E21 diet - go faster thoughts

[jrcook320]

So I was tinkering on my car last night, and I had a few thoughts on things I can do to optimize performance. I'm not sure how much it's worth at this point though... just day dreaming.

Basically, with as light as an e21 is, any weight you can drop really makes a big difference. 100 lbs is worth about 1.5 tenths in the quarter mile for me.

Things I'm thinking about are:

-removing sub box, replace with amped 6x9's in rear deck. I need less bass and more midrange anyway.

-remove heavy factory carpet padding and replace with lightweight padding

-carbon fiber hood, and trunk lid (yeah, I know... been discussed millions of times, just day dreaming here)

-lexan rear quarter windows

-removing my roll cage

Here's some date: I weighed my spare hood yesterday, it weighed in at exactly 44 lbs without hinges.

I weighed my car on the scales over lunch today, and it weighed in at exactly 2410 lbs with a 1/4 tank, no back seat, no spare, no ac, with a roll cage and sub box.

If I can get my weight down to around 2400 lbs with a driver and get 300 hp out of my m10 (shoot, I've got to be around 230-240 in this cold weather), my car should be good for bottom 12's if I could drive and hook it up.

The stuff I'm thinking about now is the cheap stuff: padding, sub removal, maybe taking the cage out. I bet I can save 100 lbs just from that.

[DrewDude320i]

if you remove your roll cage, i'd buy it from you. They Use Lexan windows in the M3 CSL!

Removing your bumpers would take some weight off...but that might be a "for the track only" mod. Maybe you could fab up some quick releases or something??

Finding 200 lbs with the stuff you've already done shouldn't be too terribly hard - but you might find your car floating more and more over to the "gutted track car" look rather than the nice (yet fast) daily driver that it is now. And with a glass pack as your only form of "muffler," the removal of all the noise deadening material might make your ears hurt.

[Layne]

Sub box!?!? If you have a radio at all you obviously aren't serious aboiut keeping the weight down.

[dustbunny007]

if u run lower than 12's though u gotta put it back in heh

[TheNeek]

I've contemplated Lexan rear windows as well. Very tempting, and cheap. Not sure if the rear windows are contoured or straight though.f

Think about going from a dual tank setup to a single as well. Cap off the pass through between the two tanks (extreme, but would work).

Removable passenger seat for the track.

Take the battery out for track days too. Just jump start it.

You can make your car light for track days with a little ingenuity.

[jrcook320]

if you remove your roll cage, i'd buy it from you. They Use Lexan windows in the M3 CSL!

Removing your bumpers would take some weight off...but that might be a "for the track only" mod. Maybe you could fab up some quick releases or something??

Finding 200 lbs with the stuff you've already done shouldn't be too terribly hard - but you might find your car floating more and more over to the "gutted track car" look rather than the nice (yet fast) daily driver that it is now. And with a glass pack as your only form of "muffler," the removal of all the noise deadening material might make your ears hurt.

If I remove it it's not for sale either way. sorry. Yeah, the goal is to keep the car as close to it's current state as possible. It is still my daily driver and I don't want it gutted. I want to drop weight by removing stuff I don't need. When I remove carpet padding it will be replaced by a light weight alternative. I cut just the rear foot well squares off and weighed them yesterday, together they are 4 lbs. I bet I'd save 25 lbs taking all the stock stuff out.

Sub box!?!? If you have a radio at all you obviously aren't serious aboiut keeping the weight down.

It is still a daily driver, not a race car. My goal is to drop weight without reducing current functionality very drastically. I'm not removing the stereo, it's a must for me.

Like the cage, for instance. I like it too much to take it out right now, even though it's probably costing me 10-15 lbs.

[Greenfield]

I removed all of that factory sludge coating, and sound insulation from under all of the carpets, and then put the factory carpet back. If noise is a concern, it doesn't seem any louder to me.

We removed the sunroof, the cassette, and part of the frame and hardware- then welded the panel back in. Seemed like a good idea at the time. It definetly dropped weight from the car, but I don't recommend it unless you're gonna use a a fresh " non-sunroof" panel.
my .21 cents worth...

