Air flow kits

Does anyone feel a air flow kit is worth it for a 996 c2

What is an air flow kit? If you're talking about after market airboxes and air filters. then it can be a good thing. But only if you get something that has a pod filter with some sort of box around it. they are the ones that'll yield in an upgrade. You only want something that'll actually bring in cold air though.

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The first attempted upgrade for my 996 was a K&N Air Filter.  It was fitted as per their instructions.  It slightly increased induction noise, and in my opinion gave no power increase at all.  What it did do, is completely foul the MAF sensor and stuff it.  I thought I would be smart and buy a cheap MAF sensor, it worked for about 10 seconds before it also became oil fouled and stopped working.  I took the K&N filter off and threw it to the shizenhousen!!  IMHO stay away from any oil drenched pods. The MAF on the 996 is to close.  I have an exhaust upgrade now, I am not sure it gives any extra horse power either, but shit it sounds good. Cheers Steve

From what I've read on rennlist, I would stay away from after market air filter kits. People have reported similar experiences to what Steve mentioned above through to a non running car with about 2 or 3 owners claiming that the result was so bad it has forced them to do an engine rebuild. Most of them however just say it runs lumpy and likes to stall so if that's your kind of thing then go ahead with it. Otherwise if you're talking about brake air ducts/spoilers then it's relatively cheap with little harm and can help keep your brakes a little cooler if you're a heavy user (ie. tracking the car)

I should note. Any oiled air filter isn't good for MAFS. unless its a hitachi style that the maf wire isn't exposed

I have the EuroCup GT twin intake carbon fibre y pipe http://www.porscheshop.co.uk/acatalog/porsche_996_engine_induction.html In my research that seemed to be reasonably favorably reviewed.  Having said that there is considerable debate about whether they really do anything other than help to make the sound a bit meatier In my opinion it does nothing for performance but it does add some nice induction noise to the soundtrack which combined with a sports exhaust gives the car a very nice sound which is much more '911 like' than your typical 996 Carrera.  Because it is exposed unlike the standard box which is enclosed there is a slightly increased risk of water getting in if you drive through a large number of puddles but to be honest that risk is relatively minor in my view. In terms of bang for your buck I think it is questionable and there are a number of other things I would do before this. If you want to do brake ducts, the brake ducts from the 997 GT3 are a straight fit and should provide slightly better cooling, every little bit helps if you wish to track and for around $25 this is a no brainer

As Mike mentioned this has been heavily debated on rennlist and all the other forums. I researched extensively after buying a BMC filter (buy first ask questions later!) what I found was much similar to what everyone has said on here. - K&N will foul the MAF so will the BMC if over oiled or oiled incorrectly, if you want to go down this route leave them on a towel to absorb some of the oil (this is no guarantee though) - Cotton/non paper filters can filtrate better than paper but only when paper begins to get clogged (i.e when the paper becomes clogged at the same point the cotton will keep filtrating) IMO a filter should be used, thrown out and replaced not reused. - On the dyno there were power increases at the very upper HP range, down low there was no power increase (as stated in other forums). - Cotton is reusable but requires skill to get clean and operating correctly i.e. again not to foul your MAF From personal experience the BMC filter made my car less responsive so I pulled it out. As for the intake system from what I have read the original air box setup is said to be the best one. If you want an altered intake sound remove your Helmholtz resonator box inside your air box plug it up and get a straight intake pipe (like the Fabspeed CAI intake) not the competition one though thats 2 pod filters that suck in hot air from your engine bay.

Thanks for the details on your experience Dan. Would be nice if there was something out there that just worked though.

Does the 996 have the horn/noise reduction thingamajig. The 986 does, right at the air intake point. Remove that for induction noise. Noice

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There is,it`s made by Porsche, and your car came with it from the factory.

I meant for a louder sound on a C2 and a bit more power Porsche only offer a full GT3 option for that if you can afford it

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Yes it does. All C2/C4S have it. As mike mentioned the turbo, gt3 and gt2 dont have it. It is called a helmholtz resonator. It's a box that's size is calculated to eliminate certain sound frequencies above a certain rpm range. It can be safely removed but the hole it creates must be capped off. Americans call it the orange cap mod. Where basically they found an orange cap that was exactly the right size to block the hole. I removed mine it sounded great. Especially with my cargraphic exhaust would create a great burble as the revs dropped! The intake noise itself wasn't great but the other sounds it would conjure the exhaust to produce were great. Hit me up if you need more details!

