Tried on dyno.
3 filters -
BMC new
OEM used(about 2000miles)
OEM new

We made several dyno pulls and get best HP number with OEM used one, mainly because every dyno pull is littlebit different. But it was about 3whp more near RPM limit. BMC filter give littlebit better hp/tq gains 3000-4500rpm but still it wasnt very big difference. All gains are very small, there is no way you feel difference, probably you dont also see it when looking 1/4 mile timeslips. Reason why many people feel gains are mainly psyhological or was previous OEM filter really dirty.
BMC vs OEM price tag is almoust same - they both cost very tiny fraction of 997tt price, I like BMC because it sounds better and looks nicer(red)

 

Really nice n affordable upgrade for ur car, imo just the same as intake systems made by others

 

thanks for posting some real world numbers. i was also convinced over time that the increase i enjoyed was largely sonic in nature .. and it isn't red anymore when you pull it out and it's covered in soot! maybe the trim part is red lol.


then we have pricing... there is something that just seems right about throwing away a soiled paper element that costs +/- 25$ vs cleaning one every time that costs 100-125$. at least if you're going to run a bmc, throw it away every time you change stuff. then you won't be blaming your oiled filters for fouled/dirty maf issues. whoops. wrong forum

 

The oil causing MAF problems is 99% of the time an OVER oiling by the consumer...not a problem w the filter itself. On the 99tt how far would you say the filter is from the MAF?

 

so i have heard, but possibly another internet rumor. but then i've had maf issues with and without bmc filters. i ruled out *over-oiling* as a potential cause. i've concluded stock mafs don't like raised rev limiters or even a bit more power.

 

By "stock MAF" you mean an untuned MAF? Iv never seen an aftermarket one....

 

Guys, my opinion is this. The BMC filter is not there to produce big hp numbers. It's there to help the engine breathe without hesitations or difficulties and keep your timming advance stable. In some cases when you run a tune and you push the car a lot then more oxygen is needed in order to help the engine achieve an almost perfect combustion along with added fuel. Your stock filter will limit that and so your car's engine will be pulling back timing.
Just another example. If run a tune in your car and you decide to add a pair of larger intercoolers without any further tuning, you won't see any difference on the dyno or even if you see it will be negligible. But when you push the car you will feel that the car has a more stable performance, no hesitations and its timming advance is using more aggressive numbers while at the same time your stock intercoolers at the same conditions might have already pulled back timming due to heat soak. Those things you won't see on the dyno. So some parts produce a side effect to adding power rather than a direct one.
A free flowing exhaust with race cats has a direct effect to increasing horsepower and an indirect one. The direct effect is the fact that the gas flow increases, the back pressure falls so hp increases for that matter. Let's say you get 40hp crank. It's not only that. You get another indirect benefit. You keep your timming advance stable or even see more agressive numbers simply by keeping your egt's lower! That's just my 2 cents. I am by no means an engineer so feel free to correct me if I am wrong.

 

Funny how these BMC threads keeps cropping up from time to time...

I note OP didn't provide any actual numbers or charts quantifying his findings, so not sure what numbers are actually being referred to but would be interested to see any supportive hard copy particularly the one where a tiny gain (the one that could never be felt lol) was quoted to be existing in the midrange. OP do you have the figures and hard copy?

This is actually very unusual because if the oily filter was indeed better flowing better anywhere it would definitely manifest a gain at the max rpm point where the engine is at it's absolute maximum air intake level. You see any improvement must at the very least be shown at max rpm especially if comparing against a filter that is "allegedly" stifling intake. So that one totally defies logic from an engineering sense.

However what is logical and believable is that the stock Mahle filter would most likely produce better HP than the BMC and without any of the fuss or nuiances associated to maintaining these antiquated oily filter substrate arrangements. The OP mentioned the OEM paper filter showed a gain of 3 hp at max rpms in comparison.....now that's quite an indictment guys....sorry.

Btw i'm curious how many users out there really know when their oily filter needs washing out and, how much oil to reapply? I'd be interested to hear the formula behind this one? Most know Mafs become an issue where any oil fouling is concerned....can't escape that fact....and then there is the potential for particle contamination.....can't escape the fact either, and there is no such thing as 100% removing the particulate trapped in these oily filters (or any filter for that matter) when you do wash them out because some of the particulate will always remain and/or transfer onto the opposite side of the substrate during that process. So there is always the possibility of dislodgement. Kinda makes the OEM throwaway look pretty sensible. Could never get my head around the user that can afford the Porsche Turbo but not the air filter lol. I mean that's classic. And to risk longevity of an engine like this? ...well you'd really need to be getting a seriously good gain from the exercise to warrant that imho.

