Otto Mechanic

I'm new to the 944S2 (from a user's perspective, I've owned one for 3 years, never used it) and I'm looking for advice on the maintainability of the stock air filter. When I bought the car I just put an air filter on the list of things to change and now I find out that it's been cleverly hidden behind several body parts and it takes a bit more than 5 minutes to change.

So I'm thinking to myself "Self? what about a cone filter that might be easier to change?"

I understand the forced induction (Ram) on the stock air box might be a real advantage not worth messing with and I'd like opinions on that subject. Could a cone filter be fitted to the S2 in a way that makes it easier to maintain without compromising flow? Is there any hard (dyno) data available? Does it even fit?

I'm willing to put up with an extra 45 minutes of bodywork every month or so if there's a real advantage to the stock design, so I'm looking for experience. This isn't a street car so it will occasionally suffer from off road excursions that will make replacing the filter essential.

Thanks for any advice,

V2Rocket

Seen a few S2s set up that way, unaware of any dyno evidence one way or another.
I think the S2 got it under the nose panel because it fit there rather than it behind an optimal spot (since the S2 intake manifold sticks a lot further forward into where the 944S airbox would have otherwise been)

Nice thing about the stock S2 filter is that it's SO BIG you'd think it might have a longer required-change interval. Does it really take that long to pull off every 12-18 months?

I haven't messed with a stock S2 front end in a long time but isn't it just 1 sheet metal screw into each fender, 4 across the top by the hood latch, and 1-2 nuts per side under the headlights? Since my car is all custom under the stock S2 skin mine is different, I just have the two fender screws and 2 more screws holding the top of the panel to the latch...tested fine up to 130+ mph

If you did decide to pursue this and if it were the right size I might be interested in taking the stock S2 airbox off your hands.

Otto Mechanic

Spencer, I have no agenda really, just asking questions and you seem to betray an ulterior motive by sort of indirectly asking if I might give you my stock air box cheap? I think I'll take that as an answer...

PaulD_944S2

Scott, I have an S2 (you knew that) and I clean the filter every 15-20K and change it when I do the belts. Surprisingly, the filter stays pretty clean, it's mostly dust (few leaf parts, stems) on the inlet side. I don't think I have seen an interval in the Porsche service manuals, but I could take another look.

I think the filter is a great piece of engineering, and better than any cone filter could ever hope to be, and with its huge surface area I doubt if there is any drop in flow (my opinion, comes from putting things in parallel if you get the logic), and while its not in the most convenient place, it is a good place for it. Once you have changed it, it's not a bad job to do, about a leisure hour.


BTW, I think the intake filter is in an optimal spot. The area behind the fascia is a high pressure area, that's why cooling systems are in there!

PaulD_944S2

One more thing, cover the top of the fascia with tape and thin cardboard because when you slide the header panel forward you don't want to scuff the paint. Sometimes the header panel is a little sticky or hard to pull forward if its been there for a long time.

Good luck!

V2Rocket

just another ramble of mine turned into a WTB post...lol

Otto Mechanic

Thanks Paul. Between you and Spencer's back handed compliment of the system, I think I may have made up my mind?

Best Regards,

Otto Mechanic

Aha! But I see your solution still requires body work to clean or replace the filter?

Regards,

Dan Shea

I'm in the middle of this process albeit for different reasons. I had a cone and stock AFM before due to not getting the S2 air box with my s2 motor (did a motor swap years ago). Now I'm switching to a Link ECU so I'm doing a map sensor instead of the AFM. With the Map, I bought a 3" universal intercooler kit off ebay that came with some silicon connectors. I run a pipe with 45* bend out of the throttle body, 5lb sledge hammer to massage the 3" pipe to fit between the hood and headlight bar, the 45* bend takes it right down into the header panel, 90* silicon elbow in the header, short 3" pipe to the air filter. We haven't finished the ecu install yet, so I can't speak to gains/losses, but I didn't have much of a choice.

If I were to do it again, I would only get 1 45* pipe and the 90* elbow to save some money. I knew I was going to do some 'engineering' to get it to work so I purchased a little more
pipe/elbows than I needed.

jhowell371

Seems the S2 air box is quite clever in design, anticipating some neglect due to it's placement. My understanding is only 1/2 of the large filter is used at one time. When one side clogs to the point of restriction a flapper responds and directs airflow to the cleaner side. Mine is missing the flapper, sacrificed no doubt to a PO who was looking for a bit more performance by allowing air thru the whole filter. I put a "high flow" aftermarket air cleaner element in my S2 but took it out and returned to stock Porsche element. I couldn't tell any difference and felt the stock element provided better protection. I have seen a cone setup on EBAY for the S2 but it's still behind the header panel. Your mileage may vary.

V2Rocket

the setup pictured was from azbanks' car, IIRC, not mine.

all this time and i haven't put it together that you want to move the filter out from under the nose, to somewhere inside the engine bay...

the problem again comes down to the AFM being in the way...you'd have to get an elbow to turn the AFM towards the driver side headlight (or the other direction) to be able to fit a filter there.

Otto Mechanic

Yeah, that was really the question, whether anyone had made something like that fit at all, and what the consequences might be. I was sort of eyeballing the space between the headlight and the coolant tank but it didn't look too promising.

So far it sounds like folks are pretty happy with the S2 air box and don't have any real concerns about taking the nose apart to service it. I'm used to the 928 air box, it takes about 5 minutes to change the filter in one of those so I'm spoiled.

Otto Mechanic

Thanks Dan, this sounds like another testament to putting the filter in the nose one way or another. I sort of also read between the lines that you'd rather have the stock air box?

I think we're now at 4 out of 4 S2 operators voting in favor of the stock air box...

Regards,

Scott at Team Harco

Every month or so? I check mine every year or two (whether it needs it or not). I use a K&N and have only needed to clean it once in the eight years I've been driving it.

As already stated, the design is good. The inconvenient access is a minor detail. I'd look for other areas to "fix"...

Otto Mechanic

I'm a natural pessimist Scott, what can I say? When I mentioned I'd be tracking the car, and anticipated the occasional "off road excursion" I was really talking about my own unfamiliarity with the car, not a problem with the air box design

I just figure I might end up in the weeds a few times while I'm learning to control the beast...