I've read so much about this that I just can't get an oppinion...

I know that a filter reduces the ability of the engine to "breath air" and, on a performance one that hopefully pulls more air into it, the probability of it restricting the air flow exists.

But what happens in our cosworths?

The pannel filter has a significant area and, acording to what i've heard, on a cossie airbox, a decent K&N panel filter should do the trick for a big HP engine.

I've had a K&N for 7 years now and never thought of changing it, I eventually clean it from time to time on the dish washer when the missys not at home , but am i better of leaving it alone? or should i get a benefit from changing it?

Don't get me wrong... I'm not a noob. I know there is much more than just air flow like angles, turbulence, etc... But what do the experts say? is it worth the money?

I'm on greens with about 340bhp

 

You clean it in the dishwasher?

 

Dishwasher

It'll shrink the cotton filter material which will make the filter useless. You need to use the proper cleaning solution and let it air dry.

 

No point in changing at your power.

 

Oops... I thought it was like clothes and only shrunk if it used hot water. I only use the final washing program.

 

They are rather delicate, and can be damaged by too much water pressure blowing a hole through them.

 

In the majority of cases on most cars,they cause more harm than good than good, the oil gets injested and cloggs MAF sensors, and you can suffer heat soak so you are worse off than if you left the standard filter in the 1st place!

A panel filter is best imo if you want to upgrade but it really does depend on the car, for example some cars have snorkels, so the OE setup can be pretty decent!

Martin

 

The K&N panel filter will work fine at your power level, just clean it with the correct K&N cleaning fluid and re-oil with their oil. Some people use a starett hole saw and drill holes in the intake side of the air box to help get more air in, can't see why this shouldn't help tbh.

 

the oil and cleaner is about Ł20, so still cheaper to just keep the standard filter or use an aftermarket paper filter

it's all about filtration vs air flow, with no filter there is no blockage, but you can pick up dirt and shit

and when you clean them, you need to wash them in the cleaner gently by letting it run through, not leave it to get battered in the washing machine

 

They do flow air better than the OE filter, I fitted a K&N panel filter to my diesel Focus and the increase in torques is superb

 

There used to be a k&n thing in demon tweeks, a fan set up with ping pong balls with a std air filter and a k&n panel filter, and you swapped filters to see the difference in height the ball was being blown up a tube.
The difference was fairly impressive with the K&N in

 

I tryed a green panel filter in my focus tdci. Didnt feel any difference in power whatsoever. Ended up with a fooked maf within a few month tho so after forking out 130 pounds for a new maff. Lesson learned

 

iv been using k&n with good results with a cone filter that is but i think i prefurr the cone more for the induction noise than the 1-7 bhp they are supposed to give you

 

Can beat induction noise.Ive got a cold air feed pipe coming from the front of the bumper to my cone filter.

 

I'm buying a Focus 1.6 Ghia with 36k on the clock and I'm thinking of replacing the standard panal filter with a K&N. I'm more interested in economy rather than any slight power increase and I just wondered if any of you guys and gals who have replaced the standard filter have seen an increase in MPG?

 

I don't think you'll see increase in MPG. The filter has less resistance than the stock filter, but when you are on part throttle the throttle itself gives the resistance to the air flow. So whether it's the filter or the throttle lowering the air flow wouldn't matter in my opinion, it should give the same MPG.

 

That's what air flow sensors are installed for

 

The other good thing bout keeping a cossie air box and k&n is its sealed so you get heat soak from the turbo. Mine came with a group a filter so kept it but would have just got a panel filter and cut holes in the box if it came with one!!

 

I have the bottom half of the airbox with the ducting but have fitted my k+n cone filter inside it

 

Yep, seen that at Autosport show!

 

Though this air filter thing is an endless debate, I still tell my opinion. I have Pipercross cone filter which should be good. Atleast certain engine mapping specialist told me that it is one of the best air filters you can get. It was in my car when I bought it so I let it stay, it also makes awesome induction noise.

However if I would have the original box in the car I would put K&N panel in it and drill some holes in the box to increase airflow, and perhaps some kind of induction pipe. Airbox protects the filter better from heat of the turbo (should not be an issue, atleast in high speeds because of airflow), but cone filter should have bigger surface area.

Either way, I think that any aftermarket filter, whether it is cone or panel, will do the job. Difference beetween them is at best probably couple bhp which has very little meaning in turbocharged car where you can gain more hp with other modifications...

 

I remember a few years ago in performance ford they done a back to back filter test on rst's and a drilled air box gained roughly (cant remember exact figures) 7bhp but lost 2lb/ft with a k+n panel filter. The standard airbox and k+n gained less bhp but torque improved