Do it yourself car maintenance – Exterior care and upkeep

Taking regular care of your car will ensure that your car looks showroom fresh even after it is five years old or more. Check out these useful tips to keep your car looking new and enjoy envy from neighbours and friends.

Firstly, while regular care can help in keeping the car looking brand new metallic colours are more durable than non-metallic colours over time, so choose that colour carefully.

The car should be washed every day. Always remember accumulated dirt causes more damage as it makes it harder to remove the muck and if unattended to for too long can sink into the paint of the car. The biggest enemy of car paint happens to be bird droppings which are acidic in nature and can become part of you paint job if left unattended to. In which case, the car will look like an infected Dalmatian. Always make sure that bird poop is cleaned from your car as soon as possible.

Daily Care

So, if you are thinking of hiring someone to wash your car every morning hold your horses. There are proper ways of washing a car. Merely taking a wet cloth to a car will damage the paint and result in light circular scratches on the paint and windows. Do not use just a torn shirt to wash a car, use a soft cloth to wash a car. 

Always use a high pressure water hose to wash off the dirt and muck from the car after which gently use a cloth along with running water to clean the car. Wash the car working from top to bottom. Do not forget to hose down dirt in the wheel wells, especially during summers. 

After washing the car clean, use a soft cloth to wipe off the water from the car or there will be white marks where the water dries off. Also, accumulated water can result in rust formation in panel gaps. Make sure the bonnet, boot or tailgate, and doors are opened and any water if present in the closing area is wiped dry.

Exterior upkeep

There are a variety of elements that can damage the paint on a car. Dead insects, fresh tarmac from road constructions, etc if left unattended will damage the paint on a car. To protect against all of that it is always wise to have a Teflon coating put on the car from the manufacturer. A Teflon coating protects the paint by preventing different things like marks of bird droppings, tree sap, dead insects, etc from sinking into the paint of the car. It will also prevent minor scratches on the paint while wiping the car dry.

It is also very important to polish the car at regular intervals, ideally, twice a year. Polish protects the paint by preventing marks on the paint. Also, the paint does not scratch as easily when the car has a Teflon coating and polish on it. Does not use polish over plastic bits on a car such as lights, door handles, rear view mirrors, rubber bits on door and bumpers as the case maybe. There is different plastic polish available in the market for those parts. Do not use any sort of polish on the lights and rubber strips on the windows, they are not meant to be polished, just wash the car regularly and that should be enough. Use chrome polish to polish any chrome bits on the car. Once the car is polished do not use any form of soapy car wash as it is not needed.

But all this will be null and void if there are dents and scratches on a car. Dents and scratches cause cracks in the paint which exposes the body of the car to rust and corrosion, which can prove to be an expensive affair to restore. It is always smarter to have dents and scratches touched up as soon as possible. Make sure that the touch up is done in a manufacturer’s shop. Do not go for a cheaper after market option. Manufacturer’s body shops have the exact shade of paint on your car. Also, the quality of the paint is much better than that of cheaper options, and does not fade overtime like that of the latter.

Use rubbing compound to remove fresh tarmac that gets stuck on the car from road construction as soon as possible. Be careful not to use too much of it as rubbing compound can go through polish, Teflon coating, etc and damage the paint on the car. The sooner the tarmac is cleaned off the less rubbing compound has to be used.

It’s not uncommon on highways to have stones chipped off the wheels of taller cars in front to cause scratches on the front of the car. Get these touched up as well to protect the body and paint of the car.

There might be hidden rust spots on cars older than five years or so, get them treated as soon as possible to stop them from spreading. Only get the job done at manufacturer’s body shop. Also get the chassis painted while buying the car to protect it from rust over time. Have the underbody inspected for dents and scratches in case of hitting the underbody of the car over rocks or bumps.

Make sure wiper blades are changed as soon as they slip on the windshield as they will scratch the windshield. Only use the washer to wash and wipe the windshield when the windshield is wet otherwise the wipers will scratch the windshield.

Following these tips on a regular basis will ensure that your car looks showroom fresh year after year.

Here is a quick recap of the dos and don’ts of exterior maintenance on a car.

