mike9186

I bought and installed the K&N 57-7000 CAI kit a few months ago and have put 600-700 miles on it. I've been very happy with the sound it produces and I do notice an improvement in throttle response and power. It just seems to wake up the car and encourages sporty driving. Also Sport mode feels much sportier and I drive in sport mode pretty much all the time now. Also I've been using an AEM dry filter because I've heard the oil in the K&N can foul the MAF (the K&N that came with the kit seems very dry however)

Yesterday I had some free time so I decided to reinstall the stock airbox with a brand new filter I picked up on Amazon. After going for a drive I noticed the car seemed sluggish and slow to rev and just not as much fun to drive. Sport Mode felt like normal mode with the stock airbox installed. Overall it just felt less sporty. The K&N CAI went back in this morning and all the benefits that come along with it returned. The stock airbox has new been permanently retired.

Now I'm not evangelizing the K&N product specifically but I now believe that these cars do respond positively and benefit from intake modifications. I went K&N because I'm cheap and this is the cheapest intake you can buy at roughly $300 for the kit. Plus I got a lot of great information about it from Bill over at the 997 forum on 6Speedonline.

For people that say all the aftermarket intake does is suck in hot air I think that the shielding combined with air blowing over the car when moving does a good enough job getting cool air into the engine. My old 964's stock intake snorkel was positioned higher and deeper in the engine bay so that should theoretically suck in even more hot air, but it doesn't. Also people worried about water ingress through the filter, as long as you keep the engine lid closed when it is wet (rain or a wash) very little water will land on the filter element. Open the lid when it is wet and water is almost directed straight toward the filter (Ask me how I know).

Philster

There's no way in heck anyone can feel any performance gain from an intake (FTR, I have Evolution Motor Sports intake).

Sound? An enhanced roar above say 4500 RPM? Sure.

Feel it?

A dyno with computers can barely detect it.

Just like bad eyesight, it's all in your head.

.

mike9186

I also have a Cargraphic exhaust installed. Probably should've mentioned that in the original post.

That's what I thought too and I wasn't expecting to discover as much of a difference in driving enjoyment as I did. I enjoy the car much more with the CAI installed vs. stock. YMMV but I am just sharing my experience.

Fined

I wonder how much hp change would be required to actually detect a difference (without instruments) in one of these cars. I'd guess 20hp. for a 350hp car 5% is 17.5hp. I'd bet you could detect a 5% increase in power, whether any intake can get you that is another question. If ya like it and for only that much money then great!

otuA

Depends on how the increase is reflected throughout the rev range. You'd definitely feel a 15hp increase below 3.5k rpms, even if the peak hp increase is trivial.

Petza914

I feel the same throttle response change with my Fabspeed intake and wouldn't be able to feel a slight HP increase starting at around 450. I added a full Fabspeed exhaust and the better breathing in and out can be felt - the noises only add to the experience.

OP, if you want to finish the job, install an IPD plenum.

RaidersR1

Boy this air intake mod has been beaten to death.

1) "Cold" Air Intake - NO. Hot Air Intake

2) HP Gain - NO.

3) Sound - Yes they do sound good at higher RPM

I've been there and done that. Had Fabspeed on my 4S. I felt a loss on the low end. The filter is positioned to be near the intake of the deck lid. There is no way this or any HAI can change the characteristics of a car that has been developed over the last 5 decades by very experienced engineers. No way Fabspeed or K&N know more than Porsche, Period.

For California none of these manufactures are CARB rated so they cannot legally be installed to pass smog. No way is it worth the effort or the money.

Everyone is free to do what they want. Just don't fool yourself with performance gains. They are not there.

Fined

I tend to agree with the above, but at the same time.. just for the sake of argument lets say the IAT is a couple degrees more on one of these aftermarket intakes.. if the amount of airflow is greater can't that outweigh the disadvantage of those couple degrees?

I'm not advocating for it, as my 997 GTS already has a factory upgraded intake, and I don't intend to make changes there. Just discussing.

semicycler

Hot air vs. cold air is a real power killer. Let's just ignore that for a second for a thought exercise.

