The Weight Saving thread!

[ChrisPears]

Hmm! That's an idea!
Seriously though, it'll be easier to take a little bit of weight from lots of places rather than lots of weight from a few places. I was amazed at how heavy the bonnet is for example, so with a little creative angle grinder work to the inner skin, I'm sure there are a few pounds to come out of that.

Any more suggestions? Doors?

Ok...weight saving...off the top of my head:

If you start cutting out the support structures from the bonnet it'll flap in the wind as drive down the road, and deform easily. Proper weight saving is expensive, fibreglass/carbon/kevlar panels (bonnet, front wings, door skin and tail gate) will all save major weight, but will cost a bomb if you can even find them. For the doors, you'll probably want to keep the frames and bond the light weight skin onto it, so they don't flap in the breeze. Doors should probably only be done if you have a full roll cage in for rigidity and safety.

Ditch all the standard seats and replace the fronts with bucket seats - fixed back ones for major savings.
Gut the interior, replace the dash with just an instrument pod
Get rid of all the extra electrics in the car, and strip the wiring out
Ditch the heater matrix and blower fan, you'll even carry less coolant around then - but you do require a method for clearing the windscreen for MOT.
Take all the underseal off from under the car and replace it with Por15. Spend a while with a hot air gun melting all the wax out of the crevaces
Polycarbonate (or similar) windows - that rear screen must weigh a tonne
loose the bumpers - they're not a legal requirement...but I think you'll have to loose the tow eyes as well
Reduce unsprung weight by going for alloy brake calipers (4 pots probably), coil overs and light weight alloys
Move the battery to behind the passenger seat to even out the weight distribution a little
Carefull selection of exhaust materials
Rust - Natures weight saving.

Once you've done all that, and you still want lighter, things start getting silly:
Half size fuel tank
Cut the spare wheel well out and replace with a fibre/carbon panel
Take a hole cutter to anything not structural
Cut the roof skin off and replace with an aluminium panel (not recommended)

After all that, the resulting car could be down to about 750 - 800kg, but it won't be the most comfortable ride, and you'll have spent a fortune. Would be fun though.

[steve]

What are you using the car for? Why are you lightening it?

If you're planning on competing, there may well be rules and regs that govern which bits you can and can't alter.

If it's just for track-days, there won't be any limits, but you will need to be sure your car is safe in the event of a major accident.

For either of these, weight distribution is probably as important as total weight (maybe more so) - most of your speed that isn't solely down to how much power you have will be lost in the corners.

If it's for the road at all (even if mostly for track days) I wouldn't go much beyond taking out the non-essential interior and trim.

Couldn't agree more, good balance is way more important than light weight. Plastic bonnet and wings and stick your battery in the boot would probably make a good start.

[Nate]

my old housemate had a volvo 740 saloon. it went on the slimfast plan to see if that would make it beat my astra on a drag race up and down the bingley bypass.

started with the easy stuff - rear seats, carpet and sound deadening, door trim panels, half of the dashboard, all the centre console, but it wasn't enough. so the complete sunroof mech came out (slide and tilt steel one) and the hole made good by sticking a bit of acrylic sheet to it with no more nails, the metal girders in the bumpers came out, the side and rear windows all replaced with plastic, all the window mechanisms apart from the drivers door went. then out with the hose saw and started on the bulkhead between the cabin and the boot.

all in we stripped over 350kg off it, taking it to a kerb weight of under a ton!

never got to find out if it would beat the astra though, as i had bought the rocco by then

[Deako]

Hi all. I havent had my new track car on the weighbridge yet, however, i cut the bumper irons out today and put the bumpers back together with the original 2x support brackets and a couple of stainless bolts to hold the bumpers on to them. I will weigh the bits tomorrow to tell you how much that saved.


