Even cars several decades old can be chock full of heavy creature comforts, many of which you can bin to save weight. Say bye bye to the air conditioning compressor, and that’s around 5kg gone. A further 10 or more kilos can be shed from removing the heater matrix, fan and associated piping. The stereo is a prime target too, along with all the speakers and wiring.
The things you can’t do without can then be swapped for lighter versions. Car batteries - for instance - typically weigh around 10-15kg, a figure you can half by switching to a smaller race battery.
This is where you can make some serious free reductions; it’s just a question of how far you want to go. Assuming you’ve started with the obvious - removing any random crap you don’t need in the car, ditching the spare wheel and jack etc - you can then look to take out the carpet, underlay and rear seats. Depending on the car, losing the rear seats could save you around 25kg, and that’s before you turn your attention to the front chairs.
If your car has electrically adjustable seats, they could weigh as much as 35kg each. In an ideal world, for maximum because race car-ness, you’d ditch the passenger seat entirely, and swap the driver’s seat for a sports seat tipping the scales at around 12kg. This will give you a total saving of almost 60kg.
Want to go further? You can expect to shed a further kilo or two by taking off the door cards, or over 10kg by losing the dashboard.
If you’re really serious about shedding the kilos, consider swapping steel or aluminium body panels with replacement items made from GRP (glass fibre-reinforced plastic). The bonnet, front wings, boot lid, doors and even the roof can be swapped for GRP, giving your car significant weight savings.
Want an example? The plastic £175 BMW E36 3-series bonnet you see above (from Geoffsteel.com) weighs just 3kg, compared to 15kg for the factory metal item. Of course, you can also make savings by swapping for much stronger, better fitting carbonfibre body panels, but they’re more expensive: if you wanted a carbon bonnet for your E36 instead of a GRP one, you’re looking at more like £500.
While you’re at it with the plastic swapping, it’s worth thinking about switching out your glass windows too. Using polycarbonate instead can drop 1-2kg for each window replaced, at a cost of around £70 for a pair of front windows.
By swapping to a lighter set of wheels, you could save yourself around 2-3kg a corner. Doesn’t sound like a huge amount, but the benefits go further than just cutting down the car’s overall weight figure. Reducing rotational mass of the rims means that the suspension doesn’t have to work quite so hard, and you’ll see small improvements in acceleration, as it’s easier for the engine to spin lighter wheels.
For short track days stints, shorter races and less adventurous road drives, you don’t need to be lugging around a full tank of fuel. Fill your 55-litre fuel tank only half way, and that’s 27.5 litres of unnecessary liquid you’ve lost - the equivalent of about 20kg. Sounds obvious, but it’s one people tend to forget.
Apparently, around 60 per cent of adults in the UK are either overweight or obese. So, if you’re around three stone overweight let’s say, that’s 19kg you could shift for free. You’d have to shell out hundreds of pounds to drop that amount through the use of something like GRP body panels.
Then you have to consider the weight of a whole human being. Is your mate asking for a lift? Tell him to walk. Even if they’re not substantially built, that’s around 70kg saved right there…
Note: this is by no means an exhaustive list, and all weights are approximate and will vary from car-to-car. If you’re ever unsure about a particular job, talk to a professional before attempting it!