Have a well ported HPR zilla with the HPR 19 pipe. i currently use the stock airbox with the adapter plate and a honda 250r uni air filter. I was thinking about going to an open airbox with a big air filter. Does this make a big difference in power? I have the bored out stock carb on it. Looking for mainly top end as it has plenty down low for me. Thanks.
Off topic (sorry) but where did you get your adapter for the 250r clamp on filter?
definitely want to let the zilla breath, open filter and a pre filter will work well. i wouldnt run an open filter if you were going to be riding over water or mud however.
Shawn made them and Duncan sells just a machined plastic adaptor.
Never ran the stock box but did run a custom box with a 9" k&n with pre-filter also ran 9" k&n with pre filter no box/open air. I did notice a slight and I mean very slight drop in throttle response and top end speed with the box vs the open air filter and I had the same size filter for both applications. I also rode mine through lots of mud and water (no river crossings or anything but wet puddles) with a water proof pre filter from outerwears and had no problems with the open air box eliminator.
Since I can't seem to get the quad to hook up in the dirt it will mostly be used in the sand and I stay clear from mud and water so thats not an issue. Mainly after the horsepower. I bought the adapter plate from SBC designs on this site in the classified section.
The LT500 loves to breath. We tested with a 39 air striker & 6" K&N and then went with 41 mm & 9" K&N. We picked up over 3HP over all using Rogues Air Filter Bracket.
The LT500 loves to breath, we tested with a 39 air striker and 6" K&N and went with 41 mm and went with a 9" K&N and picked up over 3HP over all using Rouges Air Filter Bracket
Without air flow and fuel flow data. You really cant say 100% the air filter was the gain for 3hp.
With a filter switch you likely see air flow bump, and BSFC drop. If you take that BSFC with the 3hp gain and use it as a target spec. Then go back to the 6" filter and drop the BSFC (lean it) to the same spec as the 9". You will likely see that same hp gain
Bigger filter gives the ability to flow more air.
Bigger filter gives the ability to make more power.
Open filter will make more power than an air box.
I was going to ask if the smaller filter was run on the larger carb. As TOYDOC suggests could be more of a air fuel ratio thing. Also depends on the airbox.
All testing was done with A?F13-14 to 1
Unless you plan to mud ride, go without the airbox.
I also was wondering if there is a noticeable power gain with the open air filter compared to running one with the air box. Obviously jetting would have to be adjusted for each as I am sure the open filter would require richer jetting.
The LT500 loves to breath, we tested with a 39 air striker and 6" K&N and went with 41 mm and went with a 9" K&N and picked up over 3HP over all using Rouges Air Filter Bracket
I just wish the bracket could of panned out. The v2 was very nice, but the fabricator(s) just made it too expensive to sell suzukiquadracerhq
Also agree that if you go to the sand the open system will gain you some power on the top end. Good luck!
It's just my opinion, but I don't think we are making the kind of HP needed for some of BIG filters we put on.
If you crunch the numbers, sub 9000rpm, sub 90hp and a carb thats a tad over 40mm. We are over kill at 6".
To do a dyno test to really show if they like / need that size filter. You need air flow and fuel flow data. Along with two new filters, not new vs used. When you use A/F as your guide, it's after the event and a fuzzy gauge at best. With air flow you should see the gain (if it needed more area). Then your fuel flow vs power would give you BSFC. From that you go back to the 6 and verify with the same BSFC that the power was increased with the 9. That would be apples to apples.