[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Old air filters for R1100S needed

Reply from Ben:
> Many thanks, Wendell, first I've seen Don Eilenberger's curves. Many more
> curves and quite a lot of discussion can be found at Moto One
> http://www.moto-one.com.au/performance/index.html
> Reading dyno curves takes some care. The eye is easily fooled and 
> sometimes
> dramatic vertical increases (in HP or torque) are not eye-balled right or
> not recognized in proportion. In other words, large practical changes at 
> low
> and lower rpm (which matters most to most of us) are overlooked.
> Because the time course of the runs is not known and couldn't be much
> controlled in any case (I have some experience with /7 dyno testing),

Don has not some but A LOT of experience with Dyno testing

> it is
> not clear how the curves really relate to ECU performance apropos the O2
> sensor or, for that matter, how surging arises as the bike settles into
> steady-state when on the road or how the two really relate to one another.
> Although I thought it would be uncivil earlier to offer my baleful opinion
> on K&N filters, I would now like to comment with the following well-known
> facts:
> 1. you can't make a change to any single thing in your stock aspiration 
> and
> ordinarily expect an improvement,
> 2. paper filters are a pretty good compromise practical solution from the
> point of view of manufacturers and
> 3. all things considered from the point of view of do-it-yourselfers, 
> oiled
> foam such as Uni (not K&N  which is oiled gauze) breathes well, cleans 
> well,
> provides hands-on feedback on your machine and keeps you in control, and 
> is
> far cheaper.
> In the test you mention, Eilenberger blocked 50% of the air intake (which 
> is
> a pretty meaningless thing to say) and expected 50% reduction in power.
> That's plain nuts. I feel you are wrong to take his point seriously.

I think you will find that Don was trying to see if 50% reduction would have 
ANY not 50% reduction in power. Showing  the stock filter still had 
sufficient surface area to adaquetly filter air without degrading 

> What he did find, but did not interpret, was a large reduction in power 
> and
> also, oddly, a fairly clear reduction at lower rpms...which you'd never
> expect. That certainly suggests that the front-end breathing is impaired 
> (or
> at best, marginal) in the stock form but the degree of impairment and the
> benefits are hard to guess.

I don't have enough knowledge of Dynos to see what he missed interpeting.

> Moto One are quite enthusiastic about improving the intake path with
> megabuck bits of plastic but others definitely are not. For sure, the 
> intake
> is often part of the tuning (although I personally view intake or exhaust
> "tuning" to be unsound outside of racing). So changing the front-end
> breathing is likely to make some changes somewhere, given the typical 
> tuning
> logic of modern bikes. Sometimes even introducing restrictions can be
> beneficial to some part of the curve.
> Having said all that, would somebody PLEASE let me know if the ECU 
> corrects
> for changes in filter resistance (other than the obvious if just 
> occasional
> presence of the O2 feedback)?
> Cheers.
> Ben
> -- 
> Ben Barkow, Toronto... 39 seasons on Beemers, 44 as a biker,
> 1961 R69s/rod, 1967-1999... really sup'ed up and fast
> 1984 R80RT/rod, 1998- 5 extra peak ponies in a wider flatter power band,
>  much modified 2-into-1 exhaust, CR 9.5, Keihin PJ 34mm oval carbs,
>  Uni filter, dual-rate springs with cartridge emulators,
>  BT45/S11, Saeng fairing
> 1999 R1100S, 2004- Leo Vince exh, JetHot coatings

I will forward this to Don and see what he thinks.
Bill Kenney
formerly 96R1100RS