Stripped weight: How much can I pull from a 535i?

[Gil554]

Having done some poking around here, roadfly, and others I am attempting to figure out what sort of weight can I pull out off a e34 535i? I aplogize if this is a repeat for you having read my post on roadfly but here it goes!

I have owned and maintained several e28's (m20 and m30) and a e24. I love the lines of the e34 and enjoyed the m30b34 immensely and I am sure I would appreciate the b35 even more.

I am just trying to get rough numbers from the interior, accessories, and comforts...I am aware this is a gt car and not a club racer but at the prices these cars can be had for I am thinking of lining a 535i up for next winter's project car. This would not be a DD.

Here are a few things that I would toss out for a stripped out 2 seater sleeper. I am looking for input on #'s you may know or I have left out.

-jack, spare, kit ~60lbs

-insulation, carpet from cabin and trunk ~25lbs

-rear seat ~25lbs

-door skins, trim, headliner ~40lbs

-swap seats for manual cloth non-adjustable ~100lbs

-dash and associated plastic ~25lbs

-radio, hvac ~25lbs

-ac ~65

-window motors ~10lbs

-lightened wheels and lower series tires ~25lbs

-aluminum control arms (any car I buy will undoubtedly have a shimmy) ~5lbs

This results in around 400lbs pulled out! Where can I take more out? Where am I wrong on weight?...other more expensive options include replacing the exhaust manifold and exhaust, suspension components, lexan, fiberglass/cf (yeah right...), and of course power adders.



This is sort of a fun exercise and I appreciate your input on weight!


Gil

[Paul in NZ]

sounsd insulatin from floor hood and elsewhere,and you could run a much smaller battery

[Gil554]

sounsd insulatin from floor hood and elsewhere,and you could run a much smaller battery

Two good points!

Looks like the Odyssey PC925 battery will save about 20lbs over the OEM unit and I'll add another ~10lbs for insulation removal (does this sound like a fair amount?)

Giving a running theoretical total of 435lbs! :D

Any other thoughts?

[Ross]

In addition to the window motors the regulators can be removed also, a strap connected to the bottom rail can be used raise and lower the glass(plexi?). There are five lock actuators no longer needed, the handbrake, heater core,valve, and hoses, sunroof motor and hardware, center console. you will have lots of unused wiring also.

[Tiger]

Talk about bare boner! No windshield washer fluid would help too or as little as possible. Suspension components... as much aluminum as possible...

Seems like everything else would start costing money... fiberglass hood, trunk if possible? lightweight multi pieces wheels, coil over setup... aluminum brake calipers, definitely exhaust system...

[Gil554]

Excellent suggestions Ross and Tiger!

-I think I would stay away from lexan for the front passenger and drivers windows but it might be worth looking at replacing the rear windows with plastic. Lexan isn't street legal here in Washington due to safety concerns during a crash.

-Sunroof and motor removal ~30lbs

-Lock actuators and associated wires ~10lbs

-Heater core ~15lbs

-Center console ~10lbs

-Random wires and hoses ~15lbs

~Windshield washing fluid, container and hoses ~10lbs (may want to keep this one)

I have seen one CF hood for the e34. Does anyone know a source of fiberglass panels? I am guessing not, but ya never know!


Running total: 515lbs of theoretical removal

Thanks for the input!

Anyone who has replaced the exhaust or suspension components care to chime in on weight differences?

[repenttokyo]

if it's a race car, and you don't have to run an exhaust at all, then pull all the piping and run open headers. Or at the very least, run a short pipe out the side. That will save you a lot of weight.

[bahnstormer]

plexi glass windows
and swiss cheese the metal for another ~100 lbs

[Tiger]

Don't remove the steel beams on the doors... that keep you alive.

[Gil554]

Thanks for the input!

This would be street legal and have to get smogged so no straight pipes :(. It would be used as a track day fun car, autox 10x a year, and startling passengers in-between. Although if I replaced the exhaust system it would be without resonators and a single high flow cat and high flow muffler. Which by the looks of it could save 20lbs or so.

-Replace exhaust ~20lbs

-Pull plastic from wheel wells ~15lbs

-Possibly use lexan rear windows ~20lbs

Question: Does the e34 have steel beams in the doors? As I would pull the back seats I would also pull added steel support in rear doors.



Running theoretical total: 550 lbs removed :D

This would put the car right around 3000lbs!

Thus far the only cost would be the exhaust.

[repenttokyo]

I think your wheelwell plastic estimate is high by about 8 lbs.

[Gil554]

Don't remove the steel beams on the doors... that keep you alive.


Agreed on that. Just a thought for the rear doors which wont have seats or passengers.

[Gil554]

Dang! Lets take it down ~10lbs for good measure

Running total: 540 lbs theoretical removal!

[Coldaccord]

why the heck do you want to strip an e34.

its a fat pig.

i like mine because its a nice comfy daily driver

if you want a track car buy an e30. strip an e34 all you want it will still handle poorly in comparison

[Gil554]

why the heck do you want to strip an e34.

its a fat pig.

i like mine because its a nice comfy daily driver

if you want a track car buy an e30. strip an e34 all you want it will still handle poorly in comparison


Not to be snippy but I was asking around as a fun exercise about theoretical weight removal. At approx 3000lbs stripped with an aggressive suspension, camber control, and r-comp tires there are a fair number of DSP e30's that would be surprised. Even still I understand a stripped e34 wont have the same balance that it left with from the factory.

If I follow through it a build-up like this it would be purely for fun and unique experience. My current DD weighs in at 2400lbs but would still be left behind by a 3700lb e92 M3.

[Paul in NZ]

....aux water pump,ABS,alarm(i assume it wont actually be driven on the street )except to close events....did someone already say air con....

[Ross]

This is an interesting exercise. I would be curious to know lap times before and after the weight shedding to quantify the change.
The E34 might be fat at 3400# but not at 2900#. The car will accellerate, brake and corner better. The best bang for the buck there is.
An extreme example was demonstrated years back by Hot Rod(?) magazine. Loading a Cadillac sedan with hundreds of pounds of extra weight then removing it bit by bit until little more than a bare chassis remained. The tired old smogger Caddy ended up running mid 12 second traction limited 1/4 miles as I recall. Braking and cornering weren't tested but would certainly have improved also.

[Tiger]

Yes, but it is integral for the whole side of the car... take a link off the middle and the structure is compromised real bad.

[Gil554]

This is an interesting exercise. I would be curious to know lap times before and after the weight shedding to quantify the change.
The E34 might be fat at 3400# but not at 2900#. The car will accellerate, brake and corner better. The best bang for the buck there is.

Thanks! I find thinking up projects almost as much fun as wrenching...almost!


Here is a fun 0-60 calulator (generally acurate within a few 1/10ths):

http://www.060calculator.com/


Seeing the wieght reduction from 3570 to 3100 lbs (3570# taken from wiki) will knock 7/10ths off from 0-60. Following the bmwe34.net (which is a very nice site as a side note) "Power recipe" 0-60 times may get into the mid to upper 5's. I am not saying this will make a dragster, but it may suprise more than a few! :p

Thanks again to all of you for your input and I do apreciate your insight!

[Gil554]

Yes, but it is integral for the whole side of the car... take a link off the middle and the structure is compromised real bad.

Fair enough. I wont take structural modifactions into account in terms of weight loss.