I have the Big Gun exhaust system and I've heard the FMF power core. The fmf power core is louder than the big gun system. I wouldn't call the big gun system quite though. The sound of it kind of reminds me of a yz400 with a stock exhaust. It's fairly quite at lower rpm's but really honks as you open it up.

 

Is it a waste of money to just replace the exhaust and not the whole exhaust system? If not which one offers you the most performance gain? sound not too much of a problem just don't want neighbors to think i own a rocket.

Jera '00 400ex

 

FMF makes a good add on performance muffler for the 400. It's the FMF Powercore IV. It'll cost you a couple hundred bucks and a complete system runs almost 400 bucks. The more ya spend, the more ya get.....

Lightninn

 

Let us not forget the jetting!A good aftermarket exaust system,Without the matching jetting specs is only a 50% improvment.Let that AIR Flow!!!

 

The stock 99TRX400EX puts out 82 dB of sound in stock trim. The FMF PowerCore emits a whopping 100 dB!! That's quite a noise difference. Anyone know the rating on the Big Gun? I got these numbers from the December issue of Dirt Wheels Mag. The tests they conducted wern't very controlled, but it's something to go on.

Lightninn

 

is the process of jetting a complicated issue or is it a do-it-yourself thing. i'm really interested in doing it but only if i can do it (i don't like the labor charge at the local shop) if not a descriptive note will be very helpful!

Thanks all

Jera '00 400ex

 

It's not that hard if you read up on it.Go back 60 days, And brouse,Or read hot_sho-e's profile (posts listed),Their's tons of stuff in hear.

 

Well does anyone out there know the noise output of the Big Gun exhaust system yet or not? I'm still patiently waiting..... Thanks for all your input so far.

Lightninn

 

I don't know what all the fuss is about the Big Gun pipe. I have ridden a 400EX with a Big Gun and I have ridden mine with a White Brothers E-Series complete system, and the E-series has far more power through out the entire range. I wasn't impressed with a the Big Gun at all. Yes, it does have good midrange, but not much low end and high end improvements. The E-series isn't a quite pipe by any means, but I love its bark

 

Harlen,

Did the 400EX you rode with the Big Gun exhaust have the entire system on it or just a slip on? Does your 400EX have White Brother's entire system or just the slip on? Are there any other mods to your quad besides the pipe such as air filter or air box changes?

Lightninn