Lets talk weight reduction

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Lets talk weight reduction

Postby Fasterthansome » Wed Oct 30, 2013 7:42 pm

Has anyone cut the floor and firewall out of a Monza and weighed the parts? Also what is the lightest fully gutted full floor and firewall Monza anyone has seen? Im at a crossroads and want to go light. Do I cut the floor out and chassis the car while still retainging stock suspension locations or gut every ounce I can out of the car and keep factory floor/firewall. Was going to do a S+W 25.4 mild steel chassis tied into factory front suspension but by the time I add all the tubes how much weight reduction. Considered a square tube frame and 12 point cage with a full skin job for ease of build but then theres the 8.50 cert issue.
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Re: Lets talk weight reduction

Postby megavega » Fri Nov 01, 2013 1:46 pm

Thats right, by the time you cut out the floor and frame, the mild steel you add back in with the bracing and such will be heavier then the thin sheetmetal you remove. The floorpan is not all that heavy. The front inner wells have a bit of weight to those so you can eliminate those and run support tubes to frame horns and tie into rollcage.

I think youll find the glass in the car,windshield, rear windows, side windows to be heavierr then alot of the steel is, as these cars are made of layers of thin sheet metal.

what about the bumper supports? have you stripped those out and just used aluminum tubing to hang them?
Doors can have the windows removed, crash bars removed and then treated to a holeswaw on the undersides, they get fairly light then. fiberglass fenders,doors and such will remove weight but usually they dont fit very nice.
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Re: Lets talk weight reduction

Postby Fasterthansome » Fri Nov 01, 2013 5:46 pm

Doors are missing regulators and inner sheetmetal one has crash bar still in it and lexan. Front bumper gone with alimunum tube replacing it complete rear bumper still in it.. Car has exhaust to axle dual batteries so going to one battery and headers out the fenders I think.
Also cut every ounce out of front I can and tie in with a tube. Also going to cut forward of a arms and do some round tube forward and small tube for radiator etc. Eliminate the old power steering box and all steering linkage and do a rack. Thinking about cutting out the mild steel 8.50 cage and going moly 8.50 with rocker bars and x door bars. Old cage is 1- 3/4 roll bar then added rest of cage later so a bit heavy. I am thinking I can do Lexan in the hatch and possibly skin or lighten the inner part of hatch, might be worth a few lbs. Not sure about windsheild yet but on a mission to get light. I was also considering removing some of the fender and 1/4 under the Mirage panels maybe a few more lbs there.
Would be nice to know how light one could get too.
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Re: Lets talk weight reduction

Postby megavega » Fri Nov 01, 2013 10:31 pm

whats your weight now?

I have done quite a few vegas into chassis cars and you can get around 2200-2300lbs with sbc and still pretty much have a car with the mods previously listed, when they get under 2000lbs they are just a mere shell, pretty flimsy. I am sure your just after the weight reduction so that may or may not be a issue.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
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Re: Lets talk weight reduction

Postby Fasterthansome » Sat Nov 02, 2013 8:48 am

Currently right around 2900 without me in the car. I would like to be closer to 2400. :th: Been looking at monza nose and rear bumper in fiberglass but unsure about how much weight savings eill be over the factory urethane parts. looks like 600$ plus shipping to go that route plus repiant parts so unsure if the weight loss warrants the price. Cant find a weight on factory parts.
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Re: Lets talk weight reduction

Postby megavega » Sat Nov 02, 2013 10:46 am

ok, so, 500lb reduction is the goal. I would say cutting out the front inner wells and also the reduction of the headlights,front bumper/core support,going fiberglass front nose part is likely worth a 75-90lbs or close to it, the front inner wells are pretty beefy. I know the pile I have when removing all that upfront is fairly drastic .
The differance in cage from 1 3/4" mild steel to 1 5/8" moly will be quite a bit also. The windshield and rear hatch glass is likely 60+lbs alone. Getting rid of 1 extra battery is 40lbs. Steering column/stock sector shaft is 20lb, you can go to a moly tube column from jegs,etc. go to a vega manual box will save about 5-6lb over the bigger monza pwr steering box.

Actually since I am talking about it, a conversion to a rack will save every bit of 75+lb, the stock steering box,drag link and tie rods.etc is alot heaveir then people think. Get a rack crossmember from Justin in moly.

I would just take off all your interior panels and send the holesaw zippin in every panel then just put the plastic panel back on, the plastic panels dont weigh anything and keep the car looking like a car and not a strainer.....lol

I think your goal is more then doable, just have to focus in the right areas.

firewall is thin in these cars and no real weight savings there to remove it and tin it, its only a single layer thin sheet anyways.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

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Re: Lets talk weight reduction

Postby megavega » Sat Nov 02, 2013 11:06 am

some pics of gutted front ends, removed wheel wells and core supports,etc.
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1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

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Re: Lets talk weight reduction

Postby stage169 » Sat Nov 02, 2013 11:44 am

Didn't know if you have seen the Jegster front end before? http://www.jegs.com/p/Jegster/Jegster-V ... 3/10002/-1

Chop approximately 200 pounds off so they say.

