Anyone tried pulling airbox for open filters?

Markermc · 11-16-2002, 08:47 AM

Just thinking about ways to get more air in there without having to spend $400 on a CF tube to run up inside the fairig, led me to wonder if anyone has ever tried just running K&N filter "pods" off the ends of the Intakes with the entire airbox removed?

I know all the stuff about what the engine's negative response could be... flat spots, etc, so that's why I was wondering if anyone knows for sure by actually having tried it.

It would just seem like a logical way to get the air filtered with a lot less restriction on the intake... and make a nice intake howl too.

Mark

jclark · jclark's Garage

You have to remove the swingarm to remove the airbox ( unless you M80/100 the thing out )

A lot of work, but for someone so inclined...

jeff
not going that far, but putting the semi-stock exhaust back on for Laguna Seca next Monday, hehehe....

SilverR1100S · 11-16-2002, 09:04 AM

Hi there

Mark I agree with you
never tried it but I'm thinking about this change all the time.

There is a PIA R1150 GS with these air filters.
It looks very nice and they clame a hp profit.

I'll keep this post in mind and hope to see a lot of response.

see you
Coos

Markermc · 11-16-2002, 09:05 AM

After looking at it for a bit, I figured it would take a bit of wrangling (with a dremel tool and hacksaw) to get the thing out of that tight spot it's in.

Mark

tominator · 11-16-2002, 04:40 PM

I bored 3 X 3/4 inch holes towards the back of the snorkel that feeds into the air box. Seems to feed a little more air. But feel this cheap alternative would be more of an advantage with the SJ power filter. BTW I'm running the K&N stock filter replacement unit.

Miss the growl often heard after adding the SJ Power filter and Lennie's Air duct!

Will have to wait $ for that combo....

Works for me.

Cheers
Tomas

brad black · 11-17-2002, 01:06 AM

the first reason for not doing it is the usual bmw build the bike around the airbox.

the other is that, at higher speed, the pods will be in a vacuum generated by the high speed air flowing around the bike and your legs. it may well work at low speed, or on a dyno, but it will upset high speed stuff.

mainly with inconsistancy, more so than the lack of performance.

there was a kawasaki zrx1200 - ???, the naked thingy - running in a formula extreme class out here where they ended up putting plates between the back of the engine and the leading egdes of the side covers - effectively creating an airbox - to smooth and slow the airflow around the pods they had fitted. it looked a bit odd, and must have caught much of the hot air coming off the engine, but it made high speed jetting consistant, and was a lot faster for it.

maybe they should have kept the original air box, but they probably threw it away without even considering it might work.

depends on the speed being ridden at. it would be easy to upspec the s air inlets to feed the std airbox if you were serious.

so - re my comments that have upset others before - why don't you try it, and let us all know. maybe you could do a chip to suit?

brad

Eron Flory · 11-17-2002, 07:20 PM

Brad is correct on his comments about the cylinders upsetting the air flow around the intakes. With a good intake and air box you will have a positive pressure in the intake instead of a negative pressure. I did extensive dyno work with both of my 2 valve BMW racers and never got more power on the dyno than I got with a good air box and that was backed up by the on track performance also.

Think about this, when was the last time you saw a superbike or GP bike without an airbox?

I'm not trying to discourage you from experimenting because you will no doubt learn something from whatever experiments you do. I'm just trying to let you benefit from someone else's experience.

Eron

brad black · 11-17-2002, 08:55 PM

people often get a bit carried away with the ram air theory too. imo, ram air helps more by supplying the airbox with a ready supply of air. not ramming, but not letting a vacuum form. the 916 race bikes were quite a bit faster than the old 888 bikes, even with around the same hp when the 955 corsa first appeared. the 888 used to create a vacuum in the airbox at big revs, the 916 had a very nice air supply to it's airbox, with much better results.

you could try removing the r1100s airbox, and then build an open front/top box behind/beside the pods. this way, you could effectively increase the size of the airbox,but still keep still air around the pods.

this still air is the key. how much better it will go is the question, and whether it's worth the time it takes to get the std box out will be the decider. i'd hate to have to put the std airbox back later.

i'd work at getting more air to the air inlet at the front, or more to the top of the filter.

brad