Diesel Tuning: A Guide to Diesel Engines

A diesel engine uses heat compression to initiate the process of burning the fuel previously injected into the combustion chamber. It differs from spark-ignition engines that run off petrol gasoline, which are commonly found in standard automobiles. The diesel engine ranks as having the highest thermal efficiency of any standard internal or external combustion engines, because of its exceedingly high compression ratio. Diesel engines come equipped in two different models, including the two-stroke and four-stroke. In 1893, Rudolf Diesel built the engine as a replacement for stationary steam engines; the diesel engine became the definitive answer for commercial transportation vessels, such as locomotives, submarines, ships, trucks, heavy equipment, and manufacturing plants. Automobile manufacturers began to slowly introduce diesel engines in a few on-road and off-road vehicles, and eventually led to the rapid selling of non-commercial cars across the United States. As of 2007, nearly half of all new car sales have diesel equipped engines in Europe.

The first diesel engine prototype used injected fuel with the assistance of compressed air to atomize the fuel before forcing it into the engine through a built-in nozzle. The nozzle opening had a pin valve that was closed by a camshaft, which started the flow injection process, also known as an air-blast injection. This early model used minimal power compared to the efficiency and net power output of modern diesel engines. Today's diesel engines increase the fuel to high pressures through a series of mechanical pumps that lead to the combustion chamber by pressure sensitive injectors. Direct injected diesel engines use injectors to spray fuel through four to twelve different orifices in its nozzle. The earliest air injection diesel engines always had top notch combustion without the extreme increase in pressure during the combustible phase. Researchers have taken the effort to design efficient air injectors that will reduce the overall pollution emissions in today's automobiles.

Diesel engines employ a mechanical or electrical governor, a vital component that regulates the idling and maximum speed of the engine's fuel delivery rate. Without a governor, diesel engines exceed their speed capacity, which sets the self-destructive process in motion. All mechanical governor fuel injection systems utilize the diesel engine's gear train, which consists of a combination of springs and weights that control fuel delivery according to the automobile's load and speed specifications. Diesel engines equipped with an electronic governor utilize an electronic control module (ECM), a device that receives an engine's speed signal and other operating controls. Altering the advancement and delay of the start injection results in reduced fuel efficiency, exhaust smoke, and elevated engine noise.

There are many advantages of owning a diesel-powered engine over other internal combustion engines. For instance, diesel engines burn less fuel than petrol-based engines exerting the same force, because of the engine's high temperature combustion and expansion rate. In addition, a diesel engine lasts about twice as long as petrol-based engines due to the fuel's lubrication properties. Diesel fuel has a safer composition than petrol, and can be applied in various ways. Diesel engines generate far less heat in their cooling and exhaust processes. They accept super and turbo charging pressure without setting natural limitations, and only become restrained by the engine's internal components. Diesel engines also emit far less monoxide content than their counterparts.

Despite its advantages, diesel engine technology certainly has its pitfalls. In cold weather, high-speed diesel engines may prove difficult to ignite, because the cylinder block and cylinder head absorb the heat compression. Diesel fuel also becomes prone to waxing and gelling in cold weather. In addition, diesel engines tend to create loud noise, also known as diesel clatter, diesel knock, and diesel nailing. Diesel nailing is caused by the internal combustion process that occurs from the ignition started from the heat compression.

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“Many thanks for your fantastic service! Unit ordered Sunday, delivered Tuesday am!! Unit now fitted and, as promised, the car is transformed. Winding country lanes tackled quite happily in fifth gear. Cruising on much smaller throttle openings and immediate response on acceleration. The car behaves as a mini car should behave. I had some initial doubts about spending quite a large amount of money on this item but it is worth every penny and would not hesitate to advise anyone to do similar.”


Alan from Coventry

Suzuki Swift 1.3 DDIS 75

“I must say l'm delighted with the improvement from your chip, its on the standard settings and the difference in the car is amazing!!! I have a smile on my face every time I get in the car, and there is about 5-7mpg improvement. With the mileage l do, l can see myself getting my money back in no time at all. So if your a doubter like me, don't be because its one of the best things l've ever bought!!!”


Ian from Manchester

Audi A6 MK4 3.0 BiTDI 313

“May I congratulate you on this diesel tuning product as it has made a noticeable difference to my Land Rover Discovery. I have tried other diesel tuning boxes for my previous vehicles (Kia Sorento, Peugeot 206 and Vauxhall Vectra)... and they all produced slight engine stuttering under certain load conditions. The CHIP Express system does not show any evidence of this and is equal to the likes of an ECU remap (which I have also had done before) for smoothness and noticeable power gains. This would be the only diesel tuning product I would recommend.”


James from Callington

Land Rover Discovery (3) 2.7 TDV6 190

“A friend recommended one of your "gadgets" a year ago and being not-very-techno (but Scottish and keen to save money!) I bought one. The gizmo has TRANSFORMED the performance of my Land Rover Freelander 2 TD4 AND improved the fuel economy by a genuine 15%; so much so that I have bought another one for our Freelander 2 SD4 which is now a REAL Q-car! (And of course saves fuel...) I have never written a review before (though strangely I do read them and take notice of them, whilst half-believing that they are written by the owner's chums!) so to have made me pick up pen & paper so to speak - I MUST be delighted! Thanks for making technology so simple and so successful!”


Andrew from Lochwinnoch

Land Rover Freelander (2) SD4 190

“Be assured, this is NO gimmick. Arrived yesterday (less then 24 hours after the order was placed) and fitted today. The fitting was easy especially with the photos and instructions sent with the chip. The first thing I noticed was the responsiveness of the engine from a standing start, no more lag. I then went on a 30 minute drive both motorway and sideroads and my average fuel consumption went UP from 33.3mpg to 38.7mpg. My motorway speed varied from 60 to 85mph and the sideroads from zero to 40mph. I am so pleased with the whole result. This is worth every single penny paid. Thank you!”


Edwin from Bridgend

Ford Kuga MK2 2.0 TDCi 163

“As do many, I took the 'if it sounds too good to be true, it probably is' approach to performance chips. But CHIP Express were recommended by an impeccable source who had had experience with their product on my model of car - a Citroën C6 with the 2.7 HDi twin turbo diesel. Following a first rate response to a query, the product has delivered in spades. Ten days and more than 1000 miles of mixed town, country, low and high speed driving later I am certainly getting more than 10% more from a gallon, and probably 15%, and the performance is markedly better. Low speed response is immediate and has eradicated what I took to be baked-in lag in a big automatic turbo diesel, and mid-range acceleration is silky smooth, including up inclines. A very good car has been turned into the excellent car I had hoped for all along.”


Simon from Ketteringham

Citroen C6 2.7 HDi 204