The SDI engine is a design of

naturally aspirated A naturally aspirated engine, also known as a normally aspirated engine, and abbreviated to N/A or NA, is an internal combustion engine in which air intake depends solely on atmospheric pressure and does not have forced induction through a turboc ...

(NA) direct injection

diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

developed and produced by

Volkswagen Group Volkswagen AG (), known internationally as the Volkswagen Group, is a German public multinational conglomerate manufacturer of passenger and commercial vehicles, motorcycles, engines and turbomachinery. Headquartered in Wolfsburg, Lower Saxon ...

for use in cars and vans, along with marine engine ( Volkswagen Marine) and Volkswagen Industrial Motor applications. The SDI brand name (derived from "Suction Diesel Injection" or "Suction Diesel Direct Injection", the latter a literal translation of the ) was adopted in order to differentiate between earlier and less efficient indirect injection engines, called SD or "Suction Diesel", which were also produced by Volkswagen Group. SDI engines are only produced in inline or straight

engine configuration The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engines are often categoriz ...

s; and as they originate from a German manufacture, are designated as either R4 or R5, taken from the . They are available in various displacements (from 1.7 to 2.5 litres), in inline-four (R4 or I4) and inline-five (R5 or I5), in various states of tune, depending on intended application. The SDI engine is generally utilised in applications where reliability and fuel economy are of primary concern. These engines lack any type of

forced induction In an internal combustion engine, forced induction is where turbocharging or supercharging is used to increase the density of the intake air. Engines without forced induction are classified as naturally aspirated. Operating principle Ove ...

, hence the use of 'suction' in the title, and their power output is lower than a

turbocharged In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the ...

engine of similar displacement. For example, the 2.0 SDI engine fitted to the Volkswagen Golf Mk5 has a peak power output of ; whereas the same engine in

Turbocharged Direct Injection TDI (Turbocharged Direct Injection) is Volkswagen Group's term for its current common rail Fuel injection#Direct injection systems, direct injection turbodiesel engine range that have an intercooler in addition to the turbo compressor. TDI engi ...

(TDI) form is rated at or , depending on specifications.

SDI engines and applications

:Notes: Volkswagen Marine engines were originally rated according to Directive 80/1269/

EEC The European Economic Community (EEC) was a regional organisation created by the Treaty of Rome of 1957,Today the largely rewritten treaty continues in force as the ''Treaty on the functioning of the European Union'', as renamed by the Lisbo ...

. However, some are now being rated to ISO 8178-4.

Lubricants

Like their related Volkswagen Group

diesel engines, Volkswagen AG requires that motor oil lubricants for SDI engines must conform to one of the officially approved standards VW505.00, 505.01, 506.00, 506.01, or 507.00. 'Generic' oil standards such as the

American Petroleum Institute The American Petroleum Institute (API) is the largest U.S. trade association for the oil and natural gas industry. It claims to represent nearly 600 corporations involved in extraction of petroleum, production, oil refinery, refinement, pipeline ...

'API', or European Automobile Manufacturers Association 'ACEA' are not in themselves recognised or approved by VW, although such an oil may also conform to one of the specific VW standards. Many formulations of motor oils from most brands are now "VW Approved" to the above standards. However some unapproved 'off brands' print the VW number on the label, implying that they meet the said standard, but hide in small type the word "recommended". Only Volkswagen AG can grant the necessary approvals, following in-house testing. Volkswagen Germany (and Volkswagen of America) publish up-to-date lists of currently approved oils on their respective websites, along with the technical resource, erWin. All SDI-engined models with "LongLife Servicing", "Extended Service Intervals", "ESI", or "WIV", must be lubricated by official 'LongLife' lubricants, namely VW506.00 (for non-PD), VW506.01 (for PD), or VW507.00. According to VW 'generic' longlife lubricants, or those certified by other manufacturers such as

General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...

BMW Bayerische Motoren Werke AG, trading as BMW Group (commonly abbreviated to BMW (), sometimes anglicised as Bavarian Motor Works), is a German multinational manufacturer of vehicles and motorcycles headquartered in Munich, Bavaria, Germany. Th ...

Mercedes-Benz Mercedes-Benz (), commonly referred to simply as Mercedes and occasionally as Benz, is a German automotive brand that was founded in 1926. Mercedes-Benz AG (a subsidiary of the Mercedes-Benz Group, established in 2019) is based in Stuttgart, ...

should not be used.

SDI vs other VW Group diesel engines

The following table contains a selection of current and historical

compression-ignition SDI

diesel engines The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the die ...

for comparison of performance and operating characteristics with other naturally aspirated and forced induction engines of the same capacity:

References

External links

VolkswagenAG.com
– Volkswagen Group corporate website

{{Volkswagen Group brands Volkswagen Group diesel engines Diesel engines by model Diesel engine technology Straight-four engines Fuel injection systems Marine diesel engines