I liked how Bill tied his bars to the stock suspension. Keep us posted on what you finally end up doing I'd like to see the build :th:

Brian
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Re: Lets talk weight reduction

Postby Fasterthansome » Sat Nov 02, 2013 2:25 pm

Thanks for the replies. I am going with a Overkill rack and crossmember and cutting the front end out as much as possible should be good for a decent amount of weight. Got the garage organized a bit today then cut 10 lbs out of the car :th: Had to start on it and 10 lbs is 10 lbs.
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Re: Lets talk weight reduction

Postby 80 MONZTA » Sat Nov 02, 2013 5:21 pm

Just weighed my stock hatch with glass, 55 lbs.
The rear bumper, just the aluminium inner and lower urethane part is 33 lbs, did not weigh the upper urethane and the crash absorber parts.
The fiberglass part under the urethane nose with the four headlights still attached weighs 13 lbs, I think most of that is the headlights themselves.
Is your car still street legal - headlights, turn signals, wipers etc?

I am lightening mine also, but it is still a street car. So I am not sure if it would be a good idea to loose the bumper aluminium, or just cut a bunch of holes in them. I have an extra front bumper, so I already cut the front brackets in half and will put some holes in the aluminium part next. Then weigh both to see if it was worth it or not.
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Re: Lets talk weight reduction

Postby Fasterthansome » Sat Nov 02, 2013 7:48 pm

The car is street driven occasionally but not sure how much in the future. Still has lights turn signals but no horn and wpiers and motor are out of car. Looks like I can get some weight out of the hatch and rear bumper. Spent some time looking over the car today and see many places a hole saw can trim some weight.
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Re: Lets talk weight reduction

Postby Fasterthansome » Sat Nov 02, 2013 7:50 pm

stage169 wrote:Didn't know if you have seen the Jegster front end before? http://www.jegs.com/p/Jegster/Jegster-V ... 3/10002/-1

Chop approximately 200 pounds off so they say.

I liked how Bill tied his bars to the stock suspension. Keep us posted on what you finally end up doing I'd like to see the build :th:

Brian

I looked at the jegs front clip but would like to keep stock front clip as many classes require it. It looks like I can trim it down a bunch.
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Re: Lets talk weight reduction

Postby anorexicvega » Sun Nov 03, 2013 11:12 am

I've read several places that say the 71-73 vega weighs 22-2400 in stock trim depending on body style and options. Is this info incorrect?
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Re: Lets talk weight reduction

Postby Fasterthansome » Sun Nov 03, 2013 11:36 am

If its accurate thats light :D Too bad I have a heavy Starfire.
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Re: Lets talk weight reduction

Postby anorexicvega » Sun Nov 03, 2013 5:00 pm

Fasterthansome wrote:If its accurate thats light :D Too bad I have a heavy Starfire.

6.5 How much do the H-bodies weigh?
Vega:

1971-1972: 2146 to 2333 lbs (sedans are lightest, wagons are heaviest)
1973-1974: 2219 to 2404 lbs (new bumpers)
1975-1977: 2415 to 2571 lbs (more smog equipment, general bloat)

Monza:

The Monza varied from 2700-3000 lbs depending on options. All Monza-based models came out after the "big bumper" regulations and emissions regulations, so the weight doesn't increase much over the prodution run from 1975-1980.
To give you some idea of how options add up, here is some information from the 1978 GM Dealer's Guide (in pounds):
Curb weight - full gas & fluids w/4 cylinder engine:
1HM27 2-dr notchback coupe 2726
1HM07 2-dr hatchback coupe 2782
1HM77 2-dr hatchback coupe 2695
1HM15 2-dr station wagon 2754
1HR27 2-dr notchback coupe 2781
1HR07 2-dr hatchback coupe 2823

Add the following weights for these options:
A/C L4 Engine 60
V6 Engine 61
V8 Engine 85
Floor Mats 6
Power Brakes 8
Power Steering 34
Stereo w/Tape Player 11
Wheel Trim Rings 6
3.2 liter L6 71
w/3spd auto trn 12
3.8 liter V6 70
w/3spd auto trn 12
5.0 liter v8 275
w/3spd auto trn 10
LX6 engine 0
w/3spd auto trn 19
w/5spd tran -16





I hope these numbers are pretty close, i've been basing my build off the 22-2400lb figure.
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