Hemi engine
A Hemi or hemisphere engine is an internal combustion engine in which the roof of each cylinder's combustion chambers is of hemispherical form.
Hemispherical combustion chambers, which had been used for centuries in mortars and cannons, were introduced on some of the earliest automotive engines, shortly after proving the concept of internal combustion engines themselves.
Hemispherical cylinder heads have been used since at least 1901 they were used by the Belgian car maker Pipe in 1905 the Peugeot Grand Prix Car of 1912, the Alfa Romeo GP car of 1914, Daimler, and Riley. Stutz built four valve engines, conceptually anticipating modern engines. The BMW double push rod design, the Peugeot 403, the Toyota T engine and Harry Arminius Miller racing engines are a few other examples.
With the hemispherical combustion chamber design, the intake and exhaust valves are usually on opposite sides of the chamber, allowing for the combustion mixture to flow directly across the chamber, commonly referred to as "cross-flow" heads. Significant challenges in the commercialization of hemi engines revolved around the design of the valve actuation, and how to make it effective, efficient, and reliable at an acceptable cost.
Porsche has made extensive use of hemi-head engines, including the air-cooled flat-6 engine in Porsche 911 models from 1963 to 1999. The 1973 2.4 L version generated 56 hp per naturally-aspirated litre of piston displacement.
Porsche history
Professor Ferdinand Porsche founded the company called "Dr. Ing. h. c. F. Porsche GmbH" in 1931, with main offices in the centre of Stuttgart. Initially, the company offered motor vehicle development work and consulting but did not build any cars under its own name. One of the first assignments the new company received was from the German government to design a car for the people, a German: Volkswagen. This resulted in the Volkswagen Beetle, one of the most successful car designs of all time. The first Porsche, the Porsche 64, was developed in 1939 using many components from the Beetle.
During the 2nd WW Volkswagen production turned to the military version of the Volkswagen Beetle, the Kübelwagen, 52,000 produced, and Schwimmwagen, 14,000 produced. Porsche produced several designs for heavy tanks during the war, losing out to Henschel & Son in both contracts that ultimately led to the Tiger I and the Tiger II. However, not all this work was wasted, as the chassis Porsche designed for the Tiger I was used as the base for the Elefant tank destroyer. Porsche also developed the Maus super-heavy tank in the closing stages of the war, producing two prototypes.
Porsche's company logo was based on the coat of arms of Free People's State of Württemberg of former Weimar Germany, which had Stuttgart as its capital and became part of Baden-Württemberg after the political consolidation of West Germany in 1949.
Not long afterwards, on 30 January 1951, Ferdinand Porsche died from complications following a stroke.
In post-war Germany, parts were generally in short supply, so the 356 automobile used components from the Volkswagen Beetle including its internal combustion engine, transmission, and suspension. The 356, had several evolutionary stages, A, B, and C, while in production, and many Volkswagen parts were replaced by Porsche-made parts.
Porsche Awards and Reputation
In a May 2006 survey, Porsche received the title of the most prestigious automobile brand by Luxury Institute, New York; it questioned more than 500 families with a gross annual income of about $200,000 and a net worth of at least $720,000. The current Porsche model range includes sports cars from the Boxster roadster to their most famous product, the 911. The Cayman is a hard top car similar to the Boxster in a slightly higher price range. The Cayenne is Porsche's mid-size luxury SUV. The limited run Carrera GT ceased production in 2006. A high performance luxury saloon, the Panamera, was launched on Monday, 20 April 2009, and is due to be released worldwide in September and October. Recently, a spider version of the Boxster was announced, and became available after it was unveiled at the 2009 Los Angeles Auto Show.
Porsche was awarded the 2006, 2009, and 2010 J.D. Power and Associates award for the highest-ranked nameplate in its Initial Quality Study of automobile brands.
As a company, Porsche is known for weathering changing market conditions with great financial stability, while retaining most production in Germany during an age when most other German car manufacturers have moved their production to Eastern Europe or overseas. The headquarters and main factory are still in Zuffenhausen, a district in Stuttgart, but the Cayenne (and formerly the Carrera GT) is manufactured in Leipzig. Parts for the SUV are assembled also in Bratislava Slovakia. Most Boxster and Cayman production is outsourced to Valmet Automotive in Finland until 2012. The company has been highly successful in recent times, and claims to have the highest profit per unit sold of any car company in the world.
