Pete Lech

I have seen references to the BMC Air filters, which AJUSA sells along with a drilled out airbox cover. I am familiar with K & N filters. Are these two filters basically the same? Do both fit into the stock airbox?

I hate to drill out the stock airbox. Are there any used ones available, or does everyone else have the same idea as I do? What is the cost of a new cover?

TIA

Robin 993DX

The difference between K&N and BMC is that K&N is made in USA, BMC is made in Italy. And also the K&N filter for the 993s have been recalled and discontinued by K&N long time ago (maybe 2 years ago) and K&N have not produced a filter solution for the 993 cars since.

Dennis Mitsch

When I received my C4S, it had a K&N in it.

Having heard of the recall here, I purchased a BMC filter as a replacement, therefore I had the opportunity to hold both in my hands at the same time.

The actual filter material seems very similar, the main difference was the rubber surround.

On the K&N, each side of the surround was a separate piece and then bonded together. On mine, it was disintegrating at each corner, with bits of rubber falling off.

The BMC filter appears to be fabricated from a continuous piece of rubber.

It has been in my car for a year, and shows no signs of disintegrating like the K&N.

Dennis Mitsch - dem@haphazard.com
My cars - http://www.haphazard.com/dem/porsche/
The 993 FAQ and Knowledgebase - http://www.haphazard.com/993kb/

Viken

The bottom line is that there will be no performance gain from either filter.

STLPCA

It's my understanding that was the reason for the recall by K&N - the danger of sucking in rubber particles.

BTW, although I have used K&N on other cars (not my 993) w/o any problems, I've read a few tests over the years all finding K&N did not filter as well as oem paper filters & offered negligible (if any) power increase.

Pete - used airbox covers sometimes pop up on eBay & sell pretty inexpensively. However, I haven't heard of anyone who didn't like the Motorsound/drilled cover sound.

Anir

Of all the snake oil upgrades offered for our cars, the K&N filter must be top dog.

Think, for a moment, how ridiculous it would be for an engineering firm of Porsche's caliber to spend decades creating one of world's classic performance engines - only to choke it with poor filter material at the front end. What would be the rationale?

Maybe, the cone-shaped K&N filters offer some negligible improvement in air flow on some restricted, non-performance engines. Even in those cases, I bet the gains are tough to document.

Garey Cooper

Hi Pete;

I have a K&N Cone filter in my car. I tried the K&N filter for the standard airbox but the rubber flange was too thick. It would not fit into the airbox and allow the snaps to come back down.

The horse power claims for the K&N are something like 5 or so, well below what you could feel. And also so low that the increase would be difficult to measure, it would be below the resolution of most instruments that could be employed.

What I do like about my current set-up is the sound. On WOT it just adds a fierce note to the intake that you can hear in the cabin. The car (this comment includes the change to the exhaust) also feels a little less "choked down" with this set-up. This is entirely subjective and the only comparison I could make is that it is similar to how the european cars feel when you rent them overseas as compared to thier USA sold counterparts.

As to whether or not they do filter well, who's to say? Try it for 150K miles and then measure the difference to a motor of the same mileage with a stock filter. I note that lots of racers use them including the desert guys so they must do something.

I can't comment on BMC, never used or seen one in person.

By the way you can pick up the motor sound airbox covers from time-to-time on the Rennslist classifieds. It is the stock airbox with lots of holes drilled in it and a chrome air intake horn.

I'll try to attach a picture of my K&N set-up so you can see how I did it.

Anir

Garey,

Thanks for your objective post. How do you think the sound compares to the factory motor sound option with respect to an improved intake noise?

Joe@Fabspeed

The only difference between BMC airfilters and K&N filters is that BMC uses red silicone rubber outter edge material that is formed in one piece and it is resistant to cracks and failures. Reoilable and resuable. Fabspeed is the largest East Coast dealer for BMC Porsche filters.

If you want to add more sportscar sound and make a POWER increase that is real and infinetely better than Motorsound 993 airboxes or a few small random holes in a 993 airbox (you need to cut it all the way open to make power- not pretty and then not salvagable afterwards) then take a look at these CARRERA CUP AIRBOX COVERLIDS! Guaranteed significant power and sporstcar sound to all 993s. Special RENNLIST member discount and available in Carbon fiber, Carbon Kevlar, or Silver style. Integrated performance packages available with hiflow exhaust, matching chips, airbox, and or catbypass pipes. Inquire.




Fabspeed Motorsports
www.fabspeed.com
215-646-4945
info@fabspeed.com

Garey Cooper

This is to reply to Anir's question about the difference's in sound from my set-up to the factory motor sound option.

Basically I can't help! I haven't ridden in a 993 with the motor sound option so I'm not able to make a valid comparison sir. Sorry.

STLPCA

Assuming you meant to say a significant power increase, can you quantify the "significant" power increase that Fabspeed will guarantee just from the airbox mod?

os993

I've had the Powerflow K&N Cone filter on, as well as a heavily drilled factory airbox with factory filter. I was looking for a better sound (95 993), not necessarily increased performance (hey, I'm realistic). Also, I have Fabspeeds oval tip mufflers on.

Conclusion? Drilled out airbox sounds MUCH better!!!! Yes, believe it or not (I didn't at first). Sound better at idle (deeper sounding and more gurgling. Cone filter just sounded like a big air leak). At WOT, both are the same!!

In addition, I hated how the cone filter can get wet, and I didn't like how the clutch vent was connected to it.

Save your $$$$, and drill out the box!

Joe@Fabspeed

If you drill your stock airbox, that means that if you ever wanted to sell your car, you would most likely have to buy a new $120 replacement Airbox lid from Porsche. Why drill your stock 993 airbox WHEN you can actually buy a cool new Fabspeed Carrera Cup Airbox Lid in carbon, carbon kevlar, and polar silver.

In reply to Dan 96C2 St.Louis , a 964 was dynoed at Porsche Motorsports with and without the Carrera Cup Airbox Lid, and not only did it give the car a better sportscar sound, but the stock 964 also gained a legitimate 8 horsepower, no smoke and mirrors. On 993's, we have seen 8 horsepower, and with free flow exhaust systems, we have seen even more power gain. These airbox lids from Fabspeed are one of the easiest and cheapest way to improve your Porsche. There is no reason to be a grouchy skeptic.
Come to any race track and find out for yourself. Have a great day!

STLPCA

Hey Joe-
Don't be so defensive. Although I'm not the least bit grouchy (& don't know why you would think otherwise), there is good reason to be skeptical when anyone (not just you) claims add on power from a product they offer for sale. Especially when others have questioned such claims in the past. I think my question was perfectly appropriate & I was interested in your answer.

I'm sure you agree a prudent consumer should always seek validation of such claims & I'm happy you were able to offer some support for yours. After all, there are a lot of snake oil salesmen out there - Peace

Pete Lech

It would seem that the Fabspeed airbox cover, like a cove filter, would ingest water where the drilled out cover has the holes on the bottom where this would not happen. (Not that I drive in the rain on purpose, but even in California, it happens.) On my 911, I took a sabre saw to the airbox, and made a Fabspeed style retainer for the K & N filter for track use. Can't say the power was greater, but I sure loved the throaty sound.