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FCI vs. SX Intake

8911 Views 28 Replies 17 Participants Last post by  spudnik
Hello, I have a 2009 450xc. I eventually want to upgrade the intake on it. I was wondering which intake is best for the money, the FCI or the SX intake with the 2010 hardening rubber piece. I don't want to spend $300 for an intake when I could get the same results with one that's roughly $200 cheaper. Any input would be great. Thank You.
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basically FCI, has the worst filter in the world for offroad

SX just as good and uses the best type of filter
Have either of you guys actually run the FCI ? I have over 500 engines hours on multiple FCI's, 350 hrs plus on YFZ's and around 150 on ktms all racing at a national level (MX) and have yet to see anything get through these when properly maintained.

two things here, the S&B filter is an 8 ply unit, double that of the average crappy k&N (which are typically only 3 or 4 ply). Most guys under oil these filters, SOAK em allow to drain for 24 hrs or longer before fitting. two, the outerwear is critical, this skins off all the fine dust into the bottom of the airbox keeping the filter clean, KTM even offers this type of outerwear technology (via twinair) for the stock foam filters. I can do a full natioanls weekend of MX without a filter change ( 5 to 7 races) but I do change the outer wear every 2 to 3 races depending on the conditions. I have run grease on the inside of the intake boot and have yet to find any evidence of dust getting through. Top end life on the SXF has been superb.

In comparsion I have had several stock KTM filters come off from major heavy jump landings on the MX track and ruined at least one KTM top end as a result of sucking dust for a whole moto thereafter........... and have had issues with heavily clogged filters killing power and trying to pull off the frame. I used to grease the hell out of the stockers trying to keep them in stuck into place and was changing them every moto clogged to hell...........

I would concede that for GNCC mud and water slush the stock filter setup is way better protected due to the physicall layout. And dust clogging is less of an issue when conditions are wet. In this regard the stock layout is very good

the twin airbillet filter frame goes allong way to address the crappy plastic filter frame "issue" (deforms way to easily) but is hellishly expensive, and the Sx trunk insert goes along way to sorting the intake trunk deflection issue.......... The SX trunk / stiffener / twin air Alloy frame is a good setup overall, cost is the same or more than an FCI.

Personally i have had a great run out of mutiple FCI setups for MX use under a wide variety of conditions including pretty damn muddy and wet and chokingly bad dust. The outerwear is a critical part of the equation and they do wear out from pulsing against the filter ridges.

Down this way allot of speedway car guys run S&B filters due to there superior filtration compared to K&N's.
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IMO why change something that already has a really good design...
HP and throttle response. FCI provides both. and is a better setup for matching up to a larger 43.5mm carb setup and carb end velocity ring due to teh larger overall diameter at the carb junction.

My KTM pretty well hole shots the field every time........
Same results for cheaper? NO it can't be done.The FCI has better throttle response and power gains.THe difference is very noticeable.It's easier to clean and oil and won't pop off coming off of big jumps.The key is keeping it clean and oiled and with the outerwear it does not clog up as quick as the oem foam filter.The oem sx setup is very good but requires more work keeping it clean and oiled.
Either way you go, you won't notice a difference unless your carb is properly jetted.
Ive been running the FCI for half a year on both of my sx's. It improves throttle response over the sx intake with the stiffener. I havent noticed any dust getting through the filter, the intake trunk is always spotless inside.
FCI is way better than the sx intake. FCI, Fastranchero carb mods, dasa or bill's pipe = lots of holeshots on other built bikes.
This is almost like whichtire or pipe is better. They both seem to work well. For us we went back to the SX filter. But in thedesert, soetimes we will do quick filter changes and the stock setup seems to bebetter for that.
It has been a while since I installed the FCI intake on my 525XC but I remember thinking "Wow, what a difference!" I don't think the stock SX intake works on the XC so that is not even an option. I think the seat pans are different and the SX intake interfers with the supports on the XC pan.
here is what I know you throw away $300.00 no gain on the dyno lost power with the FCI Lets in fine dirt SX will work on a XC must cut the seat pan on 2008 seats 2009 XC seat has the same pan as the SX
here is what I know you throw away $300.00 no gain on the dyno lost power with the FCI Lets in fine dirt SX will work on a XC must cut the seat pan on 2008 seats 2009 XC seat has the same pan as the SX
Finally somebody agrees with me!
Is there a certain oil you guys are putting on the filters?
i use the K&N oil, lots of it...... let it drain out standing.

Bill: not doubting you, but heck I can feel the difference between the two systems on my engine, especially on the top end / over rev phase the FCI pulls allot harder where as the SX intake the engine seems to choke off ??? I didn't have the insert, this was back before that came out.

you guys haven't had issues with the stock filters dislodging from the filter mounting frames on killer jumps ?? I have had that happen three times......

hmmm back to the dyno in the next few months I think ? all three machines for a day of dial up.........
I have no experience of the fci, but never had an issue with the stock filter. Have had many hard landings bending and breaking axles but never had the filter pop off. With both bikes I have taken the metal holder and put a more severe bend in them to put more pressure on the filter. I soak filters and wring them out then put the thickest bearing grease we have on the farm round the rim.
yeah, done the HD grease deal........ popped clean off each time.......

if there is a better mouse trap I'm all ears ! Don't miss changing filters every race though.......
The FCI let fine dirt through and it was soaked in oil. Bill can vouch for this as he rebuilt my motor. I did notice better snap from the fci but no improvement in the mid to top power. I love S&B filters, my duramax and yukon both have S&B intake or filter on them. No dirt gets through those. I went with a twin air aluminum 5 pin frame and twin air foam. Intake is now spotless and has never popped off. I use the stock intake tube and put 2 hose clamps around it like a lot of people have on here and that fixed the collapsing issue. Kiwi, thats probably why your intake felt like it was choking on top end.
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