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Discussion Starter #1
Small background: had a 09 STI, stock weight 3360 lbs, stock power 240 WHP/ 250 WTQ... After engine and lightweight mods I was weighing in at 3100 lbs (that's with 10 gallons of the 16 in the car), 300 WHP/ 340 WTQ. Let's just say that was a huge difference and felt like a monster... that was just the stock turbo and injectors. Basic bolts on; I'd like to believe the lightweight mods helped A LOT, on top of the power mods.
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Now to the M3...
I searched and didn't find too much on it; other than lightweight battery. That is a good place to start, but the rear is always easy to pull weight off of.

I'm all about improving the power to weight ratio; almost like "easy" power with out putting strain on the engine and less wear on the car, as a whole.

Who out there have some good ways to drop weight?

What I can think of (expensive and inexpensive):
- Lightweight battery -Mini battery is said to drop around 20-25 lbs
-I was looking at the Deka ETX30L, weighs in at 22 lbs and has a CCA of 400

-Carbon fiber roof
-I have a "slick top" no sunroof, so that already drops around 40 lbs (from what I've read). For me the CF roof would only drop another 13 lbs.

-Lighter wheels
-Not sure what is out there, but I can imagine we can drop at least 20 lbs total.

-Brake kits
-I'd personally just do floating rotors. My guess is around a 15-20 lb drop, with better stopping capabilites.

-Aftermarket shocks/springs or coilovers
-Not postive what shocks and springs would drop; on my previous car coilovers would drop around 20 lbs.

-Headers/Full exhaust
-Again, didn't find too much on this yet. I'd imagine with the right system, you can drop around 30 lbs, from the headers --> back.

-Lightweight front seats
-Depends on what you get; I'd imagine you can drop anywhere from 20-50 lbs.

-Rear seats?
-Not sure how common, or cost effective, CSL rear seats are; wanting to drop weight and keep the rear seats, that seems like the best alternative. I'd imagine just pulling them out, completely, would drop no less than 50 lbs.

-CSL air box/aftermarket intake
-Either one would probably drop around 10 lbs, maybe more. Expensive for weight, but good potential for the engine if you have the right power mods.

-Carbon Fiber door cards
-More of hardcore mod, as you lose your side airbags. But I'd imagine you could lose around 20 lbs and have a "killer" interior.


That's all I can think of, off the top of my head; I'm sure there is more out there. that all totals to around ~200 lbs. Give or take some, since most of these weights are guesses.

Anyone else have any input on this?
 

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I seem to remember reading that you can shave off 300lbs if you are anal about it. Most people who are anal about it just do a rear seat delete. You can also remove the A/C, radio, etc. Pretty much strip the car down to barebones. Why would you do this? Its an M3. You can get a better performing car for racing for a lot less money :clap:.
 

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http://forum.e46fanatics.com/forumdisplay.php?f=41

hang out here, run some boost and retain all the amenities, still go fast.

If not, you can go square setup lightweight 18s (APEX acr 8s are still quite popular), dont change the hood unless its "dual sided" carbon fiber as all single sided vorsteiner or not are heavier than the standard aluminum m3 hood.

drivetrain too , like light weight flywheel,(I just got the ACT setup with pro (12? i forgot) pound chromemoly flywheel)

the door inserts and stuff in cf will not be cheap..but yes unless its a track star car, I would retain the interior bits.
 

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Discussion Starter #4
I seem to remember reading that you can shave off 300lbs if you are anal about it. Most people who are anal about it just do a rear seat delete. You can also remove the A/C, radio, etc. Pretty much strip the car down to barebones. Why would you do this? Its an M3. You can get a better performing car for racing for a lot less money :clap:.
yeah, but it wont be an M3 ;)

Do it for fun, better power to weight and because I want too.

I think a 3k lb M3 (hopefully less...) Would be nice and nimble with the weight taken off in the right areas. THEN do power mods.... It will make a nice difference in the over feel and performance of the car.
 

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Discussion Starter #5
http://forum.e46fanatics.com/forumdisplay.php?f=41

hang out here, run some boost and retain all the amenities, still go fast.

