If this is at all a possible venture, I'd like to know based simply on performance, NOT what YOU are running necessarily, what the best pipe 96dbs. or less is for the 400EX. Is the FMF Q the quietest aftermarket pipe out there for this machine? Is the power boost over stock really justifiable with the Q or should I be looking elsewhere? Like I said, I'm willing to go up to about 96dbs. max, but would love to keep it lower if I can find enough power with the setup. Slip-on only.

 

If you want it quiet the stock exhuast will be best. I wouldn't waste my money.

 

honestly a pipe on a 400ex doesnt add that much power and just going with a slip-on i doubt you will notice any difference. a full pipe at best adds 3-4 hp max. i have seen many dyno sheets from magazines etc. if u buy anything i would get a full pipe kit. honestly i think the best pipe ive ever seen is the ct racing kit www.ctracing.com. around $500 average and its adjustible. anywhere from 93db to 102db. it uses a disc type silencer. by taking discs out u sacrafice a little power not really noticible but it greatly reduces the noise level. white bros e-series uses the same basic silencer but im not sure if it is adjustible. just my 2 cents.

 

I'm not looking for the same noise level as stock. I believe the factory exhaust on a 400EX is 88dbs. This is pretty quiet. I am willing to go up to around 95 dbs. for a power boost. In fact, I want a slight increase in volume. I like the 4-stroke rumble, just not when you can hear it down in the creek bottoms from miles away. And to the turtle, I know of many on here who would argue that while the EX doesn't respond as well to a pipe/jet/filter as say a Z400 or Raptor, it certainly can liven it up. I was also told by everyone I asked that unless you have significant engine mods (cam/bore/porting/etc.) to stick with the stock header because it flows enough for a factory engine. I thank you both for your replies though.......