Weight reduction

alltrbo · Post by **alltrbo** » Wed Apr 05, 2006 12:06 am

For mid-engine, no luggage roomed 2 seater micro-machines, Fiero's are fat pigs. Fortunately this is one of the rare cases where it's a side effect of proper chassis stiffness instead of unruly bean-counter dictatorship (they're powerless and can't handle because of that). All reasons aside, they're still fat pigs for what they are. So how do we get them to mold into the sportscar-like state of weightless nirvana that they deserve, without killing off the only good reason that they're so obese?

Anything from "remove the ashtray in your daily driver" to "mold the windshield rearview mirror housing out of carbon fiber" to "cut off everything except the space-frame, a seat, wheels, and the engine" will suffice.

One thing to keep in mind is that the little things add up. I shed 85lbs from the Camaro by removing or changing relatively minor pieces, and it has lots to go. Are there any obvious small parts, as well as large chunks of weight that can leave a Fiero?

Discuss.

Shaun41178(2) · Post by **Shaun41178(2)** » Wed Apr 05, 2006 12:21 am

Buy a carbon Fiber decklid. There is one in the mall for $500. Can save you 20 or so.

product1620 · Post by **product1620** » Wed Apr 05, 2006 12:23 am

HA, love the new sig, anyways back on topic you might try going with a smaller or lighter battery, I heard of a guy running a civic off of a sport bike battery. also you could take out the spare tire, remove the trunk, take out interior trim and carpeting, and get light weight rims.

Post by **eHoward** » Wed Apr 05, 2006 12:34 am

that would be me.

product1620 wrote:, I heard of a guy running a civic off of a sport bike battery.

alltrbo · Post by **alltrbo** » Wed Apr 05, 2006 12:37 am

That CF decklid looks to be a very nice pi-ece. I'd love it, but that's not happening anytime soon. :/ Cost is a factor in reality, but doesn't have to be in this thread.

Pretty cool that it saves 20lbs being that the fiberglass hood on my Camaro only saved 22 over the stock steel scrap. It is a 2-pi-ece hood with a fully finished underside though.

Product, thanks.

The battery is a good idea, my friend swapped a motorcycle battery into his GSX. It runs it fine, considering he has a stock stereo and doesn't use too many accessories at once, ever.
My spare tire is already out.

That's probably the easiest one.
Removing the trunk would be a good one for a plain weekend cruiser or a racecar.
How much do you guys think the various interior pieces weigh?
Also, how much do the stock GT wheels weigh? They look like they don't weigh much at all.

A lot of these ideas will go into the not-running '84 Fire-o my dad gave me if I ever get settled enough to do it, I want to turn it into a cheap turbo SBC drag car. 500hp and somewhere shy of 2500lbs would be nice, on the tranny and everything else.

Some of the others I will eventually do to the GT, but that's staying perfectly streetable.

teamlseep13 · Post by **teamlseep13** » Wed Apr 05, 2006 12:43 am

I removed all of the interior and passenger seat, lost 125lbs.
So now with a full tank of gas, she weighs 2570lbs.
When I replace the Iron Duke with the ECOtec, I will loose another 100lbs or so.
I also plan on making a new engine cradle from some 4130 steel rect. tubing. I should be able to loose a few lbs with that.

The decklid and the front hood are heavy. Relaying them up even in regular glass would lighten them up.
The door beams are really heavy too. Replacing them with some round tubing would lighten them, and if you do it right, make them much stiffer.

When I have time and money, I will take the bare space frame passaenger compartment, build 4130 spacefram subframes to hang suspension, engine and radiator from. Carbon up all the body panels.

But thats a dream.

Series8217 · Post by **Series8217** » Wed Apr 05, 2006 1:33 am

alltrbo wrote: Also, how much do the stock GT wheels weigh? They look like they don't weigh much at all.

Oh they're heavy. Like 21 lbs each heavy.

See this thread for weight reduction ideas:
http://realfierotech.com/phpBB/viewtopi ... ht=weighed

Keep in mind my motor weighs 100-150lbs more than yours and my 88 has a heavier frame/suspension.

Also the trunk metal weighs almost 19 lbs and the carpet a few lbs as well (I didn't get to weigh the carpet on a scale like I did the metal, sorry). I remove my trunk after that thread, there's a thread on that as well. I've now added most of the weight back because I put in a plywood trunk so I could carry my tools around. Definitely leave the trunk in.. its not really worth it unless it also helps you with engine swap exhaust.

Fierocious · Post by **Fierocious** » Wed Apr 05, 2006 3:52 am

I've seen people cut the huge bars inside the doors.

bryson · Post by **bryson** » Wed Apr 05, 2006 10:10 am

eHoward wrote:that would be me.

product1620 wrote:, I heard of a guy running a civic off of a sport bike battery.