If not, you can go square setup lightweight 18s (APEX acr 8s are still quite popular), dont change the hood unless its "dual sided" carbon fiber as all single sided vorsteiner or not are heavier than the standard aluminum m3 hood.

drivetrain too , like light weight flywheel,(I just got the ACT setup with pro (12? i forgot) pound chromemoly flywheel)

the door inserts and stuff in cf will not be cheap..but yes unless its a track star car, I would retain the interior bits.
Ah yes, the,flywheel; i forgot about that.

One day I'd like to stroke it out and pull the potential out of that. Im trying ti stay N/A. I have a lot of turbo experience, I want to do something different.

I don't plan on running a CF hood. Same thing applied to my other old STi (06), had a lot of aluminium parts.

I do want to run square, what is the widest the fronts can be? I've read 255, but I'm not sure.

Cf door panels would be cool, but definitely too much. I'm sure i can find that weight somewhere else.
 

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Battery can drop probably 30.

the two front seats can easily drop 60 combined and still retain comfort. 80 or more if you go with agressive buckets.

ast 5100 shocks will drop a lot of weight due to the fact that they are made of aluminium.

You could drop 20 lbs in the wheels.

With a lot of negative camber, you can run 275/35/19 ET25 on 19x10s squared, but I don't know about 18's.

One of the most effective ways to drop weight will be from loosing your interior. By keeping it all there you are lugging around A LOT of weight that doesn't have to be there.

**Now, forget what was all just said in this whole thread and buy yourself a 4.10 differential and call it a day :clap:
 

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Replacing the stock muffler with something else will save a ton of weight, it's about 56 lbs. An lightweight muffler should save you 20-30 lbs right there. Headers are probably good for another 10-15. As far as suggestions not mentioned yet: you could remove the sound deadening rubber under the rear seat as well, it definitely has some weight to it.
 

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I weigh in at 3,380 (wet) with relatively light wheels, after market muffler (that was 25 lbs!), no back seat, recaro fronts and a 4 point cage. I was 3490 (wet) with my previous set up (with a sub and amp)
 

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I weigh in at 3555 wet with driver.

Me: 160lbs
Full tank of gas: 125lbs
Subs, amp, rear seat, stuff: 150?

that's 435lbs that I could drop out, leaving my min weight at about 3120lbs.

I could loose my passanger recaro seat for 35 lbs, install my AP headers for maybe 10-15.

I've already got carbon fiber hood and trunk, cat-back exhaust, recaro seats, and light weight wheels.
 

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Discussion Starter #10
4.10... Where do I find that?!

Is like to run 275 up front... That would be awesome.

All good advice, keep it coming. I want to hear more about your "lightweight" M3s!

So, what is the actual curb weight of an M3 (wet)? I don't have a sunroof, has kardon whatever and power seats.
 

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4.10's aren't made any more, so you'll have to get them either custom or find some used.

I'd say an honest wet weight would be nearly 3400 lbs: full tank of gas and no driver.
 

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Ah man, not made anymore... Booooooooo!!!! Does it make that much of a difference?

Not too bad, thats what I read, just wasn't sure how accurate it was.
 

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Ah man, not made anymore... Booooooooo!!!! Does it make that much of a difference?

Not too bad, thats what I read, just wasn't sure how accurate it was.
 

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4.10's aren't made any more, so you'll have to get them either custom or find some used.

I'd say an honest wet weight would be nearly 3400 lbs: full tank of gas and no driver.
Kind of a false statement. BMW Motorsport 4.10 ring and pinion are not made anymore but there are still places like Turner and BimmerWorld that have some in stock. There are also still a number of other companies that make a 4.10 ring and pinion for the e46 M3, I just ordered a set yesterday. Diffs Online being the most popular.

As far as weight goes you're not gonna be able to get below 3k lbs without removing everything and I mean everything. Carpet, sound deadening, audio, ect.

One thing you didn't mention was a CF trunk. I think OEM weighs 40+, you can get a good CF that weighs around 10. Like others have mentioned, exhaust is a good place to loose weight although its not the best place on the car since its at the lowest point.

Here are a few pics of my car:




This car with nothing left to remove but the AC. It has race seats, and no sunroof, it weighed in at 2,928lbs just the other day. Fully wet with a 1/2 tank of gas. I do have a heavy ass 70 lbs roll bar though.
 
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