Porsche is known to hold back performance on their lower models by restricting airflow. The OEM X51 power kit adds a larger airbox, TB, intake plenum, and polished ports on the intake side. On the exhaust side it's headers. And then there's a tune to take full advantage of these airflow changes. There are dyno results showing if you add aftermarket high flow cats to this setup it will add power beyond the stock X51 option too. Granted this setup does not add a lot of power but it's there (maybe +25hp on good day?). So opening up the intake and exhaust along with a tune gains power on the NA 997, across the entire curve. These are facts. It's proven that changing the airflow changes the power curve on our cars. Sometimes power is added (area under the curve increases). Sometimes power is lost (area under the curve decreases, muffler delete is an example from loss of backpressure). And sometimes power stays the same but the characteristics change (the area under the curve is the same but the slopes and peaks move around, gaining or losing power at one RPM range at the expensive of another).

CAI's add sound, no debate. A CAI sucking in hot air is a poorly designed CAI (I like the HAI name here). Most aftermarket intakes do not provide more cold air than stock. Some do though, those that ram the air into the TB from the outside. But personally I would not dismiss an aftermarket intake simply because it's marketed as a CAI correctly or incorrectly. It's quite possible that an intake taking in a mixture of fresh air and engine bay air can still flow better than stock and affect the power curve where it's felt, even if there is no peak power gained, just move around. It's more likely about airflow volume than hot vs. cold air.

And just because Porsche designed the stock airbox doesn't make it the best one possible either. These same engineers designed an engine prone to bore scoring too. Or earlier models with IMS bearing issues. They also had design requirements for cost, quality and performance serving a very large consumer market. There's even a sound requirement, so they built in a Helmholtz resonator (the vacuum controlled flap inside the stock airbox that opens/closes based on engine RPM). It's very likely that an aftermarket intake can flow more air than stock simply because of less design requirements which leads to less airflow restrictions (shorter paths, better filters, louder sound). And airflow changes are proven to have an affect on the power curve - more, less, or moved around. Not saying a CAI adds power. Just saying a higher flowing airbox affects the power curve on the NA 997. And in some cases there is a positive effect that can be felt at certain RPM ranges.

TL;DR: Airflow changes affect power on the NA 997. Agreed Porsche's CAI is cold. Disagree that all aftermarket airboxes suck because only Porsche can design one.

mike9186

The K&N intake comes with a CARB sticker.

Sorry your experience was different than mine.

cutlass476

For the record the only after market intake that will improve performance is the Werks 1 composite carbon fiber airbox with WTG air filters. Why? Because it is a reverse engineered version of the Porsche X51 airbox with even better air filters and it continues to the use the stock fresh air inlets in the rear deck so you're not sucking hot engine air into the intake. Will it do much without a custom tune and an improved exhaust...probably not much. Which is why Champion Motorsports sells it in a power kit, much like the X51 package. GIAC custom tune, Tubi SS Race Exhaust, and the Werks1 carbon fiber airbox. It is basically the Carrera S X51 package without the revised heads and camshafts.

RaidersR1

I didn't know it came with a CARB sticker. A sticker is a sticker. I just find it hard to believe it's better than stock. But I may be willing to try the K&N for my car IF it really is CARB certified.

I cannot get a K&N kit for my F250!! Not Legal here. Just makes me think twice if I can have this for my car. I know Fabspeed is a no no.

I use a K&N filter in my stock box but got away from the HAI.

AltVelo

funny timing.. I was looking into this after I came across this on 6 speed.

http://www.6speedonline.com/forums/9...ml#post4466361

mike9186

From the K&N Website http://www.knfilters.com/search/prod...x?prod=57-7000
CARB EO Number D-269-34
Street Legal In All US States Yes

I was skeptical as well which is why I started this thread.

AltVelo

I'm reading the same things you are.. a lot of skeptics including me but based on those who actually bought one, they do notice gains. See the 6 speed thread, qikqbn's.