And me :afrocool:

About the trunk being 19lbs -- has anyone tried making a fiberglass trunk, but leaving the structural components (or making that out of tubing)? You could cut out all of the trunk metal and replace it with a fiberglass trunk, and weld in tubing behind the shock towers -- triangulating the tops and bottoms of the towers would be easy, it would weigh about the same as the stock structural member, and you could change the trunk shape just a bit if you needed to. Just leave the trunk seal metal at the top so that the trunk still seals and you have something to bolt the fiberglass to.

p8ntman442 · Post by **p8ntman442** » Wed Apr 05, 2006 11:21 am

If your saving weight, the sbc idea is the wrong direction. My motor probably saved me 100 lbs. But thats not an option for anyone else really. Ac components are obvious, but if you have a sunroof car, maybee a CF panel instead of glass. Switching out the headlight buckets and motors for flush mounts would work well. Also, if the damn radiator tubes werent filled with 5 gallons of antifreeze you could save some weight there, not sure how though.

Mach10 · Post by **Mach10** » Wed Apr 05, 2006 11:33 am

bryson wrote:
Has anyone tried making a fiberglass trunk, but leaving the structural components (or making that out of tubing)?

I'll let you know how it turns out.

Clearing some room for a pair of big mufflers, coring out some bone-cancer (why, oh WHY is the ONLY rust on the trunk?!).

The only problem I think I'll have to address is the heat from the mufflers. I'll probably rivet a couple of standoffs and attach an aluminum heat sheild to it. I'll also see what I can find in terms of heat-resistant resin.

The Dark Side of Will · Wed Apr 05, 2006 11:54 am

There's not a whole lot you can do to a Fiero to significantly reduce its weight and keep it a reasonable street car. There just isn't much extra.

The fibreglass trunk idea would be even cooler if you could make it easily removable. Tooling around town? Leave the trunk at the house. Going on a road trip? Put it back in.

Series8217 · Post by **Series8217** » Wed Apr 05, 2006 1:30 pm

The Dark Side of Will wrote:There's not a whole lot you can do to a Fiero to significantly reduce its weight and keep it a reasonable street car. There just isn't much extra.

The fibreglass trunk idea would be even cooler if you could make it easily removable. Tooling around town? Leave the trunk at the house. Going on a road trip? Put it back in.

Yeah, I've been talking about a removal fiberglass trunk for months.. I think its the way to go if I can figure out how to do it right. Besides reducing weight, it also makes working on the motor ridiculously easy when its out.

bryson wrote:About the trunk being 19lbs -- has anyone tried making a fiberglass trunk, but leaving the structural components (or making that out of tubing)? You could cut out all of the trunk metal and replace it with a fiberglass trunk, and weld in tubing behind the shock towers -- triangulating the tops and bottoms of the towers would be easy, it would weigh about the same as the stock structural member, and you could change the trunk shape just a bit if you needed to. Just leave the trunk seal metal at the top so that the trunk still seals and you have something to bolt the fiberglass to.

I'm working on it; that's been my plan since I cut the trunk. It's a lot harder than I expected!
Here's the problem: That trunk seal at the top is integral with the cross member that ties the strut towers together.
Problem 2: You're going to lose trunk space. The trunk opens up in size as you go deeper, so you obviously couldn't make it removable (or even installable in the first place) if you tried to take up all the room you have.
The way I'm looking at doing it now is making a fiberglass trunk that has a lip which sets over the factory weatherstrip seal metal, then projects straight downward as far as it will go.. just pull straight up to remove. It's still quite a challenge though, because the trunk seal is not in a plane...

There's a few pics here of what's left with the trunk metal out:
http://realfierotech.com/phpBB/viewtopic.php?t=2288
When I get back from class I'll post the pics with the bumper removed. May be easier to see that way.

The Dark Side of Will · Wed Apr 05, 2006 1:35 pm

Could make it multi-sectioned... little compartments on each side that go down outboard of the lower frame rails, then a center removable section that fills the volume of the stock trunk.

Series8217 · Post by **Series8217** » Wed Apr 05, 2006 5:20 pm

The Dark Side of Will wrote:Could make it multi-sectioned... little compartments on each side that go down outboard of the lower frame rails, then a center removable section that fills the volume of the stock trunk.

Aye, that's actually what I built last weekend and am using right now. I'd like it if I could just pull the whole thing out with all of the contents though.

whipped · Post by **whipped** » Wed Apr 05, 2006 5:41 pm

Why not just chop the bottom? That's a good amount of weight right there. It'd probably be the equivalent of building the whole thing out of fiberglass... and then you don't have to worry if you need to carry lead bricks back there, or worry about the fiberglass melting and tossing your tools down the highway..

