[longodj]

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)

SUGGESTIONS:
-Headers
-LTW Control Arms
-Interior Panelling
-FMIC
-Downpipes
-Intake

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.

Thanks,
Dave

UPDATE May 31, 2008: My car weighs in at 3740 with Kosei K1/Bridgestone RE01R

[JoeT]

don't take this the wrong way but why not pick up a dedicated racer rather than rip up a perfectly nice and capable car? if you wanted to gut the vehicle (mind you, I own such a beast usually on jackstands in the garage) why not pick something for racing in a specific class...

such as a spec miata, or something along those lines.
good luck with your gutting, I guess

great cars to gut for racing:

EVO RS's, C5's, miatas, F-bodies... etc

not so great cars to gut for racing:
brand new E90/E92's

[MrFrizzle]

Yeah man, our E90's aren't meant to be light cars. Your suggestions to reduce weight are good, but to effort+cost vs. benefit might not be enough. You can drop 150lb on a 3800lb, but what is that really going to do for you? More than likely, you aren't going to notice much of a difference, especially when you are racing 3000lb cars.

Another weight trimming suggestion...
You can go on a diet

[toofasttooslow]

Just curious were there any 335i's or M3's participating?

[uberschnell]

How about paying a jockey to drive for you, should be worth 50 to 70 pounds

- seriously though, a lot of the mods you mention come with a downside so why do that to a luxury car?

[longodj]

hah, yea I know what you guys are saying and agree. My roommate has actually convinced me to pick up a 240sx next year for actual track use...like I want to get a NASA license type of track use. I mean with those cars you can get them down to 2000lbs or less pretty easily in a dedicated racer set up. But just for autocross and HPDE I'd like to have fun in my car, and the reason I like the mods I mention is they are "permanent" and have few downsides. I don't know...why not I guess? I mean I want to wring the most performance out of my car and I'd rather not start with the engine because it's pretty hefty already. I've been looking at sways (in-development), I'm saving up for wheels/tires and coilovers. But past that, the only real mod non-engine wise that really really benefits handling and such is weight...soo.....why not?

I guess I want to turn our performance luxury automobile into a luxury bat out of hell

[longodj]

Originally Posted by gum5h03

Just curious were there any 335i's or M3's participating?

There were a bunch of different M3s participating, daily driven and race dedicated, and z4s and they came close but the STI still came out on top. I was really just using that as an example of the close competition anyway. The only 335 was me

[MrFrizzle]

oh and one more thing...

It will be a sad sight to see racing seats in a 335i.
Sad.

[longodj]

Originally Posted by MrFrizzle

oh and one more thing...

It will be a sad sight to see racing seats in a 335i.
Sad.

lol, why do you say that? I mean, Recaro Pole Positions aren't THAT different from the sport seats, especially after being reupholstered to match....they'll just be missing the many MANY pounds of actuators and such.

[S4to335]

Well, I think I got mine down to 3400 with changing out wheels/tires/exhaust/brakes/suspension. Seats are NOT 100 lbs each..trust me. I use to campaign an Audi S4 in autocross in 2000...I got 3rd place in C-Street Prepared that year in SF Region..went to 17 autocrosses..I think...mine had SSR comp wheels/r compounds/catback exhaust/suspension/aluminum control arms.

[berreli]

I think the biggest culprits for weight on your car are two things you cant do without.. AWD and two Turbo's.

Bimmers are heavy, right in the sheet metal. I'll agree with the above comments about picking up a dedicated racer and keeping your car a pimpin street machine.

But if you do go ahead and do it... I'll be perfectly willing to make you an offer on your sports seats as part of my ZSP retrofit project.

