People often ask my advice on how to improve their cars for certain types of motorsport, and with my expertise in doing things for cheap/free my opinion seems to matter to them as I've gone damn fast. My speed to cost ratio is damn good, and from this I've devised my own approaches to motorsport to remain competitive. This the first in a series of performance related discussions and if your wondering, this is step 1. Begin here, as this is your base, we will continue with basics and work towards more complex concepts and ideals.
You want free performance? start shedding weight, where ever you can. Reducing weight improves acceleration, braking, cornering, fuel economy and reliability.
-Acceleration: To move an object from a stop or a slow speed to an increased speed requires energy in the form of thrust or 'push'. Your engine creates thrust through the control of explosions. Pretty simple, but it can only produce so much thrust in it's current performance level. So why not just add more power? Because the reading of power, although a way to roughly gauge the acceleration performance the engine can give, is not the total picture. If you one with a fetish for numbers, then the most important number related to your car, and something almost never talked about is: Power to Weight Ratio. Basically, the idea is simple to understand, that a 3 cylinder, 50hp Ford Festiva, can out accelerate a Cube van with a Mack truck with a full load. The Mack truck may make close to a 1000ft/lbs of torque, but obviously it has more weight to move. Reducing weight makes your engine work less hard to do the same acceleration, or from a performance stand point, allows it to accelerate faster, as it has less weight to suddenly move.
-Braking: Reducing the speed of a moving object is just as difficult as increasing it. You need to create resistance to the continuation of motion. An object wants to keep moving, once moving, thus the reason items in space just continually move in one direction endlessly, oddly enough, at rest in motion, unless something outside influences it. The more weight an object has the more difficult it is to stop, such as trying to stop a boulder rolling down a hill in relation to trying to stop a small pebble. Removing weight allows the car to stop quicker as the resistance to motion created by the brakes clamping on the discs in your GTS will be more affective.
-Cornering: The idea of an object staying in motion is true even when talking direction. Something in motion doesn't suddenly change direction without influence. However, just because you influence the object, doesn't mean it still doesn't want to try and continue it's original direction. In the case of automobiles, tires have a point of "underload" and "overload". Where there is either to little weight to retain traction with the surface of the road, underload, or when there is too much weight to retain traction with the surface of the road, overload. This is a bit of a complex subject, but basically, a car has two general points of 'float'. The majority of the car floats on the suspension, which is the deciding point on how weight transfers in relation to the drivers inputs and where the weight goes. This float is bound to create weight transfer to the wheels. Some tires will receive more weight transfered to them because the suspension allows the weight to transfer. The second point of float is in the tires, and unlike the suspension the tires do not have shocks to control the speed of weight transfer, and springs to decide the distribution of weight transfer. Tires just compress and decompress the weight delivered to them, being pinched between the road and the weight of the vehicle. This lack of control allows the weight to transfer, and deform the tires dramtically, changing the range of which the deform, pushing them closer to either underloading or overloading. Reducing the weight of your car, reduces the amount of weight transfer, keeping the tires within their under and over load limits. This allows greater speeds through corners, and more confident inputs of the driver.
-Fuel Economy: Like the description of performance, driving the car with less weight improves fuel economy, since it no longer needs to create such large powerful explosions to create enough thrust to move the vehicle. It's rather simple really.
-Reliability: Like mentioned above, reduced weight allows the engine to work less hard, reducing the wear and strain on the components. However, it also applies to all the subjects listed above, as weight adds stress and strain on all mechanical components, as well as the driver! Metals, like steel and aluminum used through out the cars construction have rates of 'flex' and rates of 'return'. The rate of return is what is most important, as it is the percentage of shape that an object retains after a certain amount of force, time and speed of bending occurs. Steel has a fairly high rate of return, but will never return 100%, spring steel has an even higher rate of return than regular steel but will also wear over time and frequency of use as well as amount of force or weight placed on it. Aluminum although more resistance to flex has a very low rate of return, it stretches on one side as it bends, and then stretches on the other side as it bends back at a very aggressive rate over that of steel and other metals. Weight speeds this process up, working with motion and momentum this creates more strain on the materials in your car, not forgetting tire wear.
What's the cost of weight reduction? Surprisingly cheap, or in many cases and applications free. In cars there is an unnatural amount of excess weight attached to the vehicle. The simple step of removing needless weight. Once the non-essentials are removed, the next step is to begin replacing items or sections of items, this too can be a near free process if your creative enough, however, the further you dive into this process the more the expense increases. Now here's the secret to this whole process. As you begin to remove weight, you will feel the process change, the initial dive into weight reduction will be quick and easy, but the further you dive in, the slower and more difficult it becomes. The idea here is to balance your options, begin removing weight, continue to do so until the cost of weight reduction begins to out grow the cost of improving performance in individual elements of the car. Reducing weight improves all elements of performance, but it will grow in complication where you can then begin to focus on the simple improvements in other areas of the vehicle. This will result in the most direct route to great, balanced performance, traveling the cheapest, and most reliable path.
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