:thumbleft:

Series8217 · Post by **Series8217** » Wed Apr 05, 2006 5:48 pm

whipped wrote:Why not just chop the bottom? That's a good amount of weight right there. It'd probably be the equivalent of building the whole thing out of fiberglass... and then you don't have to worry if you need to carry lead bricks back there, or worry about the fiberglass melting and tossing your tools down the highway..

:thumbleft:

Chop the bottom of the trunk and add a piece of sheet metal across?

Series8217 · Post by **Series8217** » Wed Apr 05, 2006 5:52 pm

Here's the pic I promised of what the rear looks like with the bumper, bumper reinforcement, and trunk removed.

Inspires some cool ideas for a custom rear end with a huge diffuser or engine cooling vents doesnt it?

alltrbo · Post by **alltrbo** » Wed Apr 05, 2006 6:40 pm

...why the heck do I have to log on every time I come here? (I am clicking on "log on each visit" too).

Removeable trunk, I like. I won't get rid of it permanently the GT as it has proven itself to be the only useful thing on this car. Heh. You guys keep working on that while I sit here with $2k in repairs to do to my Talon still. :thumbleft:

I know how heavy a small block is, heh. I said I wanted the drag car to have a cheap 500hp, and that's 100% the easiest way to do it. I mean; this car is already mine, I'd spend the minimum cost to convert it to a 350, I can come across low compression 350's like dirt then put some PM rods and decent bolts in it topped with better stock heads and a carb, weld up a JY diesel turbo setup, have a decently stout auto built for it, fat DR's on the rear, skinnies on the front, and that's about it. E85 would take care of octane and 'intercooling'.
Anything aside from that that doesn't need to be there can leave, and I'd bet it would still weigh significantly less than stock. At the most I'd leave lights and two seats in it, so I could drive to the track or up and down the street with the drag radials. Trunk? What trunk?

The GT is not going to ever weigh more than stock, engine included. 3400's are at least 30lbs lighter from what I hear, and the turbo setup will equal that out, but not add. 328whp has been done easy with just that (in a cavy). Beyond that comes lighter parts or missing parts.

I know there isn't a whole lot to remove, but there is a ton to change I think. How much does a stock starter weigh? Are there mini-starters available? any aluminum water pumps available (or are they)? Aluminum heads are nice, just saving 5lbs each/wheel is another 20, are there lighter tubular control arms? How much do you save with coilovers, etc... 10lbs here and 8lbs there adds up, like I said.

How heavy are stock body parts? Is an aftermarket 'glass hood actually lighter than the stocker? Are any of the smaller rebodies lighter? a CF body could take away some I'm sure. Any idea if a sunroof weighs more than a hardtop? As was mentioned, how much could you save with a fiberglass dash and aftermarket gauges? Racing seats are usually very light too. Would it hurt to make a new back window out of plexiglass? (just don't scratch it). It's flat and would be easy I think. The factory spoiler could go since it doesn't do anything anyway, heh.

I don't like the idea of removing the stout door beams, as they are quite strong according to Will, and could probably save your life if it came down to it. If you can make a replacement just as strong but lighter, that would be awesome.

I like the Ecotec. A turbo Ecotec (or even a modded N/A Ecotec) could make for a killer track engine in a 'minimal comfort' street/race Fiero (think slightly heavier Elise). That thing wouldn't weigh much at all I think.

Of course cost is the limitation for most of us, but I'm talking feasibly possible, not just economical.

teamlseep13 · Post by **teamlseep13** » Wed Apr 05, 2006 7:09 pm

alltrbo wrote:

I don't like the idea of removing the stout door beams, as they are quite strong according to Will, and could probably save your life if it came down to it. If you can make a replacement just as strong but lighter, that would be awesome.

I like the Ecotec. A turbo Ecotec (or even a modded N/A Ecotec) could make for a killer track engine in a 'minimal comfort' street/race Fiero (think slightly heavier Elise). That thing wouldn't weigh much at all I think.

Of course cost is the limitation for most of us, but I'm talking feasibly possible, not just economical.

You can make a stiffer, stronger door bar that is much lighter than the stock bit. The stocker is stamped steel, but a tubular unit could be arranged to be lighter and be much safer. All you need is the skill.

The slightly heavier elise is what im going for. After the turbo ECOtec gets installed, I will figure about 2400lbs without me and a full tank.
With 400hp, that gives a 6lb/hp ratio. Elise is 10lb/hp, McLaren F1 is 3.8lb/hp, to give some reference.

I will have no interior, one Kirkey aluminim road racing seat(12lbs), coated lexan rear and side windows, flush mounted headlights, carbon decklid, hood and sunroof insert. Adding those weights savings and the 100lbs from the engine swap, should compensate for the turbo system, intercooler and slightly larger(16") wheels.

After that, I will dream and maybe start cutting stuff up and making tubular structures. Just depends on money and time.