Dos

• Wash the car regularly.
• High pressure water to hose off dirt
• Soft Cloth to clean and wipe the car
• Different types of car polish for different bits
• Teflon Coating
• Change wiper blades when necessary
• Denting and painting as and when needed
• Chassis Paint

Don’ts

• Do not use soapy water to wash the car
• Do not use wipe and wash on the windshield when it is dry
• Denting and painting in road side shops
• Do not use the wrong polish on the wrong bit
• Do not leave dents and scratches unattended for long
• Do not leave bird droppings, tarmac, etc unwashed on the car for long
• Do not leave rust spots unattended.

The Internal Combustion Engine

The modern automobile is very easy to get into and drive off. But have you ever wondered how a car works? How is it that just by turning a key a car engine starts? Ever wondered how the engine drives the wheels of the car? Read on to find out.

Everyone knows that all cars powered by fuel have engines. There are many components inside an engine which allows the engine to generate power from fuel to send rotational energy to the wheels of a car to make it move.

Let’s get to know the different components of a petrol engine.

Spark Plug – Provides the spark necessary to ignite the fuel.

Cylinder – The power generator where fuel is ignited and power is generated.

Piston – A cylindrical block of metal which moves up and down the cylinder.

Valves – Control the intake and exhaust of air from the cylinders.

Camshaft – Controls the timings of opening and closing valves.

Piston Rings – Provide a sliding seal between the piston and the cylinder necessary for lubricating the cylinder with oil. Piston rings prevent fuel/air mixture from leaking out of the cylinder.

Connecting rod – It connects the piston to the crankshaft. The connecting rod rotates at both ends so that its angle can rotate the crankshaft as the piston moves up and down.

Crankshaft – It converts the piston’s up and down movement into circular motion to drive the wheels of a car.

Oil Sump – It is located below the crankshaft and collects and circulates oil which lubricates different components in the engine to reduce friction for smooth and efficient operation of the engine.

All engines in cars operate on a four stroke (stage) engine cycle also called the Otto cycle, named after the man who invented the cycle. It is called the four stroke engine.

The Four Strokes are called;

1. Intake stroke: The piston is at the top of the cylinder, the intake valves open, the piston moves creating a suction force and sucking in air into the cylinder.
2. Compression stroke: The piston moves up to compress the air within the cylinder.
3. Combustion stroke: A tiny amount of fuel is injected into the cylinder and the spark plug emits a spark causing an explosion within the cylinder.
4. Exhaust stroke: The explosion causes the piston to move down and send kinetic energy to the crankshaft. The exhaust valve opens in the cylinder and the piston moves back up to force the combusted air/fuel mixture out of the cylinder.

Turn the key in the ignition of a car and the starter motor spins the engine a few revolutions so that the combustion process can start. It takes a powerful motor to spin a cold engine. The ignition coil connected to the 12 volt battery in a car produces a high voltage electrical spark and sends it via ignition wires to the distributer. The distributer has one wire coming in from the ignition coil and has multiple wires (the same as the number of cylinders an engine has) flowing out of it to the spark plugs of each cylinder. The ignition wires flowing out of the spark plug carry the electrical charge to fire a spark plug. The distributer allows only one plug to be fired at a point of time. If all cylinders fire at the same time there will be too much unwanted energy which will cause the engine to cease.

So the spark is sent to the appropriate cylinder according to the firing order of an engine (which is different in different engines), the camshaft which is connected by a timing belt to match the motion of the crankshaft opens the intake valve/s on the cylinder. The piston moves down sucking air into the cylinder. The camshaft closes the intake valve/s. The piston moves up to compress the air, meanwhile the oil pump pumps fuel to the fuel injector which adds the right amount of fuel into the cylinder. The spark plug fires to create an explosion within the cylinder which causes the piston to move downward and rotate the connecting rod which rotates the crankshaft. The crankshaft then sends the circular energy to drive the wheels of the car.

This four stroke cycle repeats itself as long as the engine remains on.

The cooling system for the internal combustion engine consists of a radiator and pump. The coolant in a car is circulated by the pump through passages around the cylinders and absorbs heat from the cylinders. The coolant then moves along to the radiator which cools it with air as the car moves along. The pump keeps repeating the cycle as long as the engine is running. This helps maintain an ideal temperature to ensure smooth and efficient operation of the engine. The cooling system is the same for all internal combustion engines except for on smaller engines which can be found on motorcycles, those engines are cooled by air.

