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Text | Goh Zhi Xuan
Photos | Editorial team,Imgur, Manufacturers

As car enthusiasts, many of us love to modify our cars, be it for performance or simply for that personal touch. Many popular modifications actually do more harm than good, let's see what they are.

Inherently, people love to customise and personalise their belongings, and this applies to cars as well. Some simply enjoy having a special, one-of-a-kind car. Then there are some who modify their cars with racecar-esque parts, only to hardpark at Kallang, spinning tales of how their mods make their econoboxes faster than lightning. With inaccurate information and unsound theories floating about the community, these result in many cars performing worse than stock despite much money and effort invested. This is why you should always spend ample time to do proper research to avoid throwing piles of cash to create an embarrassing road hazard of a car.
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1.     Lightweight crank pulleys

If you have ever gone online to research on popular modifications to improve your car's acceleration, you will surely chance upon suggestions to install a lightweight crank pulley. So, what are these lightweight crank pulleys, and how do they help? These refer to the main pulley at the end of your engine's crankshaft, which transmit power to other accessories such as the alternator. The idea is that by replacing the pulley with a lighter replacement piece, parasitic loss can be minimised, thus improving the engine's ability to rev faster and reduce the power sapped by the heavy stock item.

Stock crank pulleys are equipped with a harmonic damper, which works to counter the vibrations from the crankshaft and the lightweight pulleys are able to save weight by doing without them. Lightweight, undampened pulleys are known to cause premature wear to the internals of the engine (crankshaft bearings and the crankshaft) in the long run, and even more so in high-powered, high-revving applications. Furthermore, the effect of a lightweight pulley seems negligible when in gear, and if you want to shave off rotational mass from the crankshaft assembly, a lighter flywheel will make a much bigger difference.
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2.     Using an overly harsh racing clutch on the street

There's a reason why racing clutches are named so. Unless you have an extremely powerful engine that needs an aggressive clutch to transmit the power properly, there's really more cons than pros from using one. While there are several types of clutch that you can go for (organic, semi-metallic, sintered iron, sprung, unsprung, and others) generally uprated racing clutch will cost more than a stock replacement item. Depending on the clutch that you choose, the clutch pedal will require more effort to operate, the biting point will be more precise and clutch control now requires much more finesse.

You might think that's all fine, since you are an amazing driver and don't mind the daily left leg workout, but it really isn't that simple. Harsher clutches, such as the ones which use sintered iron friction material are really meant for track use. They are extremely abrasive, wearing off the friction face of the flywheel and are incapable of smooth engagement, making them useless on the streets. With less give in the system, they can also cause higher wear on other parts of your car's drivetrain.
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3.     Over lowering your car

The suspension geometry is affected when a car is lowered. Most cars are designed with a suspension setup that works well at the stock ride height. Depending on the suspension design, some cars can experience severe handling issues that are exaggerated as the car is further lowered. If over lowered without correcting the suspension geometry, the roll centre of the car will be lowered, increasing the tendency for the car to roll. While the stiffer springs might give a false sense of stability, the car really isn't much more capable at cornering.

Increased bump steer is especially pronounced when cars equipped with Macpherson strut suspension are overly lowered. Bump steer occurs when the wheel gains toe out as the suspension compresses. This is due to the uneven arc of movement between the lower control arm and the steering tie rod. Bump steer causes your car to pull to a side upon hitting a rut in the road, and promotes understeer in hard cornering situations. Overly lowered cars also tend to suffer from insufficient suspension travel, which will affect handling detrimentally.
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4.     Various suspension mistakes

Many consider suspension tuning as a form of dark art or sorcery, but the truth is there are simply too many considerations that affect the littlest of details. While we are no experts in this topic (we will be working for an F1 team if we were), there are several obvious pitfalls that all of us need to know, and avoid. While stiffer springs limits a car's body roll and give a reassuring feel, if they are excessively stiff, your car might hop over uneven surfaces, making it handle worse while being uncomfortable at the same time.

Likewise if your car is lowered with springs that are too soft, the car might bottom-out and ride on the bumpstops, again, worsening your handling. Pairing lowering springs which are both shorter and stiffer than stock with standard shock absorber can also cause issues as they are unable to cope with it. As such, the lifespan of the shock absorbers might be reduced as well.
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5.     Over stretching your tyres

In recent years, the trend of 'stancing' cars is gaining popularity, with many car enthusiasts going for the 'flush' look. Overly wide rims are used in conjunction with narrow tyres that are stretched to fit, so that the wheels are tucked nicely, close to the edge of the wheel arches. Contrary to popular believes, slightly stretched tyres can actually improve performance, as the tyres' sidewalls are stiffened to result in better performance and steering response.

An example will be Cyber Evo, a hugely successful time attack car which won the World Time Attack Challenge several times, with stretched tyres. However, overly stretched tyres not only wouldn't perform well due to the decreased contact patch, they are also potentially dangerous as there is a high chance of the tyre popping off the bead.
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6.     Too much negative camber

In order to achieve the 'flush' look, 'stance' cars might often run excessive negative camber to tuck their overly wide wheels into the bodywork of the car. While negative camber is generally beneficial to the handling of the car as it helps to fight the tyre distortion under load, excessive negative camber can result in many downsides. As camber effectively reduces the tyres' contact patch when the car isn't making a turn, excessive negative camber results in reduced braking performance, acceleration traction, affect tyre wear and increase tendency to tramline (the car's tendency to follow cracks and uneven surfaces on the road).
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7.     Backyard engineering aerodynamic theories

Aerodynamics seems simple to grasp, but is probably the most complicated topic when it comes to cars. The fact that the door-stopper shape that was popular in the 70s to 80s has been phased out, is the best prove that conventional thinking is insufficient when it comes to the complexities of aerodynamics. If anything, the ill-fated Mercedes-Benz CLR's demise at Le Mans (the low-slung and extremely wide racecar went airborne and reached a height of nearly 15m) had shown the world how wrong things can get when a car's aerodynamics is flawed.

A popular trend was to install a spacer at the mounting point of the bonnet to prop the rear of it up. It was claimed to improve the cooling performance of the engine by evacuating hot air, while some suggested that the slight tilt increases downforce. The biggest flaw with this theory is that the area at the base of the front windscreen is a high-pressure zone, which means that at speed, air will be forced into the engine bay and it prevents the radiator from dissipating heat effectively as it now takes more energy for cold air to flow in from the front of the car.
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A huge spoiler or splitter might work perfectly on a time-attack race car, but simply tacking on menacing aero parts might cause more harm than good. Many aero parts introduce considerable drag aside from downforce, which will impede straight line speed. Adding downforce to the front or the rear of the car will also determine if your car will under or oversteer at high speeds, which can be disastrous. Another recent trend that surfaced is to cut holes on the front and rear bumper of cars, hoping to increase cooling and reduce drag respectively. Cutting holes on the front bumper will introduce more drag, while the unguided, turbulent air will do nothing but impede cooling efficiency. Likewise, at speeds that are not high enough, holes in the rear bumper just gives off a cheesy look that doesn't do anything to improve your car's performance.

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