[rocket859]

Currently the orange monster (my car) weights in at sub 2500 with me in it. All the padding, has been removed, i have rear seats, and i have a spare in my trunk, with tools, and a 20 LB Toolbox in the back.

I am going to be dropping another 200 LBS soon (dont ask how) and its all due to the 40 LB Passenger seat, and 50 LB Rear seats, carpet, and some stuff it can stand to loose anyways. But i will be putting it back with steel rear reinforcements, steel front reinforcements, and a roll cage made of 1.5" tube, mandrel bent.

[Layne]

50 lb rear seat!? What did you use lead for the stuffing? The stock one is 20 lbs tops, I had it out just the other day.

[blitzed310]

What about cutting the trunk floor out and replacing it with aluminum?

That rear seat weighs nowhere near 50 pounds, I'd say its about 25#

[rocket859]

Fresh high density foam

[Greenfield]

The rear seats from an e30 coupe will fit with a little trimming to the backside foam, just to clear the seat belt reels, and anchor hooks. Weighs less than the horse hair/springs combo, and no more "crunchy" sound when people sit on it.

[autox320]

Stripped you can get down to about 2000 lbs. Then it's drilling holes and taking out sections of metal.

Since a cage is useless and pointless in autocross, I ditched it and never looked back. Gave up on entering hillclimbs as my original goal.

Besides the normal lists of ltw batt, seats, carpet. Additional ideas.
•Gut interior; all outside door handles (leave inside door handles only) window glass, headliner, rear seat and belts etc. ; leave only partial dash and 2 front seats
•Cut rear shelf make ltw cross brace for rear towers and rear shelf area
•front strut brace
•Cut any excess steel from body; example spare tire holder, and rear bumper retainers
•Remove bumpers
•Remove sunroof; replace with sheet metal panel
•fiberglass fenders, trunk lid, hood
•Trim and roll front and rear fenders
•Remove all vehicle wiring; replace with simple painless wire pro street
•Remove heater core and components
•Lexan rear side windows (1/8”)
•Remove driverside fuel tank
•lightweight side exit exhaust

Stick with your street car lol

[rocket859]

Ah, i love stripped down racecars. They make a nice hum when going @ 6000 RPMs

[Jmabarone]

judging by the estimates from people in this thread, I'm beginning to see that it won't be as hard as it seems to get down to 2200 lbs.
Jake

[Amir@AvusAutosport]

Rear seat since you have a cage anywhere and it's extremely unsafe to have anyone back there. Since it's your daily you can make light weight wood panels and paint them to make them less ugly. Cut out the spare tire metal, Smaller leightweight wheels for drag set up, fiberglass everything, Light seats for the front could make a huge difference. I will be doing the sheet metal sunroof sealing also so that will take weight out and lower the center of gravity.

[jjgbmw323]

Fitzgerald at one time ran Lexan side windows, a full cage, and gutted rear seat.

Josh is you remove the rear seat and CF the sunroof you will defiantely save some weight. I can get trunks made in CF, its just the hoods on the e21 are too complex to do CF effectively.

[kdanielson]

I removed the heavy rubber mat under my carpet and the carpet would not fit correctly without it.... That rubber does weigh a ton though.

ken

[blitzed310]

No one read where he said he already has the rear seat out

[Cruz]

I <3 the E21 Legion .

[jrcook320]

FAIL for reading comrehension.






What I want is a way to remove the carpet padding, replace it with something light weight, and have the carpet still fit ok. I'll work on something this winter.

[TheNeek]

Call me crazy but why do you have seatbelts for a seat that doesn't exist? That's a lb or two right there.

[blitzed310]

Yeah, the belts with the bolts is 5 pounds right there, duh!

[TheNeek]

FAIL for common sense comprehension JOSH!!!!!

[Layne]

You might try that silvery foil stuff, I think its called dynamat or something like that. Its alot lighter than whats under there, and roughly the same thickness if I recall. A little expensive though.