Diesel engines

A diesel engine uses a four stroke cycle just like a petrol engine. All the engine components are the same as a petrol engine, except that a diesel engine does not use spark plugs to ignite the air fuel mixture. Instead it uses the heat generated in the compression stage to ignite the air fuel mixture. Because diesel is denser and heavier than petrol mere heat combined with compressed air is enough to ignite the air/fuel mixture.

Diesel engines directly inject fuel into the cylinder. The injector has to be able to withstand the temperatures inside the cylinder and still be able to spray a fine mist of fuel within the cylinder. The fuel has to be sprayed evenly all over the cylinder, before the compression stage is completed in the cylinder when combustion takes place. Before direct injection was invented in diesel engines a glow plug or heat plug (an electrically heated wire wrapped around the outside of the cylinder) was used to heat the combustion chamber from the outside to increase the air temperature within the cylinder so that the fuel/air mixture could ignite.     

Today Common Rail Direct Injection is used in diesel engines to reduce emissions and ensure smoother operation of the engine. Common Rail means same fuel line for all cylinders. It ensures that there is virtually no loss of pressure in the fuel line when fuel is injected a particular cylinder. This in turn means that there is always adequate pressure available for fuel injection. Common rail technology makes use of 2 pumps in order to bring the fuel up to high pressures. 

The first pump, an electronic pump draws the required amount of fuel. The speed of drawing fuel by the pump is determined by driver inputs and other information obtained from sensors. The second pump, which is a mechanical pump is coupled with the crankshaft and geared in order that it may rotate at half engine speed. The fuel goes to an accumulating duct (rail), where these pressures are maintained. This tank allows for the maintaining of this constant pressure even during the injection.                                                                                                                       

The whole system is monitored by the Electronic Combustion Unit (ECU).

Each fuel injector is mounted directly above the piston within the cylinder head and is connected to the fuel rail by rigid steel lines that can withstand the high pressure. This high pressure allows for a very fine spread of fuel by the injector. Like the fuel pump, the injectors are also controlled by the engine computer and can be fired in rapid succession several times during the injection cycle. With this precise control over injector firings, smaller, staggered quantities of fuel delivery can be timed over the course of the power stroke to promote complete and accurate combustion. 

The development of the modern common rail direct injection diesel engine has made diesel engines quieter, more fuel efficient, cleaner, and more powerful than the indirect mechanical injection units they have replaced. 

Rotary Engines

Also called the Wankel Rotary Engine, named after the inventor Dr. Felix Wankel works on the basic principles of a normal engine and even has the same four stroke cycle but everything else just blows your mind. Even the name of the shape of the engine spins your head. It is called epitrochoid which in short is oval like.

The different components of a rotary engine are;

1. Rotor: The rotor has three convex faces which has grooves on them (deeper the groves more the displacement of the engine) which act like a piston.
2. Housing: The oval shape of the combustion chamber is designed so that the three tips of the rotor are always in touch with the walls of the housing forming three sealed volumes of gas. Each part of the housing is dedicated to one of the four cycles of a four stroke engine cycle. There are no valves in the intake and exhaust located in the housing. \
3. Output shaft: The output shaft is located band in the middle of the engine and is connected to the centre of the piston. It spins due to the rotational energy from the rotor/piston which creates torque.

Even though a rotary engine uses the same four stroke cycle as a regular internal combustion engine the cycle is very different and amusing. Here is how it functions.

At the heart of the engine is a rotor (roughly equivalent to a piston in a piston engine). The rotor is mounted on a large circular lobe connected to the output shaft.  As the rotor orbits inside the housing, it pushes the lobe around in tight circles, turning three times for every one revolution of the rotor. As the rotor moves its edges sweep along the walls of the housing and because of the shape of the rotor and the housing the size of each chamber changes as the rotor performs revolutions.

Combustion Process

The intake process starts as one of the tips of the rotor passes the intake port drawing air into it. The size of the chamber reduces as the rotor passes the intake chamber and compresses the air in it.                                                                                                                                                 

Most rotary engines have two spark plugs because the combustion chamber is longitudinal. One spark plug may fail to spread the flame evenly throughout the chamber. When the spark plugs ignite the fuel/air mixture in the combustion chamber the explosion causes the rotor to move in the direction which will make the chamber grow in volume. As the gases continue to expand it causes the rotor to move towards the exhaust port. As the tip of the rotor passes the exhaust port the gases flow out of it due to the movement of the rotor which contracts the size of the chamber and forces the remaining gases to flow out of the chamber.

