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View Full Version : FMF 4.1 system?



Jmack
12-22-2007, 05:44 PM
Anybody know how much of hp gain with the whole FMF system? The KTM seems to be the most expensive system compared to other atv's $800! Just want to know how well it works before spending that kind of cash.

Quadevil
12-22-2007, 05:54 PM
I think +- all the exhaust kits + re jetting give around 4 or 5 hp. Correct me if i'm wrong...

pinoy525
12-22-2007, 08:43 PM
The HMF website posts printouts of their dyno runs for the 525 so you can see the power curve for both torque and hp. I wish all pipe manufactureers would do the same. Gains are around 5 hp. I don't remember if db levels were posted, but at $800 for any exhaust system, I might do a 540 kit first at $890.

pinoy525
12-23-2007, 12:56 AM
Here is the dyno chart address:
I would hope fmf gains are nearly the same.

http://hmfengineering.com/forums/showthread.php?t=3393

cheetah
12-23-2007, 12:41 PM
Most builders I've talked to says you will not really improve upon the stock header. A slip-on will gain just as much and save a whole lot of money. I would look into the HMFs. They have always made a top notch product.

Quadevil
12-23-2007, 03:02 PM
Yeah ktm stock headers are very good, you won't need to change that. Slip on is the only thing to improve.

For me it would be Akrapovic. Great design and the sound much better than hmf...

Jmack
12-23-2007, 03:24 PM
thanks for the advice. Sounds like I'll stick with a slip on.

patrickj75
12-23-2007, 08:52 PM
check out a Baldwin slip-on. they'll be out in january and i'm sure less expensive than the Akropavic which is around $700.