Tahoe M3

Has anyone successfully removed the restrictor plate on the 987? I saw the instructions on Cayman Club but I wasnt able to get the side grill off. Any tips on getting this thing off without scratching the paint or breaking the grill? Also, any dyno-proven gains? On the Cayman it was good for 13 rwhp, and I'd expect the same given how restricted the intract path is. Thanks.

arenared

The instructions are over on RennTech. I seriously doubt the 13 HP gain other than being statistical aberrations.

Tahoe M3

I think it's very possible...have you seen how narrow the air intake space is? There's a gap of about a finger-width that allows air in. If you remove the restrictor plate, the intake area will increase by a huge amount.

Mabuhay

Why is the restrictor plate there to begin with?

Jim Michaels

Porsche calls the plate an air deflector. According to the Service Information booklet for the Cayman S (page 2.10):

"The engine intake air is forced to flow around a deflecting distance plate, as a result of which water and particles are largely drawn off via the water drain at the bottom. This air routing results in a marked improvement in the level of water separation up-line of the air cleaner (when driving on surfaces which throw up a lot of spray), thereby protecting the hot-film air flow sensor from failures resulting from the intake of ultra-fine water droplets."

Tahoe M3

Supposedly it also had to do with an incident where a cigarette got sucked up into the intake and lit the air filter on fire.

It seems like the chances of this happening are quite small. There is probably more risk of air-senson damage. I would think they could strike a better balance...have you looked to see how small the space is for air flow??

Jim Michaels

Tahoe: Do you mean by "air intake space" the narrow gap between the air deflector and the deflector distance plate? If so, how much more space would you guess is needed between them? Behind the air deflector plate is an even smaller entry into the air guide that goes to the air filter housing. That small entry seems to be about the same size as the air entries in my previous 911s. Thus, I don't think that air intake will "increase by a huge amount" if the deflector plate is removed. I suspect that air intake is sufficient with the air deflector in place.

I'm aware that Ken reported getting an additional 13 rwhp on his Cayman with the deflector plate removed. I'm also aware that Scott Slauson (PCA Boxster/Cayman tech specialist) reported getting the same hp on Caymans with and without the plate, and on both the OE 3.4 engine and a 3.8 transplant engine. I'd love to believe that 13 rwhp would be that easy to get.

Tahoe M3

Jim,

Yes, I think we're talking about the same thing. I haven't been able to get the outer trim piece "grill" off yet, so I can't see what exactly is inside. There's a DIY on caymanclub.net that shows the procedure...one pic indicates how narrow the space is around the restictor plate.

While I haven't seen the underlying air intake port (what you refer to as the "smaller entry into the air guide that goes to the air filter housing"), I would assume that removing what is essentially a baffle would allow air to pass into it much easier from the side vent. This would effectively increase the area of the air collection from the side intake from a narrow finger-width space to the full area of the side vent. Instead of bouncing off a restrictor plate, the air would be funnelled directly into the small intake tube which would increase the velocity and essentially pressurize it over atmospheric pressure...better breathing and more horsepower.

If the assumptions above are true as far as the design of the intake tubing, then I don't think 13rwhp seems far-fetched. Anyway, whatever the case...I'm still stuck on step 1.

Jim Michaels

If I recall correctly, the caymanclub DIY photos show/tell how use a screwdriver to get the clips behind the grill to release the grill. I don't think the grill will pull out without first releasing the clips behind it. I think they said that the clip part was the hardest part, and suggested starting with the clip on the upper right, then move to the one on the left, and finally to the lowest one. If you already knew all that, I can't be of help. 13 extra hp so close, yet so far away.

Tahoe M3

Yup...it's such a tease. I tried starting on the one in the upper right, but unfortunately you can only pry the thing out so much to access the clip...it's a really tight space and seeing in there is tough even with a penlight. I think I need a smaller screwdriver to squeeze in there...I'll post an update if I get it to work.

mbodo

.. please post that update with pics .. The one on renntech doesn't seen very intuitive, or I'm just afraid of breaking fragile little plastic vents.

Jim Michaels

There's an clarifying update with photos under the mods forum at caymanclub.net. The hang-up seems to be bending the outside grill enough to get to it's releases without breaking it.

Tahoe M3

OK it's done. The problem ultimately was that I didnt have the right tools. With two small flat-head screwdrivers I was able to get the first clip apart, and then the rest was easy. The restrictor plate is huge and very..of course...restrictive. With it in, there's almost no space for air to get to the engine. With it out, there's a straight shot to the large air intake port.

Driving impressions? I can definitely tell a difference. The car feels quicker in normal driving and the intake sound is louder...makes it even more fun to drive around town. Pushing it on freeway on-ramps, etc, the car is noticeably faster especially above 5000 rpms where there's a nice push in the back that wasn't there before. I can believe the claimed 13rwhp gains posted on cayman club...that would equate to a 15+ hp bump at the crankshaft.

I can post some before and after pics if it will help.

Chris C.

Hmmm. 15hp!?

There is tech letter/article in this month's Excellence (might be Pano??) talking about this mod. Apparently F-L and others have tested 987 cars and found that the factory setup is excellent...in other words no gains were achieved by removing the restrictor.

Tahoe M3

I have no dyno numbers, only seat-of-the-pants impression. The Cayman guys did dyno 13rwhp for this mod, so I don't see we wouldn't get a proportionally similar increase. The restrictor plate really limits how much air can get into the engine.