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Re: Old air filters for R1100S needed

Tom B, we really can do without your patronizing, "I see you are at it
again." Isn't that sort of "argument" somewhat beneath you? And I think if
you took a few minutes to READ my post, you would have noticed that I am
pretty negative about K&N filters or for that matter, any single-change mod
- - as I explicitly said. You are also talking through you "hat" when you say
the feedback loop cuts in a certain rpms. You DID read my post before
shooting from the lip, eh?

I also think you owe all of us an apology for posting your elaborated
opinion that I must be intending to go into business selling junk to my
biking friends. Gimme a break. Aren't there chat rooms for that kind of
nonsense accusation?

Tom B - do you think everybody else here is a moron? Or do you respond well
only to loud blow-hards like yourself? Shape up.


As I may have mentioned before, a really excellent book on EFI is Adam
Wade's "Motorcycle Fuel Injection Handbook," 2004. But he excoriates Bosch
for their bashfullness.

Very nice of some to post what they WISHED Don had said. Don is a very
excellent contributor who I greatly admire, of course. I don't say this just
because in his generous reply to my post, he appears to agree with me on
just about every point.  But what he wrote was:

"We... tried one final test to see if the mixture was lean.... This test was
blocking 50% of the intake to the air-filter-housing (the snorkle on the
R1100R.) The theory is - that the blockage will force the mixture rich, but
I question if this is true on a Motronic system using an O2 sensor to adjust
the mixture:


As noted - I believe this test is inconclusive, but the reduction in power
is not 50% indicating that the R11 is not starved for intake air."

I didn't notice anything about Saranwrap around the airfilter, just some
uninterpretable remark about blocking the snorkles 50% (did he cover 50% of
the intake hole which should have a neglible effect or fill in 50% of the
duct for its full length, 50% of the filter, what?) and truly expecting a
50% reduction. As I said, that's nuts... but big changes did result.

It is also seems to me that Don is not on the mark as to how the ECU uses
the O2 yes/no signal. Also in Don's post, he talks about dyno timing - see
below. I can't claim to understand our ECUs either because Bosch is
secretive about it. But I do know that the O2 feedback does not come into
play until the bike settles down into a steady state whose parameters I do
not know. And then, I am told, it samples the O2 sensor at a very lazy pace.
I have heard that sporty riders rarely fall into the steady-state mode
because they are constantly adjusting their throttles.

Don is sort of right about dyno timing with upper-gear roll-on testing. But
the truth is, you can zoom up and down the rpm scale at any pace you please.
The point I was making is not that you can vary dyno timing so much as none
of us know about the O2 feedback loop timing. My guess (pure guess) is that
the time constant is way out far beyond the rate at which dyno testing is
done - you'd heat up the whole garage if you went that slow. Just a guess.

C'mon folks, less flame for flame's sake and more thinking. Let's be

Kent presents a reasoned defense of BMW. Fair enough. I think manufacturers
want to do what is best for themselves and that often means what is best for
their customers. But the two needn't correspond. For example, it is clear
that all bike makers want impressive HP figures which means at peak rpm.
That is quite different from what most riders want which is a torque curve
like some electric motors with peak torque at stall and a flat, drivable

For air filters, it is inconceivable for any mass product to have an oiled
foam filter because they require ongoing attention. Paper is OK but oiled
foam filters better, breathes better, does not have rain problems and is a
mess to clean (hey Tom, notice that apropos your snarky (and ignorant)
remark about rain?). K&N is OK too, but doesn't filter well. I've done a lot
of filter testing with my homebrew airflow box and Unisyn airflow meter
which I needed for tuning Webers.

Thanks to Tom Cutter. But it still leaves the question of what CAN be done
to "fool" the ECU when mods are made? For sure, we can "tilt" the TPS. I
once hung a tiny light bulb on a timer under a room thermostat....

Ben (snow as high as an elephant's eye in Toronto)