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      07-18-2013, 02:13 PM   #91
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Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Originally Posted by solstice View Post
1. BMW can decide if it's 100 lbs or 150 lbs. It's 100 lbs on the scale for the base M3 car vs the CRT car. The 150 lbs is when you consider the weight from the extras in the base CRT as for example DCT etc.

2. Well either BMW is lying or the seats are heavier than your source state. It's one of the two.

I've seen info about the front seats being +60 lbs and the rear ~45 lbs. that's a 165 lbs combined. Shaving 50 lbs from that seems more than doable with CF and BMW show what they can do by saving more than twice of that.
The rear seats are indeed about 45 lb. As some useful reference material here is a great thread on how much it costs with aftermarket parts to save a given amount of weight in the E92 M3 (link).

So yes, indeed one has about 170 lb (again based on link above) to work with for seating weight in the E92 M3. That also assumes the 435i seats haven't already undergone some lightening work which surely they have. You can reduce the weight on many fronts, leather, foam, electronics and most importantly the motors and steel frame parts. There is very little steel in the rear seats and no motors. Thus the vast majority of the savings will come only from the front seats. The challenges are that M3 owners expect a daily driver. You can't put non power seats in, some may call that sad, but it is the reality. You also can't make really firm minimal padding seats. BMW also won't sacrifice on safety. Thus if a seat airbag got nixed it would probably migrate to a door. Last but not least carbon fiber is extremely expensive. So thus again, 50 lbs is roughly 50% of the front seats and that is extremely aggressive and doubtful.

Look again at the link above using BMWs own seats already available:
  • BMW performance bucket seats with side airbag: 55.7 lbs
  • Weight savings 14 lb (both front seats)
  • Cost $5000 (back in 2008 from Turner Motorsports)

IT COSTS A LOT OF MONEY TO SAVE WEIGHT! Sure that is not BMWs cost but fancy light seats with safety are darn expensive and not consistent with BMWs agressive cost savings programs.

Anyway back to the M4. A modest perhaps 30 pound savings is certainly possible. However, BMW may provide and optional seat, likely IMHO, such seats could be more extreme in design, not have motors and save way more than 30 pounds. But again they will be expensive and optional.

I'm not being a pessimist here, just an informed realist.
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |