Inliners International Forums General Discussion Engines GM 4 cylinders 151 153 181

Most of those improvements were primarily for improved mileage. A typical sedan needs only about 15 RWHP to move it down the road at a steady 55 mph. When all of the less expensive alternatives to improved fuel economy were exhausted then they turn to the more costly things, like rollerized valve trains and sequential fuel injection.

My son is a bicycle racer and manager at a high end bicycle company(http://www.bikesportmichigan.com/editorials/0000087.shtml). I asked him why the big deal in the bicycle business over saving a gram of weight, especially since it costs a lot and gives miniscule benefits. His answer was that often races like Tour de France or The Tour de California or even The Paris - Roubaix are often decided by a fraction of a second. Over several days of racing up and down the sometime mountainous terrain carrying an extra gram of needless weight can mean defeat. Likewise car companies are willing to go to great lengths to advertise " best fuel economy in its class" and are more and more willing to spend more to get less in return to remain competitive.