The rotor then moves along and passes the intake port and the whole process starts again.

Tyres

Tyres are a very important component of your car. They are also critical to on road and off road safety. There are different types of tyres for different terrain and road surfaces.

People are very concerned about the choice they make while buying a car. In contrast to that most people ignore the tyres. Barring a few people who are enthusiasts or have knowledge about different types of tyres, people buy and replace standard, all season, all weather tyres. However, there are different types of tyres available in the market to suit the driving needs of the driver and road conditions which the car faces. Read on to find out more.

Before we go onto different types of tyres, the difference and benefits of tubeless tyres over tube type tyres should be discussed.

Tube tyres have an inner tube between the wheel rim and the tyre. This tube holds air which supports the vehicle on its tyres. The tyre holds its shape due to the air inside the tube. Tube type tyres are vulnerable to punctures due to excessive heat generated by friction between the tube and the tyre wall, this reduces tyre life. Also, this friction increases rolling resistance and reduces fuel economy. It can also be punctured if the tyre is not fit properly.

Tube type tyres can also be punctured when a nail gets stuck in the tyre from the road. The hole made in a tube expands very quickly as the tube is made of thin rubber which is under constant friction from the tyre and this results in very quick loss of air from the tyre. This can lead to high speed blowouts, in which a sudden sharp penetration at high speed causes the tube to burst. The air expelled at high pressure from the tube forces its way out of the tyre from around the rim and the tube valve hole. The pressure exerted by this escaping air can be strong enough to rip open the tyre. A burst tyre causes a sudden loss in road contact between the car and the road which is sufficient to throw a vehicle off course violently.

Tubeless tyres have no tube inside them. The air is held between the tyre and the rim.

Most new cars come with tubeless tyres as they are safer than tube type tyres which can lose air very quickly in case of a puncture. Tubeless tyres lose air in case of a puncture only through the hole which does not expand, as a result the deflation of the tyre is gradual and takes much longer. The lack of a tube also reduces rolling resistance caused by friction between the tyre and tube. Also, The lack of a tube reduces unsprung weight and improves dynamic ability, improves handling and overall performance of the car. Tubeless tyres also increase the fuel efficiency of a car. Tubeless tyres are much safer that tube type tyres and they should be made mandatory on all cars.

Standard Tyres

Today, all major mainstream manufacturers sell their cars on standard tyres. These tyres can be tube type tyres or tubeless tyres.

Standard tyres are made up of harder compound rubber to extend the tyre’s life. This type of tyre compromises on the handling and cornering ability of the car but is not noticeable for a majority of drivers. This is an average type of tyre which can be used in all seasons such as dry, wet, cold or hot. And they work equally well in all conditions. The tread on these tyres are designed to have maximum grip while reducing road noise and enables adequate dispersion of water through its grooves on rainy roads. These tyres offer the perfect compromise between handling and cornering ability of a car and ride comfort, low road noise and safety.

Performance / Summer tyres

Performance or summer tyres are made up of soft compound rubber. They are designed to give maximum grip at high speeds during dry weather conditions. Most sports cars are fit with performance tyres to improve their handling and cornering ability. These tyres are also available from the aftermarket for drivers who want increased handling and performance from their tyres.

However, the soft compound on these tyres means that the tyres wear out faster. Also because the groves on these tyres are less it does not work very well in the rain as the dispersion of water from under the tyres is less. They can be used through the year if its warm all year round in that region and there is little rain. The driver should be very careful in checking the wear on the tyre because if the tyre is worn out there will be little or no grip on wet roads. The extreme example of these tyres are used in motor sport and are called ‘slicks’ as they have very little tread on the contact patch of the tyres.

Snow / Winter tyres

These tyres have a larger contact patch and have larger and more pronounced tread patterns than standard tyres, so that there is maximum grip on snow and on loose mud. True snow tyres come with tiny metal studs in the tread for increased grip on loose or fresh snow. These tyres cannot be used on normal road surfaces as they will wear out very quickly and damage the road surface. There is more road noise from the tyres. These tyres are crucial for driving on snow and provide maximum grip while accelerating, cornering and braking on snow.