[longodj]

lol thanks yea....damnit fat car....alright well I guess the plan is to go ahead with the hood, boot, wheels, and battery and stop there. I'll pick up a 240, drop a big ka24de in it and strip weight and make that my real racer if anyone does have any other ideas though, please do continue posting :-D

[HRC]

Go for the 240 and keep the CF and racing-sheel seats off the 335! IMO, the effort put into the 335 will not yield the preformace benefits you are seeking compared to getting a track car and you will take some class away from your daily ride. But hey, if you like the racer look for your 335 then go for it.

Danny

[shimshimhada]

Originally Posted by longodj

lol, why do you say that? I mean, Recaro Pole Positions aren't THAT different from the sport seats, especially after being reupholstered to match....they'll just be missing the many MANY pounds of actuators and such.

Don't listen to him. Buckets rock.

As for losing weight...I don't know what your gf's tolerance level is, but this is what I did in my E46:






That combined with some 17" Koseis and suspension yielded a weight loss of 300lbs. The rear seat cover (back piece and bottom) take 2 mins to remove and put back, so you can leave them in during normal driving.

After doing that you could probably get down another 100lbs if you change out the passenger seat, change the exhaust system, and get a ltw battery.

After 400lbs, you'll probably start to affect daily drivability.

[Getagrip]

OP- When you start drop that much weight (even just the CF hood) it will put you into a different class with even more competative cars. Something to think about. Just leave the car stock and get some R-compound tireans just have fun or get another race specific car. Not flaming here, as I have run E46/E90 Xi BMW with overall PAX championship wins the past few years.

[S4to335]

Yeah...Street Modified is not fun unless you are truly really modified like Vic Sias.

[just4kickz]

Originally Posted by shimshimhada

Don't listen to him. Buckets rock.

As for losing weight...I don't know what your gf's tolerance level is, but this is what I did in my E46:






That combined with some 17" Koseis and suspension yielded a weight loss of 300lbs. The rear seat cover (back piece and bottom) take 2 mins to remove and put back, so you can leave them in during normal driving.

After doing that you could probably get down another 100lbs if you change out the passenger seat, change the exhaust system, and get a ltw battery.

After 400lbs, you'll probably start to affect daily drivability.

haha thast what my friend did to his suby. totally gutted it.

[shimshimhada]

Originally Posted by S4to335

Yeah...Street Modified is not fun unless you are truly really modified like Vic Sias.

Anybody looking for a ginormous rear spoiler?

[sflgator]

Obviously weight reduction is a huge factor, but if you're already planning on a better (track worthy) suspension setup (sway bars, coilovers, super light weight wheels/tires, etc.), then why not just add a piggyback like the PROcede v2 with your new suspension, and you''ll be the one demolishing most of the cars out there. I believe this has already been done by a few members of E90Post.com, like leftcoastman, I believe...do a search.

EDIT -- saved you some time; here's his thread...

http://www.e90post.com/forums/showth...t=leftcoastman

[Don Nguyen]

Let me know if you need help getting those lighter parts for your car, as I can provide you with basically everything on your list

What you didn't mention, but other posters already mentioned it, is getting lighter wheels.

Look into the D-force LTW5 wheels that we sell. Very cheap, comes in an assortment of sizes, and VERY light.

Let me know if you have any questions or need help with anything.

thanks.

-Don

[hotrod2448]

You will be wasting your time trying to get that much weight out of the car and have it be a civil daily driver. I get what you want to do but, it is just kind of pointless when cars like STI's and Evo's can do the same weight reduction mods and be even lighter.

Just go buy a shifter kart. You can get a used one for less than you would spend on mods to competitive in autocross (wheels, tires, exhaust, coilovers, swaybars, weight reduction, etc..).

[ironic]

there are some things u can do easily. for me, i'm going to be getting a cf hood (already have the cf trunk). you can also remove the rear fold down seats if you don't use them. a light weight battery is another good option.

i mean a lot of the guys on here make a good point about not being nearly as effective as getting another dedicated car, but if you want to race in your daily so be it. i mean, think about all the guys that race on a 1/4 tank or without a passenger.