Doing some weight math

[The Atomic Ass]

I used to have a 1990 Pontiac Sunbird, that I junked minus the entire drivetrain, exhaust, cooling, and battery. The junkyard weighed it out to 1,980lbs. Factory curb weight was supposedly 2,502.

Does that sound about right for the removed components? And how much lighter can a car that general size go by stripping out needless stuff like plastic interior bits, carpeting, headliner etc?

I'm hoping to make a 5-seater electric with lots of usable trunk space that weighs in less than 2,500 curb. I don't plan on starting with a Sunbird chassis, but I'm following the general size of it.

[SuperTrooper]

Interior bits weigh very little. When I stripped the interior of my '83 Mustang GT to go bracket racing years ago, the entire package (including the dash, A/C, power window motors) only dropped about 150 lbs.

For useable space in a chassis look for small wagons (Focus, Cavalier, Saturn).

[jamesqf]

Right that the interior stuff doesn't weigh much, and we could have a nice discussion about how much of it is actually needless. Most of the weight is going to be in the sheet metal, which is why you see articles about fiberglass/foam body building techniques. Or you might look here for ideas on stripping out unnecessary weight: Kinetic Vehicles

[The Atomic Ass]

Originally Posted by SuperTrooper

Interior bits weigh very little. When I stripped the interior of my '83 Mustang GT to go bracket racing years ago, the entire package (including the dash, A/C, power window motors) only dropped about 150 lbs.

For useable space in a chassis look for small wagons (Focus, Cavalier, Saturn).

I was actually going to go custom-chassis on this... Plus, a wagon would not gain me any usable space over a sedan. I wouldn't quite fill out said Sunbird's trunk with my current needs. Though, I may go the hatchback route.

Also, I'm going to try to get as close to a tear-drop as possible, and a hatchback actually takes the closest to it.

[wagonman76]

The weight sounds about right for a Sunbird.

[Blue Bomber Man]

If you are custom building your own chassis I'm sure you could get under 1500 pounds if you pushed the envelope enough (Including drivetrain and batteries). If you really want to be cost effective I would size it similar to a Mazda Miata. The weight and reduced CdA will help substantially. Even better would be 3 wheel design to get around most regulations to register the vehicle.

Keep in mind that Aptera's 3 wheel vehicle has a very low Cd of about .13 if I remember right and I'm sure it's weight is around 1100-1300 pounds. Their battery pack is something like 15kw-hours or more for a range of about 100 miles I think (just grabbing numbers from memory). So if you are less aerodynamic and heavier you would need to adjust your battery pack size or range expectations accordingly.

Good luck!

[JQmile]

5 people=600+ pounds, so you have to factor that in as well if you are going to be using your car as a people hauler. Drag racing stuff is really light, but may not be up for daily city potholes.

If Memory serves, these struts from strange (( Strange Engineering Catalog ))weigh less than 15 lb complete with brakes and springs. Just need to mount em, then get a lightweight rack a pinion unit...etc....

I've seen altered style drag cars come in below 800 pounds as a rolling chassis, and they are a 125-inch wheelbase or longer. Just depends on how much money you have an how important weight is to you.

I'd say a weight between 1500-2500 is realistic depending on how hard you're trying and how much aluminum, magnesium, and carbon fiber you can afford.

[Blue Bomber Man]

The TREV has an interesting approach to saving weight using honeycomb aluminum core panels which come in sizes of 2400mm x 1200mm with a thickness of 10, 20, or 30 mm. They are very strong but fairly expensive at around 200-250$ a pop. would need anywheres from 4-12 panels depending on the size of the vehicle.

I am putting up a resources post on my blog that includes information on these panels as well as the construction methods for them (very easy to work with, only handtools required!)

Good luck with your build... if you need any autocad designs I might be interested in helping... No charge for anything simple enough but donations are always accepted! =)

[ATaylorRacing]

I took 70 lbs out of my Geo Metro. The passenger seat and bolts were 32.

I drag race a 84 Horizon and it is also street driven, got it down to 1710 lbs, but added a radio, heater, wipers, and thin carpeting to make it more road worthy. The sound deadoning under the carpet was VERY heavy as was the dash. I also use lexan on the rear doors and hatch and replaced the sheetmetal where the spare tire used to be held with thin gauge aluminum. On both cars I replaced both wipers with a single longer one on drivers side.

The Geo with a full tank of gas (baby seat, baby toys, and baby bag) is 1730 lbs, but I drove it to the drag strip and took out the baby seat, baby toys, baby bag, and did not fill up the tank. With a 1/4 tank of gas it then weighed only 1660 lbs. I am thinking of putting in a 4 gallon race fuel cell so that when full and with the baby stuff back in it the total wt will be 43 lbs less. I did the passenger mirror delete on both cars but did not like my limited view so put them back on. I am thinking of lexan for the Geo, but that costs money and I am trying to make the gas savings pay for the car.

[Christ]

The interior on a Sunbird (average) comes to about 100lbs.

Taking out sound deadening tar is another 20-30 sometimes, as well as seam sealer (re-apply caulking properly to keep seal)

The dash weighs about 30 lbs as well, you can remove most of it and replace it with FG parts.

Most of the weight on a J-Car chassis is from the suspension components. Either custom make or replace most of them with aluminum, and you're golden.


Source - I used to have a 1988 Sunbird LE and a 198x Sunbird GT 'vert Turbo.