The SST pipe looks super-trick, with its various bulges and funnel shapes and its chrome-look nickel plating.
It's no secret that stock exhaust systems are usually a compromise between performance, durability, and sound levels. Manufacturers are faced with the task of meeting stringent new federal emissions and noise regulations while still trying to out-perform the competition.
Of course, many riders aren't concerned with such regulations. Often, the first thing they do when they buy a new bike is to yard their stock pipe or silencer in lieu of something that will generate more power and put out a healthier exhaust note.
That's the theory, at least. We ordered up an FMF SST Titanium pipe and silencer to put it to the test. MCUSA's own 4-Stroke Nationals rider, Devin Watson, would supply subjective data from the seat of his 2003 KTM 250SX, and dyno testing would provide the empirical evidence.
Introduced in 2001 and used by the Yamaha of Troy MX team, the $249.99 FMF SST series is the California company's top-of-the line expansion chamber.
FMF claims the key to the SST's performance is its patented shape and the use of what it calls "sonic wave technology." The 19-gauge steel SST pipe owes its name to the bulge located on the back side of the pipe that KTM calls the "SST module." The SST pipe looks super-trick, with its various bulges and funnel shapes and its chrome-look nickel plating.
Complementing the SST pipe is the Titanium 2 silencer that FMF introduced in 2002. Basically, the Ti 2 is a conversion of the company's popular Powercore 2 Shorty silencer, with the addition of a cone-shaped titanium end-cap, CNC-machined titanium stinger and titanium front cap. The canister cover is made from aluminum, but its anodized finish looks like titanium. FMF says the silencer will increase low-end throttle response and midrange power, adding that it is 60% lighter than the unit on a stock 2002 Honda CR125. FMF has dropped the Ti 2's price for 2003, although it's still a rather lofty $150, 50 bucks more than the similar but 33% heavier Power Core 2 Shorty.
FMF says the silencer will increase low-end throttle response and midrange power, adding that it is 60% lighter than the unit on a stock 2002 Honda CR125.
The FMF series gained valuable brownie points prior to installation when the MCUSA scales revealed a combined weight of 6.1 pounds, which was a significant improvement over the 7.3 pounds of the stock pipe and silencer.
Installation of the FMF pipe and silencer just might be the easiest we've ever experienced. Thanks to KTM's innovative thinking, we didn't need to remove any plastic or the seat to attach the silencer. The Austrian company put holes in the side number-plate plastic which allows for installation without removing any extraneous components. Total wrenching time is well under an hour.
Once bolted back together, Watson headed out to the track to see how the FMF pipe and silencer affected the KTM's performance. According to the recent U.S. Open qualifier, the bike felt as though the FMF pipe made a significant change.
"I wasn't sure what kind of difference this would make or if I'd notice any change at all in the performance of the bike," said Watson. "To my surprise, there was a noticeable difference in all ranges of the powerband, particularly on the top end. With the stock system, the KTM pulled hard but revved out quickly. With the FMF set-up it seemed as though I was able to rev higher and longer than with the stock set."
Our friends at
Hansen's Motorcycle put the KTM on their dyno to see if the numbers backed up Watson's claim of more mid-range and top-end power. The charts for the FMF SST pipe and SST Ti silencer indicate the FMF setup produces a boost of power in the midrange, but at the expense of some top-end steam.
The charts for the FMF SST pipe and SST Ti silencer indicate the FMF setup produces a boost of power in the midrange, but at the expense of some top-end steam.
The FMF combo cranked out more horsepower and torque from 5250 rpm all the way through 8000 rpm. It is this 3000-rpm midrange bump, right in the accessible part of the powerband that Devin enjoyed so much on the track. The FMF system comes on the pipe quicker than stock, making it feel more powerful even though peak horsepower is down to 40.9 from the stock 42.5 ponies. The FMF combo also increased peak torque slightly, and held an advantage from 5000 rpm to 8000 rpm.
This redistribution of the horsepower and torque made the powerband of the KTM 250SX feel meatier. Instead of screaming it out to ride the top-end hit, a rider can short-shift a bit to surf the rideable midrange power.
"The top end hit with the stock pipe is out of this world, but it revved out soooooooo fast," said Watson. "With the FMF, it is really snappy and faster than you could imagine."
In addition to the change in power, the exhaust note is a drastic departure from that of the stock pipe and silencer. According to Watson it is a welcome change to the factory exhaust and silencer.
"The FMF system sounds much better," says Watson. "It is crisp and audibly superior."
We were surprised that we didn't see an improvement in top-end power with the SST exhaust system, as FMF already sells its Fatty series of pipes for those looking for more mid- or bottom-end grunt. For those looking for a bigger top-end hit, you may be better served with FMF's Rev series of pipes for 125cc and smaller bikes.
In our experience, the SST pipe and Titanium 2 silencer combination is easily preferable to the stock plumbing, even if peak horsepower is down slightly. From the seat of his pants, Watson maintains he feels a marked improvement in the way the KTM makes its power.
"I personally would recommend investing a bit of your hard-earned cash," said Watson. "The FMF SST pipe and Titanium SST silencer is a worthwhile addition if you are serious about racing or just going fast in the woods."
Is
FMF exhaust system worth the $400 price tag? With a preferable, easy-to-access powerband, less weight and a much improved appearance over most stock systems, we think so.
