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      09-13-2008, 12:09 PM   #50
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Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

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Originally Posted by longodj View Post
Hey Guys,
So, at the last autocross I went to, a WRX STI demolished every BMW in its tracks. The STI is 3300 lbs. My brother has been eyeballing a Porsche Cayman S and will probably be getting one before next autocross season, and I'm trying to get him into autocross. The Cayman S is 3000 lbs. My roommate drives a Nissan 240sx. 2800lbs

Now, I drive a 6MT 335xi E90. 3800lbs. My brother has pretty much always beat me at everything (except anything technical but that's a whole nother story for a whole nother day), so I'm looking to drop some weight from my car.

Hopefully this thread will stand as a central place to find where to drop weight from our cars. I'm looking to drop at least 200 lbs while still "feeling" stock and being daily drivable....i.e. while keeping my girlfriend from killing me every time she gets in my car Maybe in a year or so I'll jump for nice racing seats reupholstered to match my Terra but that's a bit too deep for my pockets atm. So by daily drivable I mean keep all audio/nav components, A/C, etc.

I fully understand that this is sort of ridiculous so please do not flame me, if you don't have anything helpful to say relating to this issue please do not post. I also fully understand that our cars aren't necessarily designed to be light and aren't the greatest to start with if looking for light. I ALSO understand that weight isn't everything, but hell WHY NOT drop a few pounds right? I'm already on a diet

Here's what I have found so far, although I don't know of most of the exact weight savings numbers... I don't know if I will personally be able to get well....any of these before next season but if I can get an idea I might be able to scrap some together :-P

-Wheels/Non-RFT Tires (Unsprung): ~45lbs
-Lightweight Battery (Rear): ~40 lbs (stat by HP Autowerks)
-CF Hood (Front): ~30lbs
-CF Boot (Rear): ~15lbs
-Exhaust (Center): ~20lbs
-Removing rear seats (Rear): ?? (for track days...)
-Replacing front seats (Front): ~80lbs (stat by HP Autowerks)

-LTW Control Arms
-Interior Panelling

Anyone know of any other permanentish mods that dump weight without damaging daily drivability? Preferably the mods would be in the front to dampen that 53/47 or so split we have going.


UPDATE May 31, 2008: My car weighs in at 3740 with Kosei K1/Bridgestone RE01R
I was curious about the exact same issue with my E9X M3, and started a similiar thread on the other forum some time ago. I was able to remove about 25lb of stuff from the stock setup that does does not affect driveability. Based on my research, I calculated that the next 100lbs will cost something in the order of $15k when you consider weight reduction only (you obviously get other benefits such as slight hp gains and rotational intertia reduction and so on from exhaust and wheel mods). Anyway, I documented what I found here (some of those mods might be relevant to the 335):

Also, my E92 M3 came in 3497.5 lb on a scale at NHMS with half tank of gas, and no driver, which means it would come in at ~3550 lb with a full tank. (L: 1725.0 lbs
R: 1772.5 lbs) This is consistent with what magazines have been reporting.