This week we are talking about making your car light! Yeah, most of us already realized that a modern heavy car, can’t compete with the lightweight rockets from the past. I’m trying to divide that in 3 sections. We can call it Stages 1,2 and 3, but I rather call it the evolution: “Street”, “ClubSport”, “RaceOnly”.
Most cars barely see a track, but people still enjoy driving them on the street. At this point you only want to remove the stuff you really don’t need!
The fifth wheel and the jack system is worth to remove and replace it with an inflator spray. This already safes you at least 15 – 20kg. It’s not much, but in an S13, S14 it’s 2 – 3% of the cars weight! The next step is we can install a lighter dry battery, which will be another 3 – 4kg. Modern batteries are lighter than the classic wet-lead units! The next step should be, if you live in a not so hot climate zone, remove the AC unit!
The S13 full setup will weight 26kg. With compressor, evap unit, hoses etc. If you have removed this, it’s a nice thing because you also safe some parasitic hp loss on the engine due to less drag! Get some decent rims and an aftermarket suspension setup and you should be down by 50kg! This is already nearly 1 driver less in the car!
This evolution step is still drivable on the street but you will only enjoy the car if you really push it. The daily abilities are maybe a bit restricted or uncomfortable. We start this step with ripping all not necessary things out of the car. Seats, carpets etc.
At this point you will install a rollcage or rollbar for personal protection. Unfortunatly a good rollcage will also bring 40kgs back to the interior, but by replacing the front seats with Recaro or Sparco units you will also safe 20kg just with that! The rear seats and all isolation mats will bring another 20 – 30kg depending on car. The clue here is, that you can mess with the balance, because the car, especially the rear, is now very light, whereas the front is still very heavy. Relocation of the battery to the rear also won’t harm at this point!
Depending on your passion, your choice and the car you will have a lightened still streetable racecar. It’s up to you how extreme you like it! With a rollcage installed a weight reduction of 60 – 80kg is realistic. This is already a lot and the car has better protection and is a bit stiffer than the original one!
Well the most important thing at this point is the budget. You can bring the car down to 0 kg with an infinite budget. Yeah sounds unreal, but the limiting factor here is really the amount of money you’d like to spend! You can still lighten your electronic harness and maybe remove some weight by cutting the panels, but this will be very time consuming and can cause some trouble with the electronical system of the car! But the big weight savings at this point will come from replacing parts!
A carbon hood, trunk, doors can already safe you 60kg, because most doors are really heavy due to side protection! The windows can be replaced by lexan units, which safes also a lot of weight. The limit at this point is really your budget. It can go as extreme as building all panels out of carbon fiber and cut down the weight to the minimum! As an example here the OEM EVO 9 weights around 1450kg dry. The HKS CTR230 is quoted to be 1070kg most probably with driver. This is over 400kg less than the standard car!
To finish this up I have to say, that most boy-racers just remove weight in the rear because the “empty”-looking car is not nice to live with. But if you are serious about trackday driving, racing – you should elaborate a plan and work from there. Sometimes 10kg more is better if the balance is good, but you can always throw weight back in there. It’s easy to remove stuff in the rear, but it’s very hard to make the front lighter!
All in all removing weight is probably the most cost effective way to cut you lap times or get a better weight/power ratio. Removing weight will not also make you faster during acceleration but also during braking or cornering. So it helps actually more then just adding power.