I read the article and it apeals to me since I want to remain semi quiet so I can continue to putt out of the neighborhood and out to the back 40 without having to use my trailer to go around the block. The article claimed 7 dyno HP (27-34) with race core inserted, and 5HP with quiet core and spark arrestor. Stock db was 82-85, Big Gun with quiet core was 88, then 92, 98 race core. The thing is this system is mild steel ceramic coated in and out, where others are aluminum can, SS head pipes. Are there any other systems that are semi quiet with out a disc system? Is 7 HP a real # I would think the magazine would run a honest dyno test.. Stock now, my 400 has a weak top end is that the air box, or main jetting, or a complete system requirement? Thanks in advance.

 

Supposedly, the new FMF system is quieter than stock. No disc system. I've talked to FMF and they're getting the new pipes at the end of the month. They said to try back then. Hopefully it is quieter than stock and adds performance. I doubt you'll get 8 horsepower with just a pipe.

 

A friend of mine that i ride with has the complete big gun system on his 400ex, He's also running a k&n filter and no air box lid. When we drag race we are dead even and my 400 is bone stock........ The big gun system is pretty loud , it sounds like a harley with open pipes and I would say to loud to run in your neighborhood . I have the same problem trying to find a quiet silencer .I'm looking at the FMF Powercare IV squared I have also talked to fmf and the said that they will be available on 3/24. Check out the 400ex exhaust dyno charts on this site in the test bench


http://www.geocities.com/~gtthunder/gt1.html