I attributed to lighter weight. So does this mean F80 trunk lid will just unlock but stays down like on E92?
I know it's a trivial issue but my 9 years old daughter really struggles with the current weight of my E92 trunk lid.

[ozinaldo]

Originally Posted by GregW / Oregon

I know this is all personal opinion, but I don't know how anyone could say the greenhouse on the sedan is better than the coupe's (see link).

http://f80.bimmerpost.com/forums/sho...2&postcount=72

Exactly as you said, it is personal and I sincerely find all rear half of the coupe longer than I would like it to be, too long! Which makes the car looks like as if it is much longer than the sedan (they have the same length) and kind of heavier at the rear. The coupe roof line is sure elegant as always but I can't single it out since it is just one part of the whole shape and I prefer the more balanced/proportional/classical BMW design of the F80. As an owner of a 1M, the flared arches helps too.

I found the new M4 almost like a fastback or liftback profile, hard to explain; it is probably not that obvious and much better looking in real life but from all the photos I've seen that's my impression. So the trunk lid is indeed the only "dull" part of the F80 design for me...and lack of a loveable exterior color.

[GregW / Oregon]

Originally Posted by ozinaldo

Exactly as you said, it is personal and I sincerely find all rear half of the coupe longer than I would like it to be, too long! Which makes the car looks like as if it is much longer than the sedan (they have the same length) and kind of heavier at the rear. The coupe roof line is sure elegant as always but I can't single it out since it is just one part of the whole shape and I prefer the more balanced/proportional/classical BMW design of the F80. As an owner of a 1M, the flared arches helps too.

I found the new M4 almost like a fastback or liftback profile, hard to explain; it is probably not that obvious and much better looking in real life but from all the photos I've seen that's my impression. So the trunk lid is indeed the only "dull" part of the F80 design for me...and lack of a loveable exterior color.

Fair enough. Too bad the sedan can't be done with frameless door glass like the coupe, though, because that is much better IMO than the heavy sedan exposed B pillar.

[swamp2]

Originally Posted by Technic

To me, the decision of the CFRP trunk in the M4 vs. the M3 was done just to separate the M4 from the M3 further in price and image. They may say that it was for aero reasons but then we have a significant weight reduction as well.

So perhaps the M3 did not need any aero improvements in the trunk but then again, less weight is a also benefit by itself.

Originally Posted by CanAutM3

My guess on the decision process: the M4 trunk needs redesign to improve the aero charateristics, so might as well take the opportunity to make it out of CFRP. The M3 trunk works just fine, let's keep it as-is. It's a question of selecting where to invest limited R&D funds and resources.

Two reasonable POVs on the surface. But note, R&D is never really the driving factor about what makes it into production and what doesn't. Part costs typically dwarfs R&D costs. The CF trunk is substantially more expensive than its steel counterpart both due to the raw material cost and the relatively low volume. It only makes sense (financially) to offer it on the higher priced vehicle (despite it (i.e. the vehicle) actually having a lower cost...) and thus I'm much more in agreement with Technic (esp. the bold part).

[Technic]

BMW is abandoning the elaborate (and I would guess, costly) multi-arm, strut-supported, trunk hinges for (cheap) curved, single-arm, spring-loaded hinges in most of its sedans/coupes.

These spring-loaded hinges open by just unlocking the trunk.

Originally Posted by sameh

Aside from aerodynamic design and weight saving, I read that the trunk lid actually opens when you push the button on key fob which I attributed to lighter weight. So does this mean F80 trunk lid will just unlock but stays down like on E92?
I know it's a trivial issue but my 9 years old daughter really struggles with the current weight of my E92 trunk lid.

[Technic]

My problem with the F32/F82 is not the greenhouse (perpendicular side-view). I think that it is fantastic.

But BMW put that greenhose on top of Honda Accord Coupe-shoulders, especially right below the kink. Too round, too mundane. The Sedan does not suffer of that misstep, it is classic BMW Sedan-shoulders.

I was expecting 6-Series shoulders in the 4-Series. They look like Dwayne "The Rock" Johnson shoulders/trapezius. If you put a 6-Series rear-view against a 4-Series rear-view you will know what I'm talking about. Even the 5-Series looks better to me from the rear than this 4-Series.

It was a missed opportunity to make the 4-Series look really outstanding in the segment, much more separated from the 3-Series.

Originally Posted by GregW / Oregon

I know this is all personal opinion, but I don't know how anyone could say the greenhouse on the sedan is better than the coupe's (see link).

http://f80.bimmerpost.com/forums/sho...2&postcount=72

[ss134]

Originally Posted by GregW / Oregon

Fair enough. Too bad the sedan can't be done with frameless door glass like the coupe, though, because that is much better IMO than the heavy sedan exposed B pillar.

Too bad the coupe can't have the aggressive taut stance of the sedan, the shorter rear overhang instead of a long elongated out of proportion rear........,,.. and no bulging wheel arches for the M4 either

Would have been nice to have frameless doors though...

[mkoesel]

Aftermarket might be able to step up to the plate in this area.

Personally, if I have a CF deck-lid I'd be inclined to at least consider having it finished to match the CF roof (clear coat), assuming the weave matches up ok. Might want the vertical surface on back in body color though.

[M4TW]

Originally Posted by sameh

Aside from aerodynamic design and weight saving, I read that the trunk lid actually opens when you push the button on key fob which I attributed to lighter weight. So does this mean F80 trunk lid will just unlock but stays down like on E92?
I know it's a trivial issue but my 9 years old daughter really struggles with the current weight of my E92 trunk lid.

Hopefully your daughter will also find the trunk in the F80 to be more spacious and comfortable than your E92's - though you might consider actually allowing her to ride in the back seat of the F80, since the sedan has four doors and would provide convenient access for her.

[SD ///M4]

Originally Posted by M4TW

Hopefully your daughter will also find the trunk in the F80 to be more spacious and comfortable than your E92's - though you might consider actually allowing her to ride in the back seat of the F80, since the sedan has four doors and would provide convenient access for her.

[roadmax]

Would like to have rear door delete on the M3, is it doable?

[Sedan_Clan]

Originally Posted by sameh

Aside from aerodynamic design and weight saving, I read that the trunk lid actually opens when you push the button on key fob which I attributed to lighter weight. So does this mean F80 trunk lid will just unlock but stays down like on E92?
I know it's a trivial issue but my 9 years old daughter really struggles with the current weight of my E92 trunk lid.

It's hinged on both sides just like an F3X, and it opens on its own when you pop the trunk (...too fast IMHO). My M-Performance trunk spoiler slowed it down, but not by much.

[mlai]

Originally Posted by roadmax

Would like to have rear door delete on the M3, is it doable?

Just weld it shut

[bavarian19]

Originally Posted by Tonymiabmw

Feel like CSL trunks looked crappy on e90

There is no subtlety to that trunk.

[bavarian19]

Originally Posted by GregW / Oregon

Fair enough. Too bad the sedan can't be done with frameless door glass like the coupe, though, because that is much better IMO than the heavy sedan exposed B pillar.

If it comes, M4 GC should address that issue.