In Reply to: Re: A good question merits a good answer... posted by J Turner on October 24, 1999 at 20:02:36:
You wrote: "Very few V6s are derived from V8s anymore, at least for automotive applications. The optimum angle for a V8 isn't the same as for a V6, which means when you make a V6 out of a V8, you either get a rough V6 or need to put in a balance shaft. Same thing works the other way--witness the balance-shaft equipped, V6 derived V8 in the most recent SHO Taurus."
I understand that a 90 degree V-6 is far from the optimal configuration (60 degrees between the cylinders is the optimal config). In fact, numerous V-6s are derived from V-8s. Every GM designed V-6 with the exception of the 3.0 V-6 in the Catera is derived from some V-8. Ford has numerous V-8 derived engines also, as does Chrysler.
You wrote: If I'm not mistaken, one of the primary reasons Porsche used a flat design was because it was better suited to air cooling (can mount the fan on top to blow through the cylinders, without worrying about the V). Same with VW, obviously.
Yes, that is why Porsche use the flat design. But, they also used it for the low center of gravity -- key in a sports car. Subaru still uses "boxer" 4s becuase of the low center of gravity.
You wrote: Don't blame Stuttgart or Auburn Hills--blame Kenosha. The Jeep 4.0L dates from way back in the AMC days. Although it's been reworked several times since, the 4.0L was designed as a torquey truck engine, and its architecture reflects that. Service in a $30K+ luxury vehicle was never in its original design requirements.
You're absolutely right, this engine has no place in a 30k Luxury SUV. Personally, I have no clue why Jeep has stuck with the engine. ChryCo should have ditched it a long time ago. The naturally unbalanced 2.0 L 4-cylinder in the Dodge Neon runs smoother than the 4.0 I-6 found in the Jeep.