Off-road tyres / All terrain tyres

These types of tyres are often used on vehicles like SUVs that go off road frequently. The rubber is neither soft compound nor hard compound but is somewhere in between. These tyres have big chunky tread so that it can provide good grip on loose surfaces such as sand and mud. The side walls on these tyres are stiff so that the tyre can cope with uneven surfaces and potholes. These tyres are very noisy when driven on normal road surfaces due to the big gaps in the tread of the tyres. They wear out very quickly on normal roads because there is too much grip from the tyre on the tarmac. It will also effect fuel economy for the worse due to the extra friction between the tyre and the road.

Run flat tyres

Run flat tyres are designed to minimize loss of handling of a car after a puncture has occurred. It allows the car to be driven on the punctured tyre so that the driver does not have to change the tyre. However, after a puncture has occurred it can be driven only for a short distance and under a limited speed. Run flat tyres offer a very bumpy ride and cause the car to feel even minor jerks and bumps on the road as there is less air in the tyre and the sidewalls are very rigid to maintain the shape of the tyre in the event of a puncture.

The run flat tyre was originally developed for important people and heads of state. The objective was to keep their cars going even if the tyres were shot and hit by bullets. Today, manufacturers offer run flat tyres so that they can save space reduce the unsprung weight of a car by not offering a spare tyre in the car.

Upsizing tyres

Looking to upsize the tyres and wheels on your car? There is reason and logic behind upsizing the wheels and tyres of a car. Be careful of getting the wrong upgrade. Read on to find out more.

Upsizing the size of a tyre is increasingly becoming an obsession with people to create a visual appeal on their car. Don’t be fooled however as shops in the aftermarket might fit your car with big wheels and tyres to make the maximum amount of money from the customer.

There is method behind the madness of upsizing tyres and wheels. Manufacturers offer a standard size of tyre and wheel rim on a car for a reason. They do so to give the car the best of both worlds of increasing performance dynamics of a car, increase fuel efficiency of the car offer a more comfortable ride and decrease road noise. They choose the best compromise.

Manufacturers do leave room in the wheel well for a calculated upsizing of tyres and wheels on their cars. This is done so that owners can upsize the tyre and wheel size to increase performance and or increase traction on different road conditions.

The ideal maximum calculated upgrade that can be done without upsetting the cars driving dynamics is 3% of the original size of the wheel rim.

Any upgrade above this will result in a noticeable drop in fuel efficiency and compromise on ride and handling of the car. Too big an upgrade in wheel and tyre size will also increase the weight of the car giving the driver no real benefit from the upgrade.

It is advisable to go for an upgrade anywhere between the 3% margin for better performance and handling, increased grip and creating a visual appeal.

Do take note that upsizing the wheels and tyres will decrease the fuel efficiency of the car and will result in speedometer error on the car.

Checks to be performed after fitting bigger wheels and tyres on a car

Also after the new wheels are fit onto the car, turn the steering from lock to lock positions in both left and right directions to make sure that the wheels turn till the steering wheel can turn no more. Ensure that the wheels do not touch the inside of the wheel well as this will damage both the tyres and the suspension and will adversely effect the handling of the car.

Another check that has to be performed after upsizing is to check that there is enough gap between the tyre and the wheel well to absorb bumps and potholes on the road. Take the car for a drive on an uneven or broken road to test that the bigger wheels and tyres are compromising on the ride quality. Also roll down the windows and drive and make sure that there is no noise and feel of the tyres coming in contact with the wheel wells.  

Super Charger

A super charger was developed for speed freaks who wanted to make their cars go faster. It works on the principle of forced induction system. It’s one and only purpose is to make a car go faster.

Ever since the invention of the automobile, enthusiasts, engineers and speed junkies have been trying to make the car go faster and faster. A car can be made to go faster by a bigger or more powerful engine. But this costs more also it is more heavy which reduces the power to weight ratio of a car. The other way of increasing the power output of an engine is by adding a supercharger to a normal engine to boost power.

