You are correct in what you say, however the question asked was if a slip on is as good as a complete exhaust.Now I do not know if TK used a flow bench or not but I assume they did, and know they showed gains over stock on the dyno. No one else has done this except for the eastside exhaust. Any body can put together a larger pipe and free flow muffler and then call it a performance system The difference between the eastside and MRP from personal experience is pretty noticeable. Now for the 250cc you have the Hammerhead and the MRP which are basically the same. Size of pipe and length and mufflers look almost identicle internally. I ran the MRP on my 250cc and could not get rid of the flat spot on rapid acelleration. I just let everyone convince me it was the cv
carb and that I needed either a pumper or a slide carb. I put the TK on to try and the flat spot went away but the biggest difference was at about 3/4 throttle the motor come alive.Now will it perform this way with a stroke?? Now the average person will be perfectly content with a slip on since they will tell a difference in performance over the highly restricted stock muffler, but their are those who want more performance. The sad part of it is the chinese parts market is ripe with the word performance but with nothing to back it up.Now when I started messing with my heads on these buggies I asked a lot of questions and one person in general who designs cams told me that he had an uncle who worked years ago for the Ford racing team and from the books he told me to read and the story's from his uncle the flow bench is something some totally relied on but that a good builder will use it only for a reference point since there is such a thing as too much flow and the only way to check the end result is on the dyno. You are also correct when you talk about the complexity of volumetric efficiency for it is a science that most know very little. I know some from reading and consulting with people but it sometimes does not take someone with knowlege long to loose me, and I am not an expert on the subject but just a novice. Now I believe the question xlint89 origionally asked was if anyone can tell what difference the exhausts make over a fmf on a stock pipe and if anyone has ever dynoed the exhaust vs stock exhaust. I give him my answer based on what I had personally experienced and know with the East Side, MRP,FMF,Hammerhead and TK exhaust. I respect your knowlege and wouldn't mind meeting and or brainstorming some day. By the way where the H*ll is Penciltucky LOL
TOM
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