CT,BIGGUN,or FMF

 

If you had gone to the site that I posted it shows dyno;s of every pipe that they tested. Some people will tell you that this pipe is better than or good, but they have no bench mark to compare to other than there stock pipe. I myself have had 4 different pipes on my 400; stock,Big Gun complete, FMF, Sparks complete, and White Brothers e-series. The big Gun was just a little better than stock, the FMF was good, with the Sparks the best with the WB just a little behind it.
The stock head pipe on the 400 is a very good head pipe after you clean out the welds. Just cleans up the inside weld will add just over 1/2 hp. The WB and the stock head pipe is just about as good if not better than many of the $500 or more complete systems.
TC Racing says to use the stock head pipe for better low end. With my set-up I can run even with a piped Raptor in a drag race.

 

Curtis Sparks or Thunderalley

 

The most you are going to get on any pipe is around a Horse and a half that is it. You should be more into how much tork you will get. Go with the Bill's or the Pro Circiut. I use to sell The Whit Bros. They do not stand behind one thing!!!! Same way with Yosh. My Distrupitors even DUMPED them. If you are going to do a exhaust do the whole thing not half. Do it right the first time and be done with it .
If you want to get the biggest bang for the buck drop a 11 to 1 piston in and rejet. That will make more power than any pipe will ever make and alot less money.

 

Guys,

From what I read several years ago (I can't remember the magazine), just about all of the systems out there really only give you about a 1-2 top end horsepower gain. It doesn't matter whether you're talking about a slip on or full pipe system. In my oppinion spending $250 - $700+ for a 1-2 horsepower top end gain really isn't worth it. I have seen that the Raptor makes tremendous gains in horsepower (up to 14 more horsepower), but it just isn't that way for the 400EX for some reason. Mind you, what I saw were dyno resuts, not "seat of the pants" tests. Sure most of these pipes flow better than stock in the mid range, and dyno results prove it. But most suffer from lack of low end power too.

About all you are going to do with the aftermarket system is to make more noise than the stock system. Unless you have a properly installed big bore kit (head mods as well as the big bore kit) and a bigger carb, a new pipe would do nothing more than make more noise. There seems to be more of a flow problem on the top end through the motor, than the exhaust system.

 

i just put the MBRP POWERTECH4 exaust on my 400EX today and man do i love it. the sound is pleasnt to the ears and it makes more power than my T4 did. its the exaust that i will recomend to any one.

it went easy and fit better than my old T4. and looks better to boot.

 

sparks is excellent dunes and track

 

i would say a sparks, they are very loud tho

 

HMF baby