Supercharging is a method of forcing more air into the combustion chamber which has come to be known as forced induction system. A supercharger is powered mechanically by a belt or chain drive from the engine’s crankshaft. In essence what the supercharger does is suck more air into the cylinder which is combined with more fuel supply leading to a bigger explosion which results in higher power output and torque which makes a car go faster. On an average supercharging adds 46% more horsepower and 31% more torque. At sea level a typical boost from a supercharger places about 50% more air into the engine.

The trouble is, as the air gets compressed it gets hotter which means it loses its density and cannot expand during explosion. This means that it does not produce as much power under explosion. AS a result an intercooler is used to cool the compressed air before it goes into the intake manifold. It works like a radiator where cool air or water is passed through a system of pipes. When the hot air encounters the cooler pipes it cools down. This increases the density of the air which creates a denser charge upon entering the combustion chamber.

There are three types of super chargers: Roots super charger, Twin-screw super charger and Centrifugal super charger. Each uses a different way to move air to the intake manifold of the engine.

The Roots supercharger is the oldest design. It uses meshing lobes to spin air from the fill side to between the lobes and then to the discharge side which leads to the intake manifold of the engine. Large quantities of air move into the intake manifold and stack up to create pressure. Roots superchargers are large and sit on top of the engine. They are usually used in muscle cars and hot rods. They are the least efficient type of supercharger as they add a lot of weight to the car and provide busts of air instead of a smooth and continuous flow.

A twin screw supercharger works by pulling in air through a set of meshing lobes that resemble the groves on a screw. A twin screw supercharger compresses the air inside a rotor housing. The air pockets decrease in size as they move from fill side to discharge side which leads to the intake manifold of the engine.  As the air pockets shrink, the air is squeezed into a smaller space. This makes twin-screw superchargers more efficient, but they cost more because the screw-type rotors require more precision in the manufacturing process. Most twin-screw superchargers sit on top of the engine.

A centrifugal supercharger powers an turbine which draws in air at very high speeds into a small compressor housing which then sends it outwards towards the intake manifold.  Air leaves the impeller at high speed, but low pressure. A diffuser (a set of stationary vanes that surround the impeller) converts the high-speed, low-pressure air to low-speed, high-pressure air. The air slows down when it hits the vanes which reduces the velocity of the airflow and increases pressure. Centrifugal superchargers are the most efficient type of supercharger. They are small, lightweight and attach to the front of the engine instead of the top.

Superchargers do not suffer from lag as it is powered by the engine. On the downside, because superchargers use power from the engine they decrease its efficiency. Roots and twin-screw superchargers provide more power at lower RPM while Centrifugal superchargers provide more power at higher RPM.

Turbo Charger

A turbo charger is a forced induction system which can be used in a naturally aspirated engine. There can be two reasons for turbo charging an engine, one is to increase the power output of an engine and the other to increase the efficiency of an engine.

A turbo charger has a turbine and compressor on a common shaft. The turbine which is placed in the exhaust manifold starts to rotate as exhaust gases from the engine start flowing out. The kinetic energy generated from the rotating turbine drives the compressor. The compressor sucks in air from outside and pumps it into the intake manifold, as a result there is more air entering the cylinders. There is a wastegate which is controlled by the Electronic Combustion Unit (ECU) that vents excess exhaust gases to bypass the exhaust turbine so that too much air is not pumped into the cylinders which avoids physical damage to the engine.

When there is more air entering the cylinders more fuel can be added to produce a bigger explosion which results in more power and torque output from the engine. This is a huge advantage over using a bigger engine to produce more power. Using a bigger engine leads to more weight and lower efficiency, also it decreases the power to weight ratio of a car. By using a turbo charger the weight of the car does not increase by much but the power output significantly increases, thereby increasing the performance of the car.

A turbo charger may also be used to increase the efficiency of an engine without any attempt to increase the power output of the engine. The compressor pumps in a limited amount of air into the cylinders which helps to ensure that all fuel is burnt before being vented at the start of the exhaust stage.  However, a turbo charger is not completely efficient. One cause of inefficiency is because of a turbine being present in the exhaust manifold which restricts the exhaust. This means that on the exhaust stroke the engine has to use more push harder against backpressure. This results in a loss of pressure from the cylinders which are firing at the same time.

When a turbo charger is used to increase performance the main problem is that the boost in power is not immediate as it takes time for the turbine to speed up before the boost is produced. This results in lag as the car moves ahead and then lunges forward when the turbo kicks in, this is called turbo lag.

