Originally Posted by swamp2
I'd bet against 3200 lb, again strongly bet against it.
Cheap core materials like cardboard can provide stiffness improvements in large sheet like structures but would not be used for more complex mechanical/structural type shapes. Due to language difficulties (wheel mounts, axle stools ?) I am not positive, but many of the items you list do not seem like good candidates for replacement by CF, certainly not a CF/cardboard sandwich.
We keep hearing about the capabilities BMW gained when they purchased a large stake in SGL Group. However, they are touting much of the CF production from their new Moses Lake, WA facility to be slated for the i3 and i8 vehicles. They are also claiming that their new industrial (as opposed to aero******* grade CF will be about 50% the cost of traditional aerospace CF, thus about $10/lb, still over 10 times more expensive than steel.
For the sake of argument if they want to save 300 lb with CF that will take about 100 lbs of CF replacing 400 lb steel (super coarse "back of the envelope" estimate here). That will then cost just in materials at least $1000, not to mention higher tooling (fixed) and much higher labor costs (variable). I'd estimate the total cost (not price, cost) to save 300lb at about $1200. That must be increased further by their desired profit margin. It may not sound like a lot in a $60k car, but you would be amazed at what large automotive OEMs will do to save a few pennies on simple things like fasteners. $1200 is a HUGE expense.
Again there will be innovation, there will be weight savings, there will be increased use of composites, CF and lightweight metals. The car most likely will weigh less than the outgoing model. However, 3200 lb is just not going to happen.
So your saying that $1200 is too much for weight savings? What if they were saving about $10k per engine? (just throwing that out there).
If interested, you might want to look into how BMW is using the CF a bit more there is a lot out there on it. They are ramping up the launch of an entire brand based on CF so yes they are pushing that but the CF will be used across the board. But have said publicly many times that thanks to BMWi the BMW Group will have CF advantages- Board members have announced the next 7 using CF from the BMWi/SGL establishment as well as M saying it.
Costs are less than what you are estimating. They are not autoclaving and using a system that is not more labor intensive or energy intensive from a cost perspective. That is how they can do any of this at all. They built in Moses Lake for the cheap renewable energy (make the fiber usually high cost) then it is woven in Wackersdorf and molded at the foundry in Landshut. By not autoclaving they save a boat load of money.
Is the weave as nice as the weave on the visible components like the roof? No, but it is nearly as strong. Having seen this stuff in action it is impressive (see crappy iPhone image). The target of the i3 is 30k units per year (some mainstream media recently published 100k but that is BS I have the BMW info with 30k).
While they have optimized the cuts for the BMWi models there is still "scrap" and that scrap can be then recycled into smaller items rather than be thrown away or reprocessed. So they look at multiple platforms per cut and use every last ounce they can. Stuff that would have not been used now has a purpose and is relatively cheap- (they do this with leather as well). F80 will be considered in these cuts and moldings- if the i3 doesn't sell then BMW will have a boat load of CF they already invested in so no harm in using it at that point.
The CF aramid sandwich on the CRT is an example of what they can do and what they will do- they had bigger plans than just the CRT but the board shot it down.