Had done business with Jim's years ago and was very happy. However, this last trip was a disaster. First the quote of 450.00 was a lot steeper than before. But since he was local I gave him the job. Upon pickup of the vehicle a quick inspection I instantly noticed the mufflers were interfering parking brake cables. I was told this was ""normal"". It is not however, as the movement will either wear out the cables or cut a hole into the mufflers. I was then told it was my fault as I wanted ""quiet mufflers"". I am not a fan of ""cherry-bombs"". After a bit they finally fixed the problem. On to round two, once I had left the shop I notice there was now a large flat spot in the throttle from tip-in to 1/4 throttle. Looking closely to my other truck I notice that the new exhaust was much larger in size from front to rear. This does have an affect upon the operation of an engine. With high horse power and high revving engine this large exhaust is a help. But, in my case with a stock engine used in daily driving it was a determinant to driveability. I called back and got the worst customer service ever. I was told he was not going to do anything and that I was an ""idiot"". Jim then hung up on me. So why is a too large exhaust system a problem you ask. It has to with velocity of exhaust gasses in the system. The smaller the pipe the higher the velocity. This in turn with the pluses from the firing order create a vacuum effect behind the exhaust gas pulse that helps remove exhaust gasses from the cylinder. With the vacuum effect the cylinder is ready for a fresh and FULL charge of air and fuel mixture. When a too large exhaust pipe is installed the velocity is effected and reduces the vacuum effect on the cylinder. This too large of an exhaust system installed into my ride is effectually leaving exhaust gasses in the cylinder past the exhaust phase. This in end robs power and torque on the low end of the rpm scale due to a\r
NOT complete charge of and air and fuel due to spent gasses taking up the volume. It is a fine balance between too big and not enough velocity and too small and ""choking"" the engine out (getting exhaust out in a timely manner). There are many engineers who work hard at this at the factory to get the size correct. Mine was 1 and 7/8 inch internal diameter and not the 2 and 1/8 inch that Jim's installed. I would say with the attitude I got from Jim he fancies himself to be better than the trained engineers who work at the factory. Needless I can not recommend this shop to anyone, please save yourself the heartache of having to do it twice like me, go somewhere else for exhaust work.
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