Air box mods

[polcat]

Started to remove my air box when I notice there's not a lot of air flow, thinking of drilling some holes for more air, has anyone done this.

 

[nate007]

There's quite a few people who have modified their airboxes. I have cut out the bottom of my airbox - the "horn" that hangs down at the bottom, and that's it. Just don't cut too much out so you end up with a chance for moisture to get in. Keep your cuts to the lowest portion of the airbox, where its the most protected fom the elements by the frame.
One thing to keep in mind, is that if you increase airflow to the motor, you may need to install a fuel controller to add more fuel. Also, you may need to adjust the factory fuel settings via the control panel.

 

[**sj**]

here's a nice mod for you...easy and quiet...

get some 1" uni filters...they make them for dirtbikes...you use a 1" holesaw...I added 12 under and along the leading edge ...now I added some prefilter material to the lower hood grilles to keep the snowdust out and removed the black plate by the rectifier...

 

[bashley]

I added two 3/4" holes to the upper sides just below the lid. I then took the old "half mask" respirator I had lying around and glued the threaded cartridge holder to the hole and screwed on two Hepa filters.

I know it sounds kinda hokey, but the stock filter gets really plugged w/snow and ice sometimes, this bypasses it with adequate protection.
If the cartridges get plugged I've got an extra set in the back of the seat I can thread on quick and easy.

 

[yamadog1]

box

mike knapp has tried a few things, he says get fresh air to the stock
air box.

 

[SledFreak]

Drill holes just below your bumper and snokeling it under your airbox is the best way to keep cool air always in your motor.

 

[KnappAttack]

Don't waste your time with airbox mods. Unless the sled sits for some time heat soaking the under hood air, then the airbox cover mod will show a performance gain as it gets cool to engine quicker. If the machine is moving with airflow getting under hood, all the mods will do is make more noise and run a bit more inconsistent. Been there, done that and tested till I was blue in the face. I went back to stock airbox and machine runs much more consistent now. It all has to do with pulsations in the box ramming air/fuel back into engine @ certain frequencies @ certain RPM's. This means more to a trail rider than an additional 2 HP does at WFO only. Fuel mileage suffers with a mod box due to spit back and the loss of ramming/pulsations with the stock box also.

 

[Blue Dave]

Thanks Mike,

You just saved me a headache as I was contemplating trying an airbox mod.

Your advice has always been helpful. Thanks again for sharing your knowlege.

 

[RacerDave]

Mike, I thought you were pretty pleased with the dual K & N mod you did last season?

 

[KnappAttack]

RacerDave, I was till I took it too the trail and put a bunch of miles on. The mileage went away due to fuel spitback. Down about 2.3-3 MPG! The loss of mileage and the inconsistent running in the midrange was not worth the added 2 HP at the peak. Stock runs much more consistent now.

 

[RacerDave]

I went back and read your airbox update. It seems the more I read on this board about Apex mods, hitting the target rpm of 10,700ish rpm consistantly is really the only worthwhile effort for a hipo trail rider.