IMG_2220 by LukeDeakin, on Flickr

My car is already completely stripped and caged. I will be looking at other ways to lighten as well. I will be replacing the rest of the glass with lexan (front windows already done), and will also be replacing the seats with some slightly lighter ones as well. Still deciding what to do with the door cards. Will probably use some thin lexan. Although i personally dont think they are all that heavy with everything else stripped off them.


IMG_2213 by LukeDeakin, on Flickr


IMG_2214 by LukeDeakin, on Flickr

My doors have also had some of the metalwork cut away from them internally. But there is more to come off quite easily. I will get busy with the angle grinder tomorrow. ;)

[MikeH]

I've just been doing the same as you on the bumpers Luke - Saved between 5 and 6 kilos by doing the front and rear bumper.

Also, from the work I've done this week, There's about 7kg of tar on the inside of the floor. I removed it with an air chisel. I managed to make a couple of holes in the process, and welded those up, so be careful out there, kids ;)

I've also chopped out the insides of the doors, and fitted 3mm polycarb windows in the original runners. I'm looking for a way to replace those runners with lighter ally ones, as they're pretty heavy.

The rear spoiler/wiper and big battery went some time ago, saving about 8kg each.

The sunroof was removed too. The bits I took out weighed 15kg, including chopping out the cassette from the roof.

I've also gone from track wheels that weigh 8kg each, to some that weigh 6.5kg each, so that's 6kg off the car, as well as a reduction of rotating mass and unsprung weight.

I expect I saved a couple of kilos with the change from Kjet to Megasquirt, but I didn't weight the bits.

Unfortunately...
- the roll cage weighs 25 or 30kg
- the GTD radiator is a kilo or two heavier than the standard one that was on there.

[steve]

I tend to just burn underseal off.

Make sure you've got appropriate fire fighting equipment to hand (Karcher make some good ones cunning disguised as pressure washers), and you keep away from stuff that's got petrol in it

[Cpt Custom]

Hi all. I havent had my new track car on the weighbridge yet ...

Neat. Is that the one that was up for sale a few months back on ebay?

[Deako]

Hi all. I havent had my new track car on the weighbridge yet ...

Neat. Is that the one that was up for sale a few months back on ebay?

Cheers. It was only about 2 weeks ago actually. I had spotted it and was really interested, before i noticed Funky putting the link up on here. I collected it from Scotland on Good Friday. 12 hours driving in one day.

First real outing is at Curborough tomorrow. Hopefully get some nice pics.

Today i cut some more holes out the front bumper, removed the passenger seat and door bar from the passenger side. All counts for the event.

[Rusty dan]

Lots of good ideas here peeps, I am all for weight saving being a drag racer so will be implementing some of them for the white lady.
I will weigh mine race ready and see what I have saved :)

[Funky Diver]

If you have a full cage, do you really need a full metal floor or could you not remove sections of that and replace with another material? GRP / polycarbonate, etc.

For example, under the seats, in the footwell where your feet don't rest. Obviously strengthen where you're taking out.

If you were REALLY serious of course, you could always get a GRP body tub made up

[the edmundator]

If you have a full cage, do you really need a full metal floor or could you not remove sections of that and replace with another material? GRP / polycarbonate, etc.

Depends what the cage is mounted to. Unless it braces between all four suspension turrets, I wouldn't remove anything that braces or provides strength for the original chassis design.

[Rusty dan]

Is there not a new law surrounding changes to the monocoque?
If any part of the monocoque is changed, an SVA test needs to be done on the car which involves point scoring depending on what has been done....

Of course if you dont plan to use on the roads, dont worry lol

[Funky Diver]

Not as far as I'm aware....

http://www.direct.gov.uk/en/TravelAndTr ... /DG_069869

It may well just be internet chinese whispers.

[Rocco Horror]

Some really good ideas here. I love the track car - very clean and tidy, just as a racer should be! Keep them coming!

[Funky Diver]

http://www.clubgti.com/forum/showpost.p ... tcount=204

For rear screen replacement in polycarbonate :)