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die 3,8er sind definitiv eigenständig, und haben, trotz 90° aufbau mit dem V8 nichts gemeinsam.

Original von Mike
....1987: 245 PS & 481 Nm (Turbo).....

Gruß
Mike

Der Sechszylinder V-Motor
Der V6 nimmt unter den V-Motoren eine Sonderstellung ein. Normalerweise ist es der Fall, daß jeweils zwei Kolben, einer für die linke, der andere für die rechte Zylinderbank, auf einem Hubzapfen sitzen. Der V6 muß die Hubzapfen teilen und versetzen, damit zwischen den Zylinderbänken keine Vibrationen erzeugt werden.
Es sind V6-Motoren mit zwei verschiedenen Bankwinkeln gebräuchlich, 60° und 90°. Beim 90°-V6 beträgt der Versatz 30°, bei 60° Bankwinkel 60° (siehe Abbildung).
Wie auch schon die Dreizylinder Motoren, vibrieren die V6 an den Enden. Daher wird auch hier wieder eine Ausgleichswelle benötigt. V6-Motoren sind hinsichtlich der Laufruhe den Reihenmotoren also deutlich unterlegen, trotz der identischen Zylinderzahl.
Warum also V-Motoren verwenden? Trotz der doppelten Anzahl von Nockenwellen, der somit höheren Reibung, dem damit einhergehenden niedrigeren Wirkungsgrad, dem 'unrunden' Lauf und den höheren Produktionskosten, hat ein V6 doch einen deutlich geringeren Platzverbrauch. Dies ermöglicht anderweitige Kostensenkungen und zusätzlich noch den einfachen Einsatz eines Frontantriebs (der weitere Kosten spart).

Original von Mike
Der 3,8´er hat NICHTS mit den V8 Motoren gemeinsam...

Original von two-lane
bei 60° V-Winkel (=Zylinderzündabstand) der "mathematisch schönste" Motor mit "fast perfektem" Masseausgleich...

Original von two-lane
-ein Kreis hat 360° :]

60 degrees:
The most efficient cylinder bank angle for a V6 is 60 degrees, minimizing size and vibration. While 60° V6 engines are not as well balanced as inline-6 and flat-6 engines, modern techniques for designing and mounting engines have largely disguised their vibrations. Unlike most other angles, 60 degree V6 engines can be made acceptably smooth without the need for balance shafts. When Lancia pioneered the 60° V6 in 1950, a 6-throw crankshaft was used to give equal firing intervals of 120°. However, more modern designs often use a 3-throw crankshaft with what are termed flying arms between the crankpins, which not only give the required 120° separation but also can be used for balancing purposes. Combined with a pair of heavy counterweights on the crankshaft ends, these can eliminate all but a modest secondary imbalance which can easily be damped out by the engine mounts.

This configuration is a good fit in cars which are too big to be powered by four-cylinder engines, but for which compactness and low cost are important. The most common 60° V6s were built by General Motors (the heavy duty commercial models, as well as a design used in many GM front wheel drive cars) and Ford European subsidiaries (Essex V6, Cologne V6 and the more recent Duratec V6). Other 60° V6 engines are the Chrysler 3.3 V6 engine, Nissan VQ engine and the Alfa Romeo V6 engine.


90-degrees:
90-degree V6 engines are also produced, usually so they can use the same production-line tooling set up to produce V8 engines (which normally have a 90-degree V angle). Although it is relatively easy to derive a 90-degree V6 from an existing V8 design by simply cutting two cylinders off the engine, this tends to make it wider and more vibration-prone than a 60-degree V6. The design was first used by Buick when it introduced its 198 CID Fireball V6 as the standard engine in the 1962 Special. Other examples include the Maserati V6 used in the Citroën SM, the PRV V6, Chevrolet's 4.3 L Vortec 4300 and Chrysler's 3.9 L (238 cu in) Magnum V6 and 3.7 L (226 cu in) PowerTech V6. The Buick V6 was notable because it introduced the concept of uneven firing, as a result of using the 90 degree V8 cylinder angle without adjusting the crankshaft design for the V6 configuration. These engines were often referred to by mechanics as "shakers," due to the tendency of the engine to bounce around at idle speed. More modern 90-degree V6 engine designs avoid these vibration problems by using crankshafts with offset split crankpins to make the firing intervals even, and often add balancing shafts to eliminate the other vibration problems. An example is the 90-degree Mercedes-Benz V6 which, although designed to be built on the same assembly lines as the V8, uses split crankpins, a counter-rotating balancing shaft, and careful acoustic design to make it as smooth and quiet as the inline-6 it replaced.