To overcome this problem two turbo chargers can be installed onto one engine. The smaller turbo charger will provide boost quickly at lower engine speed to reduce turbo lag, but will be cut off by the waste gate at higher engine speeds. This is when the bigger turbo chargers takes over to provide more boost at higher engine speeds.

Variable Geometry Turbo Charger

A Variable Geometry Turbocharger is capable of altering the direction of exhaust flow to optimize turbine response. It has movable vanes in the turbine housing to guide exhaust flow towards the turbine. An actuator can adjust the angle of these vanes, in turn vary the angle of exhaust flow.

At low RPM the vanes are partially closed hence accelerating the exhaust gas towards the turbine. Moreover, the exhaust flow hits the turbine blades at a right angle which makes the turbine spin faster.

AT high RPM the exhaust flow is strong enough. The vanes are fully opened to take advantage of the high exhaust flow. The vanes can also direct excess exhaust pressure out of the turbo charger as a result there is no need for a wastegate.

Benefits of turbo charging:

1. Increased power from an engine of the same size or reducing the size of an engine with the same power output.
2. Increasing the power to weight ratio of a car.
3. Increasing the fuel efficiency of an engine.

Earlier turbo charging was done purely for performance purposes. After people have realised the benefits of turbo charging, the trend is increasingly going towards turbo charging to increase efficiency and reduce emissions.

The purpose for which turbo charging was established has started growing at a faster rate recently. The current BMW M5 has switched to a turbo charged V8 engine downsizing from the naturally aspirated V10 in the previous model and yet it produces more power than the outgoing model. 

Variable Valve Timing (VVT)

In the current automobile scenario where there seems to no end at looking for technology that reduces fuel consumption and increases performance of car engines VVT has turned out to be one the most popular systems.

An internal combustion engine uses valves for intake and exhaust. These valves are either directly or indirectly driven by cams on a camshaft. The cams open the valves for a certain amount of time during each intake and exhaust cycle takes place. By principle this operation is fine and should operate without any compromise to combustion of fuel and efficiency. However, at high engine speeds the engine requires large amounts of air. 

The time for each intake cycle of the valves becomes inadequate as more air is required to burn more fuel to produce enough power to maintain the current speed or increase the speed of the vehicle.

This is where Variable Valve Timing comes into play. VVT is a piston engine technology that deliberately delivers inconsistent timing of the intake and / or exhaust valves. The benefit of this is fuel efficiency and the ability to deliver peak performance over a variety of driving conditions. Just like normal engines. The main advantage of VVT is that it can prolong exhaust and intake cycles at high speeds and reduce cycles at slow speeds. This results in good performance of the engine at high speeds and increased fuel efficiency at low speeds.

Pressure from environmental bodies to increase fuel efficiency standards has forced all mainstream car manufacturers to adopt some form of Variable Valve Timing or the other. Most mainstream manufacturers use proprietary technology for VVT systems and have affixed a proprietary term to distinguish their engines from other manufacturers.

Some of those terms are as follows:

• Alfa Romeo - Twinspark technology
• Audi - VVT
• BMW - Valvetronic, VANOS and Double VANOS
• Ford - Variable Cam Timing
• GM - Double Continuous Variable Cam Phasing (DCVCP), Alloytec and Variable Valve Timing (VVT)
• Honda - VTEC, iVTEC and VTEC-E
• Hyundai – MPI, CVVT, VTVT
• Lexus - VVT-iE
• Mazda - S-VT
• Mitsubishi - MIVEC
• Nissan - N-VCT, VVL , CVTC and VVEL
• Porsche - VarioCam and VarioCam Plus
• Subaru - AVCS and AVLS • Toyota - VVT, VVT-i and VVTL-i
• Tata - Variable Turbine Technology (VTT)
• Volkswagen - VVT
• Volvo - CVVT

Manual Transmission

Changing gears may be tiring in traffic but it is necessary to keep the car’s engine at the right speed compared to the road speed of the vehicle.

Ever wondered why it is that the driver has to depress the clutch pedal and change gears while driving a car? It is necessary for regulating torque transfer from the internal combustion engine. Cars need a transmission due to the physics of the internal combustion engine.

