Weight
Probably the most underrated and underutilised mod that we can make in my view. Weight has a huge effect on the realworld performance and economy of your car. Now you are probably all wondering if I’m hinting that you should go on a diet. Well maybe it isn’t such a daft idea but I was more referring to the car!
Many performance orientated folk think of power to weight ratio rather than outright power measurements. Ok you don’t get quite the same bragging rights at a rolling road, but put on a track a 130bhp car that weighs 1200kg against a 130bhp car that weighs 900kg and the performance difference between them will be huge. That’s why things like the ariel atom are so fast, power to weight ratio is where it counts on most short circuit tracks.
So what can you do about putting your car on a diet. Well that depends on how seriously you want to take it. If you are using it as an everyday car then there probably isn’t a lot you can do without compromising. If you are building a car purely for performance, and to hell with the practicality then you can usually shave 150kg off of most cars sometimes much more.
First things to go are the interior seats, trim, spare wheel, and any unnecessary kit e.g. aircon. Then there are the windows which can be replaced with Perspex. Pretty much all the door trim and sound deadening can be lost too. You can even remove most of the dash and probably half of the wiring too if you really want to get serious about it. Lastly you can think about lightening the car components themselves, fibreglass/carbon fibre bonnets, boots, doors, smaller battery alternator etc. It all depends on how car you want to go. Some people I know have even cut holes in non structural bits of bodywork to lighten them!