Laws:
The dutch laws regarding this subject are not that complex. here are the most important ones:
- The front windscreen is not allowed to be made from lexan or polycarbonate. This because of crash safety during crashes. All other windows can be made from lexan/polycarbonate.
- If you are performing a top chop, you do not have to mention this to the RDW. The only point to fail an apk is the quality of the welds. Just pay attention that with a top chop you usually lose strength so it is a good idea to install a roll cage.
- Front fog lights are not mandatory. Rear fog lights are also not mandatory for cars before 1998
- Side repeaters are not mandatory for cars before 1998
- According to the rdw a car is made out of 3 parts: the body, the suspension and the engine. 2 of the 3 parts should be the same as mentioned on the vin number to pass apk. If not you can register it as a kit car.
- A car is allowed to drive without bumper, as long as there are no parts sticking out. The rule of thumb is that when you look straight above the car and you see nothing sticking out, its legal. It is a grey area though and removing bumpers is usually not good for the aerodynamics. Removing the rear bumper is good for aerodynamics, but bear in mind that you will be stopped by the police a lot as it looks like you have just crashed your car.
- Airbags/ABS should be working if installed. removing them will have no concequences for APK
- The blower for the front wind screen should be working, for the rest there are no regulations regarding the heating of the car. Installing a 12v blower or blowdryer is legal.
- All interior parts are allowed to be removed as long as there will be no parts sticking out which could hurt the driver or passengers.
- The car should have a right mirror and a rear view mirror or a right and left mirror.
- Using carbon fiber is allowed, as long as it does not affect the crash zone like doors for example.
The most important aspects to reduce weight:
The most important aspect is that just removing everything is NOT better for your car. For example; a lot of people get rid of the rear interieor of the car, and mention that their car is faster. This might be true as the acceleration numbers are higher, but as the center of gravity has shifted towards the front and the crx already has a light rear end it has led to a result that the maximum corner speed has lowered. The car is now also more sensitive to fluctuations in the corner speed. If you want better times with your track crx then it is a smarter idea to keep the rear interior..
So if we look at that same crx it is more sensible to remove weight at the front (lightweight radiator, carbon headlights etc.) This will result in a more stable car as the center of gravity has moved towards the rear.
Changing the center of gravity us usually the most important thing to remember when getting rid of weight in the car. So you would theoretically have more benefit from replacing your targa roof by one made out of carbon than getting rid of your carpet, even though you will probably save the same amount of weight. This because you will lower the center of gravity because of this. (however, replacing the targa for a carbon one would result in a less stiff body, depending on the body type.)
Weight reduction per racing type
Timeattack
For time attack it is important to have a low center of gravity. If you want to lose weight you can better get rid of the things that are mounted high up in the car. Getting rid of your moon roof is a good idea for example. However the mods should not make the car instable. Adjusting the suspension will also have some positive advantages, but we will continue more in a next topic. Removing parts like spoilers is also not that smart as it is not good for the handling.
Drift
For drifting there are several points. A beginner can better start by putting the center of gravity towards the rear. Because of this the car will oversteer more and break out easier. The more experienced driver would prefer understeer, so then it is better to install a carbon fiber boot for example.
The center of gravity is the same, a beginning drifter would have more benefit with a higher center of gravity, while the more experienced drifter would like to have it lower.
Drag
For dragracing it is the easiest to lose weight as the center of gravity id less important. You can just remove as much as possible, and it does not matter wether this is on the front or the back. With most cars this is compensated by springrates, so it does not really matter wether the center of gravity is more towards the front or the rear. Th best is to have it at the front, so the wheels have the most grip during acceleration and the car will not flip as easily.
As you can see there are a lot of aspects to take in consideration. There is never a perfect way to do this, as it is all dependant on your driving style. But keep on mind that the above mentioned tips will make you able to adjust your car a lot better.
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