Correction to the below statements. Please read in full- I put a new K&N filter on my car yesterday and it felt the same. However, i decided to revisit the deflector plate again. When the body grille is installed over the plate, I agree that it does appear to be very restrictive. So, i removed the restrictor plate again and took a peak down through the tube/snorkel. With the plastic support bracket in place on the filter, the paper or cloth portion of the element is not exposed. So, water would have to pass through the grille, into and down the air duct, make a 90 degree turn, and then make its way through the filter and up the tube to the mass air flow filter. The next time it rains i am going to go for a drive and see how much water accumulates in this area. If it is significant, then i will modify the plastic deflector plate to allow more air to enter. Anyway, i took the car for a ride and it runs smoother, has harder acceleration, and appears to be getting better gas mileage. I guess the plate really does restrict a good amount of air flow. I plan to do some dyno results to see. I need a baseline before i add the fabspeed headers anyway. So, that is my update. Sorry to flip flop!


So i googled Cayman S upgrades and found a thousand posts on the water deflector shield, or as some call it, the Air Restrictor Plate. Some people claim to have gained 13rwhp by removing it. No doubt this restrictor plate was designed by Porsche as some devious plot to keep the hp of the cayman lower than the upper models, right? hmmm, ok. So, i figured while i was tinkering around with the air filter, why not check out this "restrictor plate"
My opinions, and remember, they are just that.

-It's not a restrictor plate, it's a deflector shield for road debris and judging by the design of it, mostly water. There is no way that I would leave this plate off under any circumstances. The air filter connects just a few inches away from the shield and then there is a tube that leads to the engine. This tube houses the Mass Air Flow Sensor. Guess what happens when this sensor gets wet??? It fries or shorts out and your car breaks down. If you have a K and N air filter i suggest going light on the oil when refreshing/recharging it. The same thing can happen if you over oil the filter.

-I don't believe that the engine can pick up 13 hp at the wheels from removing this plate. Would i believe 1 or 2hp, sure, maybe. The front and top of the plate create a seal with the housing to prevent water from getting to the filter. HOWEVER, the underside and back have enough room to fit my fingers underneath and all the way around with ease. In my opinion there is more than enough room for this engine to draw in the air that it needs. Porsche would have designed the intake system far different if it was really restricting the breathing ability of the engine.
Pictures

Deflector plate-i will no longer refer to it as restrictor.


Deflector plate again-showing the drip rail on the rear portion.



Deflector plate removed



Deflector plate removed and vent reinstalled. Now you can see why it is a horrible idea to run the car without the plate. Tons of water can find its way directly into the filter.

 

i'm with you on this one... ive seen a bit about this mod on the forums.
of course most of the cars i have owned there has been some 'baffle, or hose' that people remove to gain more HP.... there was on my jeep, my mustang, my bmw, etc.. i think it's just wishful thinking.

i have always been skeptical. i have no doubt that it likely add some deeper sound to the experience... but 13hp... come on. and, i'm with you, looks like there is the potential for water to sneak in under the right circumstances... not a risk that is worth taking IMO.

 

What you are referring to is called desnorking. There are no real HP gains to be had by preforming this change.

Here are a couple articles on it from Planet 9

http://www.planet-9.com/reviews/boxs...xample-29.html

http://www.planet-9.com/reviews/caym...xample-29.html

 

Driver8- I agree and that it why i put the deflector/water shield back on immediately after I explored. Due to all of the buzz, i felt i had to check it out for myself. I wonder how many people have trashed their paint trying to get the grille off?

Atob-You got it man! My first car was a 94 blazer and i remember reading about how if you flipped the air cleaner lid upside down the SUV would gain 5 horsepower. Not sure about that, but it did make more noise. It became annoying after about a week and i could tell the filter was getting extremely dirty, so i decided to reverse the lid. Just like you said, on every car i have ever owned there has been some quick fix to gain hp or gas mileage. I can see why some may think that this would provide quick and easy hp, but I definitely do not and the risk of running the car without the deflector/ water shield for minor benefits are too high. A new MAF will run around 500.00, not to mention the tow.

 

You would be surprised at the amount of cigarettes you would find in early boxster air filter boxes.. I know of more than one instance where it caused a fire. Screens showed up next model year.

 

I found this in the front yesterday. I will be adding the mesh grilles in the near future. Any brand recommendations??