SlightlyoffAxis

I have read many conflicting things and a lot of it makes sense so that adds to my confusion.

On one hand I understand that the stock air box will flow way more air than is needed to generate 250-300hp and it is drawing its air supply from the fender which is essentially "cold" air. The cone filter is claimed to draw more air and give higher hp on top but usually just 2-3hp on a dyno. But it is sucking air from right over the turbo not what I'd call cool air. The PO of my car has a hose running from the drivers side break duct into the air box pulling hot filthy air full of dust and debris right off the road surface. I have also read that putting on a cone filter can actually decrease performance if the vehicle is not tuned for the change. I have also read a club racer say that the only time he saw an advantage was when he was drafting another car, not something you do on the street.

I like the access gained by the removal of the air box. I like the look of the cone filter, I like that I can wash it and put it back on, I like that I can see how clean or dirty it is.

SO I put it to you enthusiasts what is your take on cone filters vs air box

snb13

Some have put a cone filter in the fender--same place the stock box draws from. It's the angle's of the ducting that are tricky.

marc abrams

Welcome to the forum. My take is to use the stock air box. Under the hood cone filter draws in hot air and any air filter that flow more air must have reduced micron capacity.

MAGK944

Not entirely true. Technology has moved on somewhat and oe manufacturers are pressured by price rather than performance. Hence we still see paper filters on new cars. There are better options out there in the aftermarket. K&N is old school but maybe still valid as like I said most oe filters nowadays are also old school paper. There are other better options once you filter (pun intended) through the hype.

As for location, I always thought the S2 airbox was in the perfect location, in front of the car as possible drawing air from a neg pressure area. You'd have to replace & relocate your intercooler and fit a maf so that the piping could easily be routed to it, but it would free up loads of space in the engine bay.

marc abrams

I don't want to get into a pissing contest over air filters here, but my N/A for a maybe 2 extra horsepower why risk the extra ring wear for a street car?

StoogeMoe

Didn't somebody do a dyno test at one time? I think the cone filter was worse than the stock air box. I think the K&N did not provide any power increase either.

MAGK944

I remember reading that post and its most likely correct. I agree that location of the intake has more of an effect that the type of filter used. On an na not so much but on a turbo a 10deg drop in intake air will produce peak hp gains of 10-15hp. I'm guessing you get that sort of temp drop between having the air drawn from inside the engine bay v from outside.

V2Rocket

While I support sticking to the factory airbox unless your 951 is running a MAF...

I run a cone filter "inside" a modified factory NA airbox (to make fit a slightly larger MAF housing) and found +3whp versus running the 100% stock NA airbox and standard NA-tune MAF kit.

Whether that was due to the MAF size change or the filter is anyone's guess, but I seriously doubt the filter sizes chosen by Porsche (even in their packaging constraints) are any real restriction until you get up there in air requirements.

Rogue_Ant did dynos with a stock paper filter, K&N drop in filter, and no filter at all when testing his NA-tune and found 0 difference between any configuration.

Jay Wellwood

Filter d/p has a negative impact on engine efficiency.

Larger particulate passed thru the air filter may have a negative impact on engine longevity.

Higher intake temperatures may have a negative impact on intercooler performance, resulting in negative overall engine performance.

Pick your poison.

Arominus

Stock airbox, cones under the hood just pull hot air anyways.

944Ross

Here's how you get the coolest air....