Hi all,
Just read the thread about the weights of cars. Thought I would make a follow up thread - What have people done to keep their weight down in cars?
Whats good and what isnt? Should be a useful thread for people wanting the most from their car.
Regards
Matt
P.S. I've only just started a build so can't really add anything!! Aluminium sheet instead of steel perhaps?
Im going on a big diet!
minimum interior
smaller wheels
no windscreen and with a bike engine should see you inbetween 430kg and 490kg
First thing to do is to ditch the car engine and get a lightweight bike engine. 
Second place to look and start saving weight is on the unsprung and
rotational mass ie, wheels and tyre combination, brake discs and calipers and uprights. You can also save some weight on your choice of diff and
driveshafts. The list goes on and on.............
Phil
Light weight battery will loose a bit more.
Light weight seat., No passenger..
Visit the lav before you go out for a drive
quote:
Originally posted by matt.c
Im going on a big diet!
minimum amount of wiring and dials , no carpets , interior etc.
keeping your rolling stock as lightweight as possible , soild discs etc , single piston calipers .
single gel coat and woven roving GRP , pretty cheap lightweight car .
Lose the pinto
lightweight wheels
solid discs not vented
CFRP bodywork instead of GRP
thinwall T45 steel for the chassis
smaller fuel tank
unpadded seats
no boot box
cutting off the excess length from the suspension bolts will save a kilo.
I've done none of these, except for the pinto.
Carbon fibre floor / rear panels / body work, muffet diff, magnesium 13" alloys, titanium bolts.
My ar*e, now stop dreaming and learn to drive faster
Round tube, small wheels, Ali floor and panels, bike battery, engine & dials.
If you pick it up and it feels heavy put it down and look for a lighter item.
Stength is in design, lots of triangles not thick lumps of metal !
Even simple things like using correctly sized bolts makes a big difference when added up.
Regards Mark
This reminds me of the classic "Sevens" list topic about saving weight.
To summarise, men with necks like birthday cakes were disscussing wether it was worth drilling the centres out of bolts to save a quarter ounce.
Eat less pies.
Cheers
Chris
As said previously rotational weight is the 'best' kind to lose.
Proper racing lightweight wheels in a small size probably 13" [i.e. not halfords budget 18" ]
Decent lightweight tyres, do some research.
Solid discs rather than vented.
Also
Alloy calipers
For bonus points put the engine in the boot to avoid the penalty of the driveshaft and separate diff/gearbox casings.
quote:
Originally posted by dave r
quote:
Originally posted by matt.c
Im going on a big diet!
me and you both ;p
quote:
Originally posted by chrisg
To summarise, men with necks like birthday cakes were disscussing wether it was worth drilling the centres out of bolts to save a quarter ounce.
Eat less pies.
Is the formula pie/arse squared? Apart from the fitting solid disks which will actually be cheaper every other option apart from the diet seems to be very expensive. What about leaving the brakes off, that should save a bit, and put IRN-BRU in the radiator, the bubbles will weigh less than liquid. Shave your head, have your teeth out and any bits you can do without could be removed, come on how long is it since you used it and it just looks silly dangling there. My mate lost 2 stone when he had his leg off, how dedicated are you?
1. don't paint the body panels.
2. drive without alternator; you'll need to figure out how far the battery on its own will take you (not a good for long road journeys).
3. use a bus system for the electrics with chip control for the lamps to minimise amount of wire used.
[Edited on 19/12/06 by 02GF74]
quote:
Originally posted by chrisg
This reminds me of the classic "Sevens" list topic about saving weight.
To summarise, men with necks like birthday cakes were disscussing wether it was worth drilling the centres out of bolts to save a quarter ounce.
Eat less pies.
Cheers
Chris
And only three months to do it. It's gonna
be a starvation Chrissy for me. ) 
Decide what you want to use the car for first - if it's track blaster then go the mega lightweight route - if you want an all weather long distance machine then think again......
quote:
Originally posted by chrisg
This reminds me of the classic "Sevens" list topic about saving weight.
To summarise, men with necks like birthday cakes were disscussing wether it was worth drilling the centres out of bolts to save a quarter ounce.
Eat less pies.
Cheers
Chris
quote:
Originally posted by Syd Bridge
I'm trying to lose 20kg's from my racecar build, -----------mainly from around my gut!
Cheers, ( Mines a fizzy water
Syd.
some food for thought on keeping weight down. The most important areas for weight reduction are in unsprung weight. The lighter the overall weight,
the greater the effect of the unsprung weight on the handling of the car.
