[quote author=5D4740454243555C300 link=1340281152/0#8 date=1340374882]
Dave wrote on 06/22/12 at 06:28:39: I know as far as cars go, manufacturers do not want the car to last long so you'll be buying another one. there are always better ways of gettin perfomance that the manufacturer simple will not do. the savage is purposely made to run lean to pass emissions. whos to say they use a cheap plug instead of a performance plug for the same reason.
I don't believe that manufacturers build in a "shelf life" and purposely provide a limited amount of life. When I was young cars with 100,000 miles were worn out, cylinders were badly worn and had ridges at the top where the rings didn't travel, rings were worn out, seals and guides were gone. We just sold my wife's Jetta with 264,000 miles on it and it still ran great and didn't burn any oil. The Honda it replaced had 212,000 miles on it. The cars are engineered to get good fuel mileage, meet emmisions standards, and be affordable. The design is a balance of cost vs. benefit vs. regulations......not designed obsolescence. As far as performance mods from manufacturers.....most of the performance improvements claimed by the aftermarket companies improve performance at the cost of mpg, reliability or noise.....and the claimed improvements only occur at maximum throttle as measured on a dyno. Real world improvements are generally marginal.
A cheap plug will not provide better emmision standard than a performance plug. A spark plug needs to provide a good spark - nothing more, and the standard (quality) plug can easily provide the necessary spark. Most of manufacturers use the exotic metal tipped plugs to extend the replacement interval - not to improve performance.
If you think differently.....put it to the test. Put a new standard plug in and go for a ride.....and find a hill with sign post or some landmark. Pass the landmark in high gear at a low speed that does not lug the engine and roll on the throttle and find out what your speed is as you pass another landmark.....or time yourself between 30 and 60. Then do the same with your performance plug....and see if there is any difference. The test should be repeated a few times and with the same headwinds, temperatures, etc. to be consistant.