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Discussion Starter · #1 · (Edited)
I was all set and had the OEM filter in the cart when another track day 675er mentioned they got a BMC race air filter. I hadn't even thought about it but does any one know of any fancy air filter that track day or racers like?

If there is one do I need to re tune the bike? I'm thinking the answer to that question is no as I've never heard about needing a tune from a simple air filter...but who knows, I never heard of any specialized "race" air filters.

EDIT: The bike I need an air filter for is a track only 07 675 (stock).
:scooter:
 

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I have a K&N Air Filter on my 2010 675. No tuning needed. I am not a mechanic but from my understanding you only need to re tune when installing a new exhaust.
 

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DNA does one too, just a re-badge (kinda) of a K&N or a BMC.
Get one, chuck a new can on the rear and a new tune, you'll love it!
The paper ones suck, try breathing through a wet sock…
 

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There are scads of threads on this topic but you'll find that unless you ride your bike on the track only then the stock filter is best because it filters more thoroughly.
 

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We use MWR HE filters on all our race bike and the normal MWR on road bikes. The HE filter has a baffle over the top to distrupt air turbulance and help cut noise. Sounds like BS but we have to say it works and the top riders at last years TT races all won with these filters.
www.racingairfilters.eu/
 

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We use MWR HE filters on all our race bike and the normal MWR on road bikes. The HE filter has a baffle over the top to distrupt air turbulance and help cut noise. Sounds like BS but we have to say it works and the top riders at last years TT races all won with these filters.
www.racingairfilters.eu/
Any US distributors?
 

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Discussion Starter · #12 · (Edited)
We use MWR HE filters on all our race bike and the normal MWR on road bikes. The HE filter has a baffle over the top to distrupt air turbulance and help cut noise. Sounds like BS but we have to say it works and the top riders at last years TT races all won with these filters.
www.racingairfilters.eu/
Do the filters require a remapping? I"ll be using it on STOCK 07 675 (track only).

I understand I would get the biggest benefits if I did remap it but that isn't cost effective. Would the power benefits outweigh the negatives since I wont be remapping?

Absolutely... the owner of MWR sent me this link actually. He is also very available to answer questions and is happy to do so! :nod:
Sorry I didnt see your post. Can I get his contact info? I would like to ask him the question above....if no one knows the answer on here.

EDIT: Maybe I should actually click on thelink before I ask lol. I see there is a dyno chart on the site. What bike is that for and what mods were done? Is that a direct answer to my question?
 

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The map you have posted is one of mine, I work closely with MWR so I like to think we know what we are doing lol.
On the day the map was produced we tested two more bikes with the standard MWR filter and they we're on the safe side of not needing re-mapping and still showed power gains over standard. Both bikes had Arrow slip-ons and TOR maps. We can't say for sure your bike will be ok but if you was a UK customer with our spec bikes and climate I'd say yes you would be OK.

The map above was of a Daytona 2006 model, with MWR filter (not HE), Arrow Slip-on, Tuneboy and very small tweaks to fueling and timing. About one hours dyno time in total. The bike had over 20,000 miles on the clock if I remember right. We didn't hit the rev limiter and the blip at the end of each line is probably down to how the operator shuts the throttle at the same time as hitting the dyno record end run button.
 

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I got myself a BMC Street Filter. Absolutely amazing quality in the product. Easy install. I have heard some people with problems around 5k or so...I haven't really felt any, but we will see when warmth comes.
 

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We did some flow testing a while back on some of the more common air filters to see how well they actually performed.

The results were as we had predicted.

The more air you flow through a medium usually means that the medium is less inclined to trap the finer particles from entering the motor.

You can't get nothing for nothing, there is always a price to pay somewhere along the line.

In the case of air filters, if you want really good filtering of small and large particles you need to have fine small holes and this usually doesn't give great air flow through the filter.

Generally, the greater the air flow, the bigger the holes needed in the filtering material to allow more air to get into the combustion chambers.

There are ways around this to some extent but generally this rule applies to all filtering materials and mediums.

Unless you are racing, the stock Triumph filter changed regularly does a pretty good job.


S.
 

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I have to disacgree with you to some extent. The Triumph filter is a cost effective filter made of fibre (paper maybe). This is good to filter down to a certain particle size. A well maintained wet (oiled) foam filter is just as good at filtering for an engines needs and flows more. Sure there is a trade off if you was talking down to microns but an internal combustion engine is not that needy when it comes to filtering. The food industry filter down to the smallest of particles but the bike industry doesnt.
MWR filters and maybe other foam filters flow more than a stock one and the proof you can get gains from more air flow is in the graph above.
 

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I agree that a wet [oiled] foam filter does a great job of filtering particles and flows more air. We tested a few and found that the DNA filters were very good for air flow.
The Australian made Uniflow was another good one.

However, there is a fair bit of "hype" about air filters floating around.

Some manufacturers claims are .... "slightly exaggerated" as far as increased performance goes, as well as not filtering small enough particles to prevent internal damage to the motor.

Having said that though, I remember that we used to run all our race bikes with no filters at all, just ram stacks on the carbies and quite often ran our road bikes the same way. Amazingly, they survived pretty well...

S.
 

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An oiled filter is good enough, I wouldn't use anything else on any of the bikes.
Helpful hint though, try and limit beach racing and don't enter the Baja 1000.
 
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