Air box lid....

BLZ2DWL · #1 (**permalink**) 09-01-2005, 03:22 AM

I got a K&N filter, DU-9098 (it seems to fit, this is the right one?), and I cut the top out of my lid. The problem is that the remaining ring of the lid is not strong enough to do anything. When I clip the plastic ring in, it just pulls away from the filter. Any ideas on what I can do without spening a bunch of money? Anyone got a spare lid I can use? Thanks for the help.

Brennan

brad black · #2 (**permalink**) 09-01-2005, 01:43 PM

get a new lid and cut out less. they're not very much new and even less from a second hand supplier.

enigmamdw · #3 (**permalink**) 09-01-2005, 03:14 PM

Next time just cut out the area between the two nozles...that's what I wish I had done.

You are not going to benefit from opening it up any more than that. Just taking the little snorkles out of the lid is really sufficient...however the sound related to opening the box up a little is worth it.

AndreasMet · #4 (**permalink**) 09-05-2005, 01:14 PM

Hey thanks for the advice on the snorkles. I removed those and although there has been no increase in power, or top end, the sound is much improved.

Question: what will removing more of the box do? Even better sound?

900DucRider · #5 (**permalink**) 09-06-2005, 12:38 AM

Mine is fully open and I get a nice whuuuuuump sound when opening it wide open.

I have a spare full lid with snorkels if you have something to trade. Which bike is this for?

BLZ2DWL · #6 (**permalink**) 09-06-2005, 03:46 AM

For a 99 900ss. I've got snorkels if you've got a lid. Thanks...

Brennan

900DucRider · #7 (**permalink**) 09-06-2005, 04:48 AM

don't think mine will fit, its from a '95

enigmamdw · #8 (**permalink**) 09-07-2005, 05:32 PM

Yes the sound will improve even more the more you open up the box.

There is a negligable performance gain by opening the airbox more than say half of the lid.

opening the lid more than that will have no effect what-so-ever (cept sound)

the engine can only suck so much air at a time and while you can't really open in up "too much" you will not benefit performance-wise by opening the box up too much further. I had at one time the actually numbers and all the logic behind that saved somewhere but I have since then crashed two HD's so I no longer have that info handy....I'll look around for it.

redduck · #9 (**permalink**) 09-08-2005, 03:29 AM

Quote:

Originally Posted by enigmamdw

Yes the sound will improve even more the more you open up the box.

There is a negligable performance gain by opening the airbox more than say half of the lid.

opening the lid more than that will have no effect what-so-ever (cept sound)

the engine can only suck so much air at a time and while you can't really open in up "too much" you will not benefit performance-wise by opening the box up too much further. I had at one time the actually numbers and all the logic behind that saved somewhere but I have since then crashed two HD's so I no longer have that info handy....I'll look around for it.

Same with me. I had a link to a site that did an excellent job of explaining where the real performance gains came from by opening the lid. I do remember that any performance gain had more to do with decreasing turbulence inside the box than it did with gross airflow gains by virtue of a larger hole... Something called the Helmholtz theory. With a closed lid, you get shock-waves from the intake pulses bouncing off the top of the box which would cause a resistance to the incoming air. This limited how much air could actually get into the throttle bodies at high RMPs. It made perfect sense when I read it. True, the engine will only suck in as much air as it can. The trick with the open lid is to eliminate air turbulence in the box so max air goes straight in. It has been several years since I made this mod myself, but in my personal experience I do remember feeling an improvement. My first hard ride with the open box, I ripped the throttle to wide open and it went right into the rev limiter. It spun up scary fast compared to how it performed before the lid was opened. It was in keeping with the theory. The performance gains will only really be seen at high RPM and with how fast the engine can get there... Oh yeah, it sounds wicked cool too!

edwyun · #10 (**permalink**) 09-08-2005, 03:39 AM

Another question is, when cutting the airbox, whether to create one large opening or cut many medium or small openings.

redduck · #11 (**permalink**) 09-08-2005, 03:52 AM

Quote:

Originally Posted by edwyun

Another question is, when cutting the airbox, whether to create one large opening or cut many medium or small openings.

The Ducati Performance piece is one large hole. They leave about 1 inch of the forward lip to help keep water out.

Kennedy · #12 (**permalink**) 09-08-2005, 03:18 PM

Right. I'd look at the airbox when the tank is down. Leave the part that sticks out in front (a few inches where the airbox top has a bend) and cut behind that. BCM once recomended drilling about a dozen 1" holes behind that point - try that too if you like. That way if you want even more open you can just cut that area out. You may need a remap though if you've got slip ons or a full system and then decide to hack the airbox.

edwyun · #13 (**permalink**) 09-08-2005, 05:18 PM

Quote:

Originally Posted by Kennedy

BCM once recomended drilling about a dozen 1" holes behind that point - try that too if you like.

That's what they did to mine and it works fine and prevents moisture from entering the airbox on wet riding days.

enigmamdw · #14 (**permalink**) 09-08-2005, 05:51 PM

Cutting small openings will cause turbulence in the air...disrupting the flow of air. Which won't help you at all. The mail reason for taking out the cones and connecting the holes....help even and smooth out the airflow.