All engines have a maximum RPM value or a redline beyond which the engine cannot perform revolutions. Every engine has a RPM band in every gear which generates maximum horsepower and torque. The driver shifts gear to stay below the redline and near the RPM band of its best performance.

The Clutch engages and disengages the drive shaft from the gear box allowing the driver to select the appropriate gear judging by the road speed at which the car is to be driven at. In a typical 5 speed gear box the clutch disengages and engages different gears to the output shaft which is connected to the differential which drives the wheels of the car. When the car is to be moved from stationary position the gearbox is moved from 1^st to 5^th as the car picks up speed.

There is always more torque at lower gears as compared to higher gears. Always use lower gears while driving up a hill surface. Also, use lower gears while driving down a hill when the road surface is slippery or loose, this ensures that the car does not exceed a certain speed which the gear cannot go to thereby keeping the speed of the vehicle slow. Second gear is the ideal gear for such situations. Higher gears have less torque compared to lower gears but allow higher road speeds.

Selecting a higher gear and driving at low RPM increases the fuel efficiency of a car, but if the speed is too low for the gear the driver can hear a clattering noise which means a lower gear needs to be engaged as the speed is too low for the current gear to carry and can damage the mechanical components of the car.

Although modern cars come with rev limiters which do not allow the driver to exceed a certain RPM or engine speed, it is not recommended to touch maximum RPM too frequently as it can damage the engine.

Cars have only one reverse gear because there is no need to drive fast while going backwards, it is only used to manoeuvre the car. That is what would happen if a car had only one forward gear.

Multi-link Suspension

A multilink suspension set up not only helps in bettering the handling of a car but also improves ride comfort.

A 5 link suspension setup also known as multi-link suspension uses multiple linkages to control forces from different angles reacting on wheels. It is a setup for the rear suspension of cars (i.e. the wheels not connected to the steering). These linkages deal with side to side, up and down, and in and out forces acting on the cars wheels.

The benefit of 5-link suspension is that it offers a good blend of handling and ride comfort. The suspension can absorb bumps more easily due to its ability to absorb bumps from different directions and also deal with high speed manoeuvres. 5-link suspension is also good for off-road vehicles due to its ability to cope with forces acting from different angles on the wheel.

The four links that connect from suspension to body are independent from the others. As a result while going over a bump with one wheel, the wheel which is going over the bump deals with the vertical movement while the other wheel is completely unaffected. Also, it allows the axle to move and rotate freely without having to cope with the suspension movements from the wheels.

The fifth link which connects the axle to the body of the car prevents the axle from sliding horizontally. While cornering at high speeds it prevents the axle from swaying from side to side thereby upsetting the weight distribution of the car. 

Electronic Stability Program (ESP)

The Electronic Stability Program (ESP) controls brake and acceleration to each wheel so that each wheel has maximum traction at all times.

We often hear or see high performance cars understeering or oversteering, but if the roads are slippery or you push the car to its limits while driving, any car can oversteer or understeer.

Understeer happens when you go around a corner much too fast and the front wheels don’t have enough traction. As a result you end up going forward instead of turning. Oversteer is just the opposite, the car turns more than the driver intended to causing the rear wheels to slide and the car to spin. Understeer is common on front wheel drive cars while oversteer is common on rear wheel drive cars.

Electronic Stability Program helps to control these movements before they become accidents. ESP cannot work on its own, it uses the car’s other safety features like Anti-lock brakes (ABS) and Traction Control plus a few sensors to keep the car on the road.

The Electronic Stability Program uses Traction Control to cut acceleration from the wheels the moment it detects wheel slippage thereby preventing oversteer and understeer. ESP also uses ABS to activate the brakes on individual wheels at the required level to prevent the driver from losing control.

Electronic Stability Program functions via three types of sensors:

·         Wheel-speed Sensors – Measures the speed of a wheel in relation to the engine speed.

·         Steering-angle Sensors – A sensor in the steering column analyses the steering input angle by the driver and the direction the vehicle is travelling in. It makes corrections by changing the speed of the vehicle so that the driver can have constant control of the car.

·         Yaw Sensor – A sensor located in the centre of the car detects side to side motion of the car. This helps the computer know which wheels have more grip and transfer more or less power or brake pressure (depending on the situation) to a wheel to have maximum traction at all times.