Porsche Engineering Group (PEG) has for many years offered consultancy services to various other car manufacturers. Audi, Studebaker, SEAT, Subaru, Yugo and others have consulted PEG for their cars or engines. The Lada Samara was partly developed by Porsche in 1984. PEG also helped Harley-Davidson design the Revolution 60 degree v-twin water cooled engine and gearbox that is used in their V-Rod motorcycle.
Porsche and Volkswagen
The company has always had a close relationship with the VW marque, and later, the Volkswagen Group, because the first Volkswagen Beetle was designed by Ferdinand Porsche. The two companies collaborated in 1969 to make the VW-Porsche 914 and 914-6, whereby the 914-6 had a Porsche engine, and the 914 had a Volkswagen engine, in 1976 with the Porsche 912E and the Porsche 924, which used many Audi components, and was built at Audi's Neckarsulm factory. Most Porsche 944s also were built there, although they used far fewer Volkswagen components. The Cayenne, introduced in 2002, shares its entire chassis with VW Touareg and Audi Q7, which is built at the Volkswagen Group factory in Bratislava. In late 2005, Porsche took an 18.65% stake in the Volkswagen Group, further cementing their relationship, and preventing a takeover of Volkswagen Group, which was rumoured at the time. Speculated suitors included DaimlerChrysler AG, BMW, and Renault.
On 26 March 2007, Porsche took its holding of Volkswagen AG shares to 30.9%, triggering a takeover bid under German Law. Porsche then formally announced in a press statement that it did not intend to take over Volkswagen Group, but intended the move to stop a competitor taking a large stake, or to stop hedge funds dismantling Volkswagen Group, which is Porsche's most important partner. Porsche's move comes after the European Union moved against a German Law that protected Volkswagen AG from takeovers. Under the so-called "Volkswagen Law", any shareholder with more than 20% of the voting rights has veto power over any corporate decision in the annual general meeting, any shareholder in VW AG cannot exercise more than 20% of the firm's voting rights, regardless of their level of stock holding. However, the European Court of Justice ruled against the law, potentially paving the way for a takeover.
On 16 September 2008, Porsche increased its shares by another 4.89% in effect taking control of the company, with more than 35% of the voting rights. It again triggered a takeover bid, but this time over Audi. Porsche dismissed the bid as a mere formality, since it is Porsche's intention to keep the corporate structure of the Volkswagen Group.
There has been some tension amongst the Volkswagen Group workers, who fear that a Porsche takeover might signify a hardened production efficiency control, rejection of demands for payment rises or even personnel cuts. Ferdinand Piëch and his cousin, Wolfgang Porsche, also seemed to be on a collision course.
On 13 August 2009, Volkswagen AG's Supervisory Board signed the agreement to create an "integrated automotive group" with Porsche, led by Volkswagen AG. Volkswagen will initially take a 49.9 percent stake in Porsche AG by the end of 2009, and it will also see the family shareholders selling the automobile trading business of Porsche Holding Salzburg to Volkswagen AG.
Porsche 911 GT3
The GT3 is a high performance version of the Porsche 911 sports car. It is the latest in a long line of high performance models which began with the 1973 911 RS. The GT3, named after the FIA GT class it was intended for, has a 3.8 litre naturally-aspirated six cylinder engine based on the unit used in the Porsche 962 and Porsche 911 GT1 racers.
Since its launch in 1999 a number of variations, have been added to the range. The current range (997) includes two road and three racing models. In addition, Porsche are currently developing a hybrid version which uses two electric motors and a Kinetic Energy Recovery Systems which was initially developed for Formula One.
The GT3 has had a successful racing career both in the one make national Porsche Carrera Cup series, the international Porsche Supercup and also winning numerous championship and endurance races including the GT class of the American Le Mans Series seven times, the 24 Hours of Daytona outright and the 24 Hours Nürburgring five times.
The engine of the GT3 sets it apart from most of the other 996 models although it shares the same basic 3.6 liter displacement of the standard 996 type so-called "integrated dry-sump" flat-six engine. Along with those of the GT2 and Turbo, it is actually based on the original air-cooled 911's versatile, true dry-sump crankcase, with an external oil tank. The original version of the GT3 had 360 PS (265 kW; 355 hp), compared to the 300 PS (221 kW; 296 hp) of the regular 996.