One of the most overlooked areas for weight reduction by amateur builders is also one of the most important.I'm talking about wheels and tyres.
On my car, an Alfasud Sprint, the standard wheels and tyres (5.5x14 and 185/60) weigh in at 18kg a corner. Replacing them with old 7x13 Allycat rally
specials which cost me a tenner each and a set of 7x21 Avon acb10s (part worn 65quid a set delivered) lost 7kgs a corner. If you also consider that
because they are rotating they effectively add another 1/4 of their weight to the rest of the car it adds up to carrying an extra 35 kgs or so or to
put it another way the weight of an extra gearbox!
I had no idea that there was such a weight difference until I put them on the bathroom scales so think about that before buying alloy hubs to save 1kg
a corner!
quote:
Originally posted by hughjinjin
If you also consider that because they are rotating they effectively add another 1/4 of their weight to the rest of the car ... so think about that before buying alloy hubs to save 1kg a corner!
my point is that it is better spending your money on reducing the weight of the wheels and tyres than on the hubs because there is much more weight to be saved
Re the diff. Go for a freelander diff. Its lighter than a standard Ford item.... Not as cheap though.... Quaife do a LSD for it too which is certainly
a wallet-lightening exercise...
Otherwise it's just ali floor panels, bike engine , alloy uprights / callipers etc as previously mentioned.. Nicad battery (or at least
motorbike battery)....
Drill f'ing big holes in the passenger footwell firewall and plate over the ali (have you seen how thick the metal is sometimes!?!) or if
you're DIYing the chassis only put battleship grade steel on the driver side firewall for the pedals.
If you want to go really light get drilled and grooved brake discs... When the cracking around the holes gets really bad and the disc explodes they
don't way anything
Anyone know how much weight IRS saves overall? Obviously the unsprung weight is the primary reason, but wondering how much heavier a solid axle would
be.
Cheers.
quote:
Originally posted by C10CoryM
Anyone know how much weight IRS saves overall? Obviously the unsprung weight is the primary reason, but wondering how much heavier a solid axle would be.
Cheers.
quote:
Originally posted by Stu16v
quote:
Originally posted by C10CoryM
Anyone know how much weight IRS saves overall? Obviously the unsprung weight is the primary reason, but wondering how much heavier a solid axle would be.
Cheers.
An 'average' Sierra based IRS setup is actually heavier than an Escort Mk2 live axle...
Are the sierra diff and uprights aluminum or iron?
My viable options are a 7.5" ford axle (very similar to a capri Id guess), or a custom SLA with MX5 miata diff/uprights.
I like the 7.5" in that I am familiar with a 4link setup and won't take a lot of time to deal with, but it is heavy (component, and unsprung
weight). Other choice is to spend countless hours obsessing about the geometry of a SLA setup. I figured the mx5 stuff would weigh in a little
lighter over all, but never actually verified that. Only real goal Ive set on my budget build is a curb weight limit. Everything else is
secondary.
De-dion isn't commonly used here. I would personally opt for IRS or live axle but lets start another topic if its going to end up a can o'
worms .
Cheers.
The sierra diff is in an alloy casting but the uprights are in cast iron.
quote:
Originally posted by robertst
yes but its not unsprung mass just like a live axle is... so theoretically an IRS based car handles much, much better than a live axle one.
on a smooth road a live axle works very well it just when it gets bumpy that the irs really start to show an advantage. there are alot of very capable live axle racers out there
I lost 13kg's this year....
Cheapest performance upgrade I have ever made...
Well I don't know about others but here is what I did
Magnesium Alloy Wheels with Toyo R888 tyres
Carbon Fibre Propshaft
Titanium Drive Shafts
7" Sierra Diff rather than 7.5"
Carbon Fibre Seats
Alloy Brake Callipers all round and front dics's with alloy bells
Exedy Hyper Carbon Fibre Clutch,Light Weight Flywheel and Alloy Cover
Braille No-Weight Racing Battery
Electric ceramic Heater.
Titanium exhuast with Carbon Fibre can.
As I'm sure you can tell this has turned out to not be very locost. Would I do it again..short answer is no.
That's the problem, you rapidly get into diminishing returns on stuff like this. Yes, the first 15-20kgs can be saved with different component choices when building, but most extra stuff starts to cost loads of money! To start with, ally panels and light wheels are easy to sort, and save a reasonable amount of weight, but using Ti bolts and shafts, CF prop etc, these things do save weight, but not much compared to their cost! Sub 500 kg is plenty for a road car, otherwise just lose some weight, I know I need to. That's 20 Kg for free, and the lady's will like you more too!