987 v 986 Air box

[DenverSteve]

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.

[Brad Roberts]

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)


B

[MileHighBoxster]

Thanks Brad. It could be common sense, with some of the follow up information not previously seen. Did that vacuum go away?

[Brad Roberts]

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)

[jaykay]

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

Originally Posted by Brad Roberts

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)

[tommy986]

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

[tommy986]

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?