Weight reduction ??

[bimmerfrk]

Fill tires with helium. Good for another 150lbs

[W///]

Buy a Miata

[1MOREMOD]

Strip all interior, race seats, take out hvac and all wiring, bbk, light weight wheels, exhaust, go from there.

[Amirsm3]

Originally Posted by bimmerfrk

Fill tires with helium. Good for another 150lbs

[italyix]

This is the route I am currently taking to reduce weight on the E90 porker.

Challenge CF Roof shaves off around ~50lb (I have moonroof)
Voltphreaks VPH-900 shaves off another ~50lb (stock is 60lb and this one is less than 10lb)
Volks TE37SL in 18" flavor shave another 6lb off each wheel (my stock 18" weight something like 24lb? and the Volks are ~18lb)
Michelin PSS weigh a few lb less than the Michelins that came with the car (the previous generation to the PSS)

Thats at least ~100lb of dead weight plus the rotational and sprung weight being removed should help with weight. Eventually (when my stocks go up a bit more), seats will get swapped out to Recaro Sportsters CS which weight half of the stock seats (so 60lb for both seats out of the car). CF hood and truck is good for another ~40lbs or so, which would bring me to ~200lbs of the car. If I can be in the high 3.5k lbs I'd be happy.

[GTB/ZR-1]

Originally Posted by italyix

This is the route I am currently taking to reduce weight on the E90 porker.

Challenge CF Roof shaves off around ~50lb (I have moonroof)
Voltphreaks VPH-900 shaves off another ~50lb (stock is 60lb and this one is less than 10lb)
Volks TE37SL in 18" flavor shave another 6lb off each wheel (my stock 18" weight something like 24lb? and the Volks are ~18lb)
Michelin PSS weigh a few lb less than the Michelins that came with the car (the previous generation to the PSS)

Thats at least ~100lb of dead weight plus the rotational and sprung weight being removed should help with weight. Eventually (when my stocks go up a bit more), seats will get swapped out to Recaro Sportsters CS which weight half of the stock seats (so 60lb for both seats out of the car). CF hood and truck is good for another ~40lbs or so, which would bring me to ~200lbs of the car. If I can be in the high 3.5k lbs I'd be happy.

Good plan!

How much is that roof?!

[italyix]

Originally Posted by GTB/ZR-1

Good plan!

How much is that roof?!

$1270 plus $140 shipping, directly from Challenge. Takes 2-3 weeks to make and I'm dropping the car off at the shop on 8/19

[GTB/ZR-1]

Originally Posted by italyix

$1270 plus $140 shipping, directly from Challenge. Takes 2-3 weeks to make and I'm dropping the car off at the shop on 8/19

WOW--not too bad for that much weight, up that high...

How reversible is it, though?

[lve2xlr8]

Anyone know if the fancy lightweight f8x battery will swap into the e9x?

[ilikebmxbikes]

I cut 400lbs off my m3

[Richbot]

It's not hard to drop weight from the car, just expensive if you want to do it without making the car worse.

[schnell325]

Recaro PPs and rear seat removal nets around 120lbs if I recall...

[TurboBimmer]

Originally Posted by okusa

Surprised nobody mentioned sunroof delete (if applicable) and replacing glass with Lexan which is about 2.5X lighter.

I replaced my sunroof with an oem M3 cf roof. Worth 45 lbs in weight savings.

[radiantm3]

Originally Posted by Petros

Nope. No easy way. E9x M3 no matter what you do will remain a heavy car. Replacing the battery, seats, exhaust, brakes, wheels may net you 100 lb or so. Gutting the interior might offer a few dozen more, but that's it. Look at the GTS. It's totally stripped out yet isn't all that light either

My car is about 3300lbs dry. It was a fully loaded car new. Full titanium exhaust alone nets almost 40-50 lbs alone. Stock seats are like 80lbs each.

[roastbeef]

Originally Posted by lsmkr01

You noticed a 35lb difference on a 3600+ lb car???? Thats less than a 0.01% change buddy, placebo affect perhaps.

it could very well be the placebo affect. the car does feel like it shifts harder with the lighter exhaust though.

[italyix]

Originally Posted by GTB/ZR-1

WOW--not too bad for that much weight, up that high...

How reversible is it, though?

Irreversible. Stock roof tack welds get cut out and cf roof is glued in.

Ilikebmxbikes has the cf roof as well, replaced the stock one with moonroof. Marco, what was ur weight savings with it? Did Ptech weight it?

[Richbot]

Possible to make a non-sunroof car about 80-100lb lighter without making it significantly worse or less safe as a street car. Beyond that you start getting into fixed back seats without airbags and stripping out other features of the car.

25lb in wheels, 15-20lb in brakes, 20-45lb for a reasonably quiet exhaust, carbon roof on a non-sunroof sedan is worth about 10lb, then there's some 30lb of savings in the BMW performance seats that retain the safety features of the stock seats, obviously diminishing returns at that point. Battery is an open question the Voltphreaks battery is promising but I would be concerned about fire and long term impact to the cars charging system. Z4M battery is still 75Ah I believe and worth 15lb

[GTB/ZR-1]

How durable are the factory CF roofs to sun exposure? I didn't realize the coupes & sedans shared the same roof demensions.
Also, I wonder it doing that would kill resale? I don't use the sunroof anyways, so it would be a positive to me as a performance-oriented buyer.
Also, would a mint stock roof & sunroof assembly would have some value, to offset some of the conversion cost.

Thinking out loud here... lol

[Rggity]

Originally Posted by lsmkr01

You noticed a 35lb difference on a 3600+ lb car???? Thats less than a 0.01% change buddy, placebo affect perhaps.

It's actually almost a 1% change.

[lsmkr01]

Originally Posted by Rggity

It's actually almost a 1% change.

Correct. Not sure where my head was when i posted that

[m3ray]

Originally Posted by bsacamano

Each time you get in the car, fill the cabin and trunk with helium.

[Richbot]

Originally Posted by GTB/ZR-1

How durable are the factory CF roofs to sun exposure? I didn't realize the coupes & sedans shared the same roof demensions.
Also, I wonder it doing that would kill resale? I don't use the sunroof anyways, so it would be a positive to me as a performance-oriented buyer.
Also, would a mint stock roof & sunroof assembly would have some value, to offset some of the conversion cost.

Thinking out loud here... lol

The coupe and sedans don't share the same roof dimensions the Challenge part is a custom part

Personally I would have it painted body color if I did it. Raw CF is just another unpainted body panel as far as I'm concerned. I realize I'm in minority here.