I was reading a recent article in American Rider magazine by Joe Minton discussing air cleaners. I may be mis-stating the article but I believe he was saying the stock AC out performed the high flow AC's in the lower rpm band. At least on a stock engines. And across the entire rpm band there was no real difference. Seems like some of the AC's out there have a bigger surface area. Ness, Zipper for example. I was going to hold out for one of those until I remembered that article. Looking at a Zipper beside a SE AC there is an obvious difference in size. However if you look closely and think about it for a moment the difference is not actually that big. I went ahead and bought the SE AC. Does anyone believe there is a substantial gain to be had with the larger AC's? I was told by one shop that the gap between stock and Hi-flow was somewhere between 3 and 7 HP. Come on! That's a bunch. As much as some cams OR big bore cylinders. Anybody have an opinion on this subject?
Gary

 

On the surface, it originally looked like he might have been on to something. Like maybe the resonances, etc. of the stock airbox were tuned to work "just right" or something.

Then, in a later issue, it came to light that he was doing the mufflers / air cleaner tests without having done any tuning of the ECU at all. No wonder the stock unit performed better. I believe he later put a Cobra fueler on that bike and tested it again. I wonder how the airboxes would compare with the fueler (properly set for each combination)...

 

Am I correct when I say each part of a Stage 1 upgrade works together? Why do an air cleaner with out mufflers? Why do either without increasing the fuel with an upload or something like a PCIII? It all works together.
Steve L.

 

Take your bike out for a ride with the stock A/C cover removed. The slightly enhanced feel of increassed roll on torque at freeway speeds that you'll experience will be quite similar with each of the aftermarket A/C's available. They all do the same thing...allow greater filtered flow, but none are superchargers.

 

I didn't see the article, but I can tell you this from experience, My 06 Road Glide with an "open element" stage 1 air cleaner, screams in the higher rpm range compared to the same set up covered up with the football.
Gary D.

 

Thats with a dfo adding fuel of course.
Gary D.

 

I don't know for sure if I gained any horsepower or torque, or ifit is just me. I put the SE AC (open filter) on my 06 Ultra and knocked out both front and rear baffles in the stock mufflers and it seemed to make a noticeable difference in power and a deeper sound but still not loud. I am using the stock ECM without the download and the bike runs super, no popping, nothing. I checked the plugs every couple hundred miles to see if I could tell any difference in them or difference from front to back and they look the same. as they did before the changes. Like I said it maybe just me thinking it has more power, but it does sound better than stock, the sewing machine is gone and now here is a Harley in there somewhere, I plan to add a Thunder Max, true duels, and a set of slipon's as soon as I figure out what I like in sound. I don't want loud, just the olé deep Harley sound and still be able to listen to my radio and hear my wife whisper sweet nothings in my ear. That's not asking for to much.

 

so your running no baffles mllkn6?...i've heard that's not good to do

 

Yep, that's what some of the members have said, I really don't know. What I do know is I like the sound better than stock, it seems to pull better, and I can't tell any difference in plug discoloration or otherwise. I tried it with my softail before the Ultra and it did fine with it also. But like I said I plan to put some new exhaust on before I start back riding seriously in the spring and do the fuel management thing also. The only thing I can see it changed is the sound, a little more power, and helped with the heat according to my temp. gauge, seemed to drop the temperature about 10 degrees as best as I can tell. I changed the gauge out before I knocked out the bafflesand added the SE AC, I knocked out the baffles right before my 1K check up and the tech there didn't have an issue with it. I changed the AC out a few months back, my plan was to try it to see how it did if it seemed to give any trouble I was going to the stealer and had the download installed, but since it made it run better according to my seat of the pants gauge I left it alone till the winter when I made the upgrades.

 

Good luck with that... Your ECU has fixed values for the amount of air moving through the engine at the various engine speeds and throttle openings. It makes its fuel calculations based on those values. It's still sending only as much fuel in any instance as it did while stock but you're flowing more air. Do the math. It's running lean.

With the closed-loop system that came after yours there's a limited sort of autotuning which, though not really pertinent to breathing-stuff changes, can help with them. But even with it it's not adviseable to modify things like you did without somehow compensating in the fuel department.