I thought the 987 cayman S has a resonance flap on its intake plenum? Did you tee off the resonance flap vacuum line to run it?

I believe we left it "open" I have slept since then, and the car is in Texas.

Interesting. I've been wondering if you could run it off the resonance flap vacuum line. I wondered how it would affect intake charging if both the resonance flap and plenum flap were closed and allowed the 986 to run as two 3 liter engines.

At around 5k rpm I think the 986 resonance flap opens so if we could tee that vacuum line, it might be possible to get the extra airflow advantage at high rpm, and retain low end torque.

Not sure if this is possible... Just a thought

You are on the right track :) I believe we actually removed the flap from the pivot. I'm going through pics right now trying to jog my memory.

I have a 997 plenum, cayman S plenum, and cayman S throttle body coming soon to play around with to see what I can get.

I've looked like everywhere and this is the first I've heard if someone putting the 987 intake on a boxster m96 engine.

As I posted above.,.. :) the 2.7/3.2 intake was too small for the 2.7/3.2 :) Why does a 3.2 make 50 less hp than a 3.4 with essentially the same heads/cams?? Intake and exhaust are too small :)

We had a LOT of time into the adapters we made to adapt the plenum.

We are kinda past that at this point. I'm working on 9A1 NON DFI intake onto the larger DFI engines right now. The first 9A1 engine was NON DFI (2.9) it uses the same center section as the 3.4/3.8 DFI.

Once I get this done.. the DFI engines will go right into the early 987 chassis (and possibly the later 986)

I've already had a 2.9 running in an 06 chassis :)

Project 3.6 coming together
 

I know I'm going to need to get reducers to fit the plenum to the manifold. I've been considering getting the larger intake manifold for the 986 but if figure that the manifold won't restrict the air as much.

However, the 987 intake box will probably be the final upgrade to the intake system. To maximize airflow without need to get a larger maf housing an complete remap. I also don't want to end up in the situation where the injectors can't richen up the fuel enough.

Not really reducers.. the main issue is: bolt holes don't line up. We actually installed the 987 intake onto 3.4 heads on a 3.6 LN block. The 3.2 heads *might* have been easier, but we already had a fully prepped set of 3.4 heads sitting around/ported/flowed.

Porsche used the 987 airbox stock in the 50th anniversary 986. The "tune" comes up in the PIWIS when I perform 986 programming.

Oh, you mean the 987 intake manifold right? I'm going to stay stock with the 986 manifold for now.

Yes, sorry. The intake required adapters.

987 Box goes in, but requires you to cut the muffler off of it to clear the 986 brake lines that run on the drivers side of the 986 engine compartment.

the flapper on the 987 plenum actuates at different rpm than the resonance flapper on the manifold. if you search you can find a description of the activation points. also note when you look at the ecu pinouts that the signal for the plenum flapper comes from a different pin than the signal for the mainifold flapper, which would indicate that it's triggered at a different point.

otherwise, the boots that join the plenum to the manifold are rubber and have enough give to fit a larger plenum - no need for adaptors.

I believe I crammed a 3.4 T in place one time :) Its tights, but works.

Perfect. Didn't want the muffler anyways.

I'm sure on a 3.6 that frees up a good chunk of hp. I imagine I won't get the same percentage gain on my 2.7. I imagine I'll start seeing diminishing returns with cam timing and injector capabilities limiting the amount of usable air.

There is a big thread buried somewhere. I showed how I modified it to work in an 01 986

Nice. I think I'll go as far as I can to see what I can do on my own, then I'll go scouring the forum for some more insight.

I won't really be dynoing the process, but I have a Bluetooth obd2 scanner that gives me access to most of the PIDs, enough for it to 'calculate' hp and torque while driving. Throughout the upgrade process, I'll make a standardized test that takes me through the rpm range ( probably only 1st through 4th gear) and look for changes in the curves compared to the stock baseline. ( I think this form of dyno falls somