[dtc100]

I guess the consensus is if the manufacture limits the powertrain output too much, then an aftermarket performance product can be money well spent, if the car is tuned well from the factory, then not.

I read the N52s are tuned generally in three different models by BMW, with the new gen 5s having the most powerful N52s in them. Supposedly the more power is achieved by (I quote from Wiki): "With a common engine displacement, the output changes result from the omission of the variable resonance system, dual plenum intake runner system, and the variable back pressure muffler."

So BMW itself uses the common intake and exhaust performace enhancing tricks to unleash more power from the same engine, while keeping the lean fuel mix and valve timing intact. Am I correct in such assumptions?

[benzo23]

Wtf are you people talking about? Didnt you read the damn box? FEEL THE POWER!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!

[PAKMAN]

NA is not FI. You cant expect to get 20HP off of a K&N filter. It's just common sense. It is so much easier to tune a FI than a NA. K&N is definitely not cheating us. Their filters are somewhat better than the stock because it does give you +HP one way or the other.

[dtc100]

Originally Posted by TrackRat

NA or FI has nothing to do with an airfilter delivering more HP. If the airfilter isn't a flow restriction in the induction system you can remove it and there will be no HP increase, just more dust entering the engine.

The dyno does not lie and countless times it shows zero power gains with many hyped products.

Is the BMW Performance Intake a hyped product that gains nothing but maybe a little more sound?

[dtc100]

Originally Posted by TrackRat

A properly operated engine dyno will answer the hypothetical questions.

Getting everything your engine has to give. The BMW Performance Air Intake System captures all the air your engine can possibly use, then introduces it as evenly as the engine can possibly use it, in the highest possible density. It generates more complete and more explosive combustion—and a fuller expression of your engine's sheer power and torque.

Upgrading to a BMW Performance Air Intake System will unleash gains of up to 3 horsepower and 3 ft-lbs. of torque, while also helping the engine to operate more efficiently with a 30% reduction in back pressure and increased overall performance.

This dynamic breathing system was developed with computer simulations that revealed the optional size, shape, number and position of pathways that not only allow, but actually inspire the most unrestrained flow of fresh air.

The end result is a vehicle that responds to throttle inputs more robustly, and accelerates more energetically. It is not a coincidence that the innovative BMW Performance Air Intake System even makes your BMW sound faster.

It sounds to me BMW is saying its stock air intake is restrictive, also creats 30% more back pressure, and the performace air intake removes such restrictions.

[osusports216]

Should we go AEM intakes?

[Psukhe]

Originally Posted by dtc100

Is the BMW Performance Intake a hyped product that gains nothing but maybe a little more sound?

More than likely, yes..... and with a hefty price tag too.

[dtc100]

Originally Posted by Psukhe

More than likely, yes..... and with a hefty price tag too.

Price aside, BMW does make a few claims, one is up to 3hp gain, of course you wouldn't feel much of it if it is only 1 to 3hp.

But the 30% reduction in back pressure is a pretty specific claim meaning the stock intake has 30% more back pressure than the performance intake. Assume BMW is correct then the stock engine does have a restrictive intake. Except that with all the restrictive elements removed from the stock intake the most gain one can expect is about 3hp.

[Psukhe]

Originally Posted by dtc100

Price aside, BMW does make a few claims, one is up to 3hp gain, of course you wouldn't feel much of it if it is only 1 to 3hp.

But the 30% reduction in back pressure is a pretty specific claim meaning the stock intake has 30% more back pressure than the performance intake. Assume BMW is correct then the stock engine does have a restrictive intake. Except that with all the restrictive elements removed from the stock intake the most gain one can expect is about 3hp.

But that is making a possibly erroneous assumption that the engine will actually benefit from that 30% change. I can remove the intake completely and let's say have an 80 or 90% increase in possible flow -- but that doesn't mean that the engine can actually effectively use that increased flow.

[dtc100]

Originally Posted by Psukhe

But that is making a possibly erroneous assumption that the engine will actually benefit from that 30% change. I can remove the intake completely and let's say have an 80 or 90% increase in possible flow -- but that doesn't mean that the engine can actually effectively use that increased flow.

This is not an assumption rather a claim made by BMW.

You can dismiss such claim, especially if you have proof to the contrary. BMW did say there is improvement of "up to 3hp" gain, in part because of the 30% reduction in back pressure. Of course even if the BMW claim is true, the benefit/cost probably is still not there. It did however support the assumption that the stock intake may be restrictive.

The question is then, would a high flow filter like the K&N remove a lot of such restriction? If it does, at $50, it is a different ball game.

[lucas.kent]

I love how there are 39 posts in here and the OP is nowhere to be found...

[dtc100]

Originally Posted by lkw15

I love how there are 39 posts in here and the OP is nowhere to be found...

