How to make your car faster: unichip and performance exhaust Androniki Pouris tells us how to improve a car’s performance without paying a fortune. A turbocharger. Image: http://www.australianturbo.com.au/ A supercharger. Image: http://rricketts.com/wp-content/uploads/2012/02/supercharger.jpg W hen people want to buy a new car they make their choices using a number of criteria – implicitly or explicitly. How the vehicle looks, its safety (e.g. air bags), comfort (e.g. air conditioning), reliability and of course fuel economy. Similarly, some people look for cars that have turbos, superchargers, high break horse power or high kilowatts in the car. In simple terms, how fast the car can go from point A to point B, or how fast the car can pull away from a standing start. Many younger people now buy vehicles and then modify them – to make them look better or to drive faster. The challenge is that while people would like to have a fast car, they don’t really understand engines well or how their car works. Modifying a car without knowing what you are doing may cause damage rather than make the car faster – and of course you may spend more money than necessary. This article is based on my own and others' experiences of modifying a car. But before I describe my findings, just a little information on turbochargers, superchargers and other devices that everyone wants in their cars to make their cars faster. General background Superchargers and turbochargers are devices that are attached to the engine. They force air into the cylinders, so creating a pressure that is greater than the atmospheric pressure in order to increase engine output. What is a turbocharger? The turbocharger is a device which uses the exhaust gas as energy to rotate the turbine wheel at high speeds. There is a compressor wheel on the same shaft as the turbine wheel which compresses air into the cylinders when it rotates. This increases the engine output. What is a supercharger? A unichip. Image: http://www.unichip.com/Images/Products/Unichip478.jpg with DASTEK permission 22 10| 4 2014 A supercharger is a device that compresses air and so increases the density or pressure of the air that is supplied to the internal combustion engine. This gives each cycle of the engine more oxygen, letting it burn more fuel and do more work, therefore increasing power. What is a unichip? A unichip is an electronic engine enhancement product. The unichip is also called a piggy-back computer. It is connected with the vehicle’s existing engine control unit (ECU) and greatly enhances the capabilities and functions of the original computer. It essentially turns the original computer into a supercomputer. When a unichip has been installed in an engine and mapped to that engine, you can tune the vehicle in any way you wish – you can program the unichip to lower the revolutions per minute (RPM) or you can program it as an immobiliser. Another chip can be set up for high boosts if the car has a turbocharged or supercharged engine. The unichip is a plug-and-play system, so if you decide to sell your vehicle, the unichip can be removed and installed in a different vehicle. But you need to remap for each individual vehicle’s unique specifications. Although the unichip was originally designed for diesel vehicles, modifications have been made to accommodate petrol vehicles. What is an exhaust? An exhaust transports exhaust gases from the engine away from the passengers to the rear of the vehicle while conforming to noise and emission regulations. An exhaust was originally designed to let air flow from the engine to the rear of the vehicle as quietly as possible by using silencers. Silencer boxes are installed in the exhaust at strategic areas to maximise sound reduction while retaining drivability. They slow down the exhaust gases to reduce sound, and restrict the airflow out of the engine, which reduces power. A performance exhaust, on the other hand, expands airflow by increasing pipe diameter from standard size and reducing the size or number of silencers. This speeds up airflow, allowing the ❚❚❚❙❙❙❘❘❘ Everyday science A car exhaust system. Image: http://hdabob.com/wp-content/uploads/2009/11/Exhaust.jpg The author’s BMW 330ci. Image: Androniki Pouris engine to run more efficiently. The exhaust will be louder than standard, creating a sportier engine noise, which enthusiasts love. A more free-flowing exhaust gives small power gains to the engine output. Observation and experimentation The motivation for this article came from my own experience of modifying my car after a friend spent a lot of money buying a supercharger. I started searching for an alternative and possibly more cost-effective method. I found that unichip and performance exhausts can both be available and effective. DASTEK, a large Pretoria-based supplier, assisted by providing all the information on devices, as well as other examples of modified vehicles. I decided to add a unichip to my own BMW 330 ci and was pleasantly surprised by the additional power – easily felt, although the actual increase was only 5%. The figures on the right show the power increase after modifications of three DASTEK vehicles. The three graphs show the power readings at the wheels as the engine revolutions change. In the first run shown, the vehicles are standard (without any modifications), while runs two and three show the power at the wheels after the modifications, which include the unichip and performance exhausts. You can see that as the modifications are made, the power of the vehicles increases. Table 1 summarises the findings at the highest revolution points, performance without modification (standard) and with the unichip and performance exhaust. The two petrol cars (BMW and Golf) show an increase of approximately 10%. The diesel vehicle (Fortuner) shows an increase of 36.5%. It should be mentioned that the unichip was originally designed for diesel vehicles. Why do this? Many people would like to improve their car’s performance without spending a lot of money. Social media and films such as Fast and the Furious movies also contribute to the desire for speed. In my experience it is possible to significantly improve the performance of a car without spending more than R10 000 using the unichip and the performance exhaust systems. Adding superchargers or turbochargers could set you back between R60 000 and R100 000. So, for a relatively modest amount, you could improve your car’s performance by around 10% in petrol vehicles and 36% in diesel vehicles. In the future it would be interesting to find out if other external ECUs (e.g. Chipbox) provide equal or better power enhancement. Q Androniki Pouris is at the Faculty of Information and Communication Technology, Tshwane University of Technology. She likes driving fast cars! Acknowledgements The author would like to thank DASTEK for providing the relevant information as well as Mrs A Pouris, Prof A Pouris, Dr Inglesi Lotz, Mr M Piperakis and Mr P Roebuck for the valuable comments. References DASTEK, Unichip – Take control with the unichip q; accessed December 2013 at http://www.dastek.co.za/Unichip.pdf Toyota, 2013, Diagnosis Technician: Engine; Toyota South Africa Supercharging Performance Handbook, 2011, Jeff Hartman, page 182 The Turbo Hydra-matic 350 Handbook, 1987, Ron Sessions BMW M3 power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK VW Golf 1.4l power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK Toyota 3000 Fortuner 4x4 power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK Table 1: Power increase from standard to modified versions Car type Run 1 Run 3 % increase BMW M3 210.6 230.6 9.5 Golf 1.4l 61.5 67.8 10.2 Toyota Fortuner 94.7 129.3 36.5 10| 4 2014 23