Fwiw some may find a few of these links interesting...

Pay attention to post # 8 https://www.6speedonline.com/forums/...ter-4-gt3.html

Take a peek at post #13 and #17 from Affastyle2000....http://forums.audiworld.com/archive/...t-2678036.html ...no such thing as a good AM cone filter..

Bottom line: Todays paper air filtration technology is actually far more advanced than what many choose/want to believe. Maybe the AM should consider offering a red paper filter for the motoring enthusiast?...just a thought...i mean if colour gets a sale over the line...i like it!...and it could save the engine which has got to be a good thing. A bit like the nicorette. The cigarette you can smoke without the cancer.

It's interesting how users of these filters are prepared to compromise the longevity of their engine in the faint hope of achieving something from the exercise. Can't understand that. Sorry guys.

 

P, did you know the OEM GT3RS 4.0 filter uses a cotton/oil element sourced from Porsche Motorsports?



and Cup cars use this?

 

Porsche sources their filter elements from...

 

Yep. Saw that in an earlier thread. Does it change anything? Not imo.
What i do accept is a race car engine does get pulled down more frequently than any street car engine so certain compromises are understandable.
Bottom line is does the BMC filter produce power?. ...well in the cases we've seen so far there has been enough to show it doesn't do anything at all other than pose a potential compromise to the longevity of the engine, mainly due to user error and/or lack of experience or knowledge of how to properly clean and oil it to ensure the filtration is up to par with the OEM paper. As i said, let's see the hard evidence there is any gain, and then one can evaluate is that gain worth the hassle and risks..

PS. Funny how sharkster didn't have any gain at all in his powered up 3.9 GT3. I'd have thought he would have known if there was one.....need i say more...

Edit. I note the 4.0 is a track focussed car Porsche pitched at the hard core track day enthusiast. As is the case with the BMC filter in that car, do the racing stripes make it go faster too? These are dress frills to enhance the general appeal of the package to the market in which the product is being pitched at.

 

I think modified forced induction changes everything.

If I had a dyno, I'd run a car using larger turbos or tuned electronics back to back with and without a paper element.

As far as mucking up the MAF - I pull my sensors with every oil change, spray them with CRC, and wipe down the inlet pipes. I've never found significant gunk inside the inlet...but I've never re-oiled my filter.

 

No offense but i think you are grasping at straws. Ask Mahle filters why they don't make these. They don't need to.....better filtration technology that will produce better allround outcomes. Same answer with Mann and Hummel. It's all about creating the best outcome for the engine.

I still come back to the fact there has been nothing tangible put on the table to this day to suggest there is any gain whatsoever on a 997tt, least of all one of any notable significance worthy of the faffing about and potential risk to the engine.

Don't forget the position of the air filter in this car is at the rear of the rear end.....the worst place possible where for airborne particulate. You will note even that cup car has the filter and air breathing through the lid sealed with a rubber bellows. With a street car there are so many more variables than what you'd ever see on a racetrack...

 

this will seem rather unscientific, but most of my conclusions on subjects such as these, have been reached through my own version of trial/error and i'm just a guy who drives, but i have had two of these freaking airfilters and cars lol. the bmc filters are usually filthy, when i cleaned/replaced, and the stock filter isn't ( as bad ). i just don't want the difference in my motor! it's NOT worth it, in my view. if i had a new cup car i'd probably also have a crew/team helping me offset the cost of filters and my motors, should one fail. i certainly get that breathing in a car with twin turbo's is a big deal. doh! that's probably why my airbox is cut. but so is dirt/soot/grime. a visual comparison over time, coupled with no genuinely discernable increase in POWER, has helped me in my decision to return to a stock filter, until such time as i decide to get rid of the stock airbox and intake. again, it *FELT* faster* ( intake/spool etc ) with the bmc, but..whatever. just my .02, but i'm probably up to a buck by now. carry on.

by the way.. what oil you guys use? ( kidding )

 

a voice of reason in a chaotic world. sometimes sh*t is just that simple. very much enjoyed the gt3 oiled filter/racing stripe analogy also. on point.