It was pointed out very early on that he used a K&N diesel intake in his comparison by mistake.

BTW, the BMW performance intake for the US uses a high flow oiled filter just like the K&N, it retains the second half of the stock intake box with the charcoal filter intact. The difference is it uses its own front half box to fit a bigger air intake track, and there seems to be some kind of additional air track that will allow excess air to flow out of the intake box from the back end. Correct me if I am wrong.

[Dark_Knight_335]

Originally Posted by lkw15

I love how there are 39 posts in here and the OP is nowhere to be found...

And booked. He planted his seed- he fulfilled his purpose.

Get a clue fellas, and heed the sign:

[Cygnusx1]

What about magnets on my fuel lines? And what shape?

[dtc100]

In conclusion, both the BMW Performance Intake and the Dinan Ram Air Intake use a high flow oiled filter, both in their own ways increased the size of the intake air flow path, but left the post-filtering air path unchanged.

It seems once you use a drop in high flow oiled filter, the stock air intake track becomes a limiting device.

[TSM330i]

Originally Posted by F104

http://www.e90post.com/forums/showthread.php?t=443917

What's really odd about this is that when I was a filtration manager for a hydraulics manufacturer, we would test filters using ISO test certifications and the paper elements were ALWAYS the worse. There is NO way to control the "opening" or size of the particles the filter would let pass of the filtration media with a paper element, that's why they use "nominal" rating on paper elements.
The filters we manufactured used a synthetic media (similar to K&N). These elements could be certified down to 3 micron absolute rating. They would crush anything that used a paper element. Our media was so good, that we were a supplier for dialysis machines (not the same media used for hydraulics).
Another advantage with the synthetic media over the paper elements was that the synthetic media actually had a depth to the filter. Paper had no depth to it at all and once the element "caked" that was it. The dirt holding capacity was greatly reduced using a paper element as well when compared to a synthetic media.

This test makes NO sense to me what-so-ever. Yes, I worked as a hydraulics engineer for 12 years and with our servo-valve systems we designed we would NEVER use a paper element. A $15,000 valve would be toast in a matter of minutes from all the particles the paper filter element would let through.

[dtc100]

The IC engine can tolerate particles well. Some oil filter manufactures would actually advertise the ability to filter up to 3 to 5 micron, a size much larger than any air filter would allow.

[TSM330i]

Originally Posted by dtc100

The IC engine can tolerate particles well. Some oil filter manufactures would actually advertise the ability to filter up to 3 to 5 micron, a size much larger than any air filter would allow.

What are you talking about? 3 - 5 micron absolute is one of the highest performing filters available. They also cost much more than a nominal element.
3 - 5 microns is not going to be larger than any air filter would allow. Not by a long shot.

[dtc100]

Originally Posted by AW325xi

What are you talking about? 3 - 5 micron absolute is one of the highest performing filters available. They also cost much more than a nominal element.
3 - 5 microns is not going to be larger than any air filter would allow. Not by a long shot.

My bad, went back and checked, should have said 10 to 20 microns. The point is even the high flow filters can already filter out particles many of the oil filters would let through.

[RichReg]

Hey guys...
..slightly off-topic but I just got the K&N filter for my E90 330i (33-2332) from AutoAnything.com.

If anyone's interested call them & ask for the 15% off coupon code;;
(one-time use only). It will only cost $42.72 w/free shipping.

[veloSpeed]

For the most part, you're all getting a placebo effect from these K&N filters. It's all in your head if you don't read the numbers. Someone with a Dyno, help!

When you buy a finely tuned machine, why would you want to cheapen it? Too much time and money wasted on bogus claims. Do some real research and NEVER, EVER believe the aftermarketer's claims. They're simply trying to make money to finance their next scam. Keep it real, make it last, keep it stock.

[darkrom]

Originally Posted by Wires

On any modern vehicle a CAI is a giant waste of cash. You need to be doing it for the bling factor. Any gains are typically in the last couple hundred RPM before redline.

The manufacturer spends a lot of time minimizing air intake restrictions (free HP), and balancing that with resonators to minimize intake noise. So losing the resonators and going straight CAI does net gains, but minor.

I put a K&N in my 335xi, but did it for consistent air flow and the ability to clean it. I've did K&N's on all my vehicles as well, and my butt dyno has confirmed what others that have did true dyno's have said: Minimal gains.

If I was to guess, they run a dyno on an engine with an air filter with "x" miles on it (so the filter is pretty plugged). Then they run the CAI setup on that same engine with those same "x" miles on the K&N filter. What you find is the K&N will keep consistant flow, were the paper one chokes up (hence gains over stock). That's probably where they get their 15-20HP gains. If you swapped your stock filter on a regular inteval, you'd keep the power that the K&N is "giving".

That being said, I'd still buy another for my next vehicle, but it would be for the ability to clean it.

Smartest response in this thread!