More info Dan. Never heard of this mod before. Was it liveable? Produce much drone? What was wrong with the intake noise?

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Sure no problem. Applicable vehicles: all 996 models of all years excluding: GT3, GT2 and Turbo Inside the top section of the air box there is a small box/sealed chamber inside it. The neck of this box is connected to the rubber intake hose to the throttle the rubber Y one end goes to the throttle the other two ends go into the air box. The reason for this is the scientific principle of a Helmholtz resonator. The chamber when connected to the box cancels out certain intake noise frequencies to reduce noise emissions. This is said to be because of requirements to meet Swiss noise emissions. The science aside, when you remove this box/chamber and use a straight pipe without the Y (i.e. one that goes from the big airbox intake to the throttle you eliminate the resonance effect and get... More intake noise! Widely debated and proven to only add intake noise and no performance. Removing it is harmless! So to remove it there are 3 ways: 1. Get a straight rubber silicone hose from the airbox to the throttle can be bought on ebay from anywhere between $70-$250 2. Seal up the hole and continue to use the standard hose. What the Americans discovered is that there is a particular sized plastic orange cap that seals up this chamber which sits on top of the neck and is held in place by the rubber hose. Thats where the modification got the nickname "orange cap mod". 3. Buy a schnell or Fabspeed CAI kit. Personally I was able to purchase an additional chamber to modify and seal up keeping it all looking factory and having proper reliability because you dont want anything sucked into your throttle because you're past the air box's large screening filter! The 997S actually has a vacuum operated flap inside the air box that closes and opens to allow more intake noise at higher RPMs!

Also to add as a suggestion - you could get a couple of black pvc plumbing pieces from bunnings and plug the hole (screw down and cap). My cars a tip so I put a mini breather filter on the end of the tip breather. Removed the resonator and with a back Silicone pipe from ebay and all was done for about $60. Below is example - not my car.

Castrol oil bottle cap is a perfect fit. Cheapest mod ever, given I use Castrol oil. Remember to remove the plastic thingy from inside the cap then just slide it into the hole. The lip of the cap stops it going in too far. Then re-attach the hose which also holds it in place. Enjoy a little bit of extra noise but only above 4,000rpm. IMG_3814 by Simon Kovac , on Flickr

I went one step further and was able to find a complete top of an air box, removed the chamber, cut it in half and glued a base into it. I didnt want to risk having anything foreign flying into the throttle or plastic potentially degrading from heat and unfiltered bits of plastic getting sucked in

Theres also the famous Gundo Hack, by welding thus diverting around 50% of exhaust so more goes straight out the pipe, this is said to give the best sound

Has anyone on here done the Gundo Hack? If so, whats it like? Where can you get it done? Simple exhaust shop?

I opted for the Fabspeeds. However, if you want more noise than now (like having factory sports exhaust always on) this is a cheap alternative. Yes, any exhaust shop can do this. Easy to look fo rpics to take into them to explain what you need.

That kit with the red silicon intake tube that dan_189 posted pictures of above was on my car along with a K&N filter when I got it.  It was pointed out to me that the idle on mine wasn't as smooth as it should of been so that then started to niggle at me.  I tried a paper filter, cleaning the MAF, a new MAF sensor (believing the the filter oil had buggered the old one).  In hindsight I should have done this first, but in the end I dug out the original tube and air box thingy and put it back on.  It now idles as it should and low throttle openings are a lot smoother to boot.  I'll admit it probably sounded better before but I'm not inclined to go back to it.

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Out of curiosity, with the red tube installed did you have the resonator box in place or was that removed and there was a hole in the top of the airbox?

The hole was blocked with that carbon looking plug.

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Did the carbon looking plug have a rubber ring around the neck?

Can't recall to be honest.  It would definitely have been sealed though.

Without the rubber ring from the original resonator box the fabspeed block off actually doesn't seal the hole it leaves a tiny gap. That gap causes the issues you described. The fabspeed instructions don't call out to actually use it to seal the hole but it's needed or you get an airbox leak that I'd be willing to bet caused those problems.

Interesting,  I'll have a squiz when I get home.

Here's the pic I was looking for, notice how the Fabspeed block off doesn't quite seal the hole without the rubber O ring.