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Old 12-13-2011, 05:08 PM   #1
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987 v 986 Air box


Major difference in size between them, bigger is 987.

There is some modification to the muffler area of the 987 box for clearance, otherwise it bolts right up.
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Old 12-14-2011, 10:16 AM   #2
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We trimmed it back a little farther. Can you show us how you made the cover for the opening?
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Old 12-14-2011, 10:50 AM   #3
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Quote:
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We trimmed it back a little farther. Can you show us how you made the cover for the opening?
I just covered the hole with a piece of plastic and glued it on. Had visions of making a smaller muffler with the cut off part, but decided against it. I want it to make noise. With as much as I have going into this car and engine, I plan on keeping it for a long time. Not concerned about resale at this point.
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Old 12-14-2011, 11:47 AM   #4
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We glued and bolted an aluminum plate over the hole Used the typical 10/32 cap head screw and some nylocks.
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Old 12-14-2011, 06:35 PM   #5
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I appreciate the information, and photos. But, I have to ask.... and what? Bigger doesn't mean better. Have you run flow tests on the two? Is there some expected result you were hoping for, and achieved? Thanks in advance.
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Old 12-14-2011, 06:42 PM   #6
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I started with common sense

Hum.. I have a 3.4L CaymanS engine in a 986 Boxster, I wonder if I should run a CaymanS intake box? (question I asked myself)

We had a custom cone filter setup in the engine compartment, but they do not seal well to the engine lid or the chassis, and we would see intake air temps 40-50 degrees hotter after just 30minutes of running the car than we did in a stock CaymanS Cold air makes power (or at least closer to ambient)

I had been involved with CaymanS 3.8 conversions and knew the stock box seemed to work just fine with the larger GT3 throttle body on a 3.8

The stock box is too small for the 3.2..... about right for the 2.5 and 2.7 (same piston size in both engines)

When we see vaccuum at full throttle on the dyno, it means something in the intake system is too small and if the intake and the engine is stock..... it means the air box (to me)


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Old 12-14-2011, 07:41 PM   #7
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Thanks Brad. It could be common sense, with some of the follow up information not previously seen. Did that vacuum go away?
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Old 12-14-2011, 07:46 PM   #8
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It's tough online to see me smiling when I post "tongue in cheek" comments Thanks for not getting offended. It was meant in jest.

Yes, it went away and the engine air inlet temp went WAY down. Down to what we expected to see based on a stock CaymanS. GM has a division dedicated to inlet air temp on the Corvettes. After meeting a person who works in that group, and what I have seen on professionally raced Boxster's and Cayman's... I take air inlet very serious (to the point of covering the entire intake/air box/piping in the gold foil to keep the temps down. Heat kills!!!

Porsche cut the nuts off the Boxster's and Caymans. The trend for larger throttle bodies and larger headers is well founded, but you have to match it with a larger air box. So far the CaymanS airbox has proven to be *good* up to 420hp. I have not tested past that (GrandAm M97 engine in a CaymanS)

Last edited by Brad Roberts; 12-14-2011 at 07:49 PM.
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Old 12-14-2011, 11:28 PM   #9
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I keep looking at the air box on my racing car and wondering if there is not a better way to get cold air with higher volume into the engine. I was considering putting a plate on the location of the factory air box and running a tube out closer to the side of the car for the air filter - or how about relocating the air box/filer to the rear boot. That would give a straight line from the filter to the throttle body/plenum.

Then the air filter could be feed with air via a scoop on the rear trunk or even the roof?

Just an amateur thinking-out-loud, so sorry if this is all just stupid talking
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Old 12-15-2011, 05:55 AM   #10
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Brad,

Do you have any experience with running an intake duct sealed to the outside intake "scoop" running to the throttle body....insulated of course. I have seen a fellow on here who did a marvelous job. I would think intake temps would be reasonable. The air would be spending less time running around the engine compartment...like a heat exchanger.

I would certainly like to put in a Cayman S box (MY year?) but I am still not seeing how one can possibly get it in. I am not understanding the muffler cut either.

The Cayman box plus the IPD might give me enough juice to get by some older 911s on the track




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It's tough online to see me smiling when I post "tongue in cheek" comments Thanks for not getting offended. It was meant in jest.

Yes, it went away and the engine air inlet temp went WAY down. Down to what we expected to see based on a stock CaymanS. GM has a division dedicated to inlet air temp on the Corvettes. After meeting a person who works in that group, and what I have seen on professionally raced Boxster's and Cayman's... I take air inlet very serious (to the point of covering the entire intake/air box/piping in the gold foil to keep the temps down. Heat kills!!!

Porsche cut the nuts off the Boxster's and Caymans. The trend for larger throttle bodies and larger headers is well founded, but you have to match it with a larger air box. So far the CaymanS airbox has proven to be *good* up to 420hp. I have not tested past that (GrandAm M97 engine in a CaymanS)
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Old 12-15-2011, 07:15 AM   #11
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questions for Brad.

1. can the swap to a cayman airbox be done with the engine in the car?

2. where are you sourcing the cayman airbox? Model year and what price?


thanks
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Old 12-28-2011, 09:53 AM   #12
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In addition to my questions above, I was wondering if the MAF housing was the same diameter as the 986? if not, do you use the 987 MAF sensor in the 986?
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Old 12-28-2011, 10:31 AM   #13
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Reading the replies now.. didn't receive a notification that someone had posted
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Old 12-28-2011, 10:42 AM   #14
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Tommy,

you want to use the CaymanS MAF housing. It holds the same MAF your 2000 car runs.

I happened to have one close to my desk. I'll show you the CaymanS MAF holder and boot, then show you the 986 (side by side)





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Old 12-28-2011, 10:47 AM   #15
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As far as pricing goes, I expect to pay about half of new when buying these parts from places like LAPD/OK Foreign/PartsHeaven

Part number: 987.110.021.00 NEW Price from Porsche is $560.00

You will find it in cars from 2005-2008 ALL 2.7/3.2/3.4 cars.. all of them..


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Old 12-28-2011, 10:56 AM   #16
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Stock 2.5/2.7/3.2 utilize a 74mm diameter inlet at the MAF sensor.



CaymanS utilizes a 82mm opening!!!!




Just noticed the spider in the BoxsterS MAF tube.. LOL
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Old 12-28-2011, 10:59 AM   #17
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Tidbit of info: The 987 tube has a MUCH finer screen to help protect the MAF compared to the early 986 style (The 987's rarely kill a MAF like a 986 does)
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Old 12-28-2011, 11:08 AM   #18
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JayKay,

I have not seen exactly what you are explaining, but I do understand the concept and yes, anything you can do to seal the aftermarket "cone filter" setups to the outside of the car.. is GOOD!!

Muffler: Porsche has installed a resonator chamber/muffler to decrease (or control) the sound of the intake on the Boxster's/Caymans. They accomplished this by a "pimple" hanging off the intake tube, on the 2005-08 cars this "pimple" was part of the air box right where it makes its transition to the throttle body.

I'll show you with a picture..
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Old 12-28-2011, 11:09 AM   #19
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thanks for the great pics and info.

So I can just re-use the MAF from my 986S but put it in the 987 housing. Its not calibrated to the tube diameter?

Can the housing swap be done with the engine in the car?
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Old 12-28-2011, 11:24 AM   #20
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"can the housing swap be done in the car"

Yes, but you will be removing the drivers side intake plenum

"So I can just re-use the MAF from my 986S but put it in the 987 housing"

Yes. Correct.

"Its not calibrated to the tube diameter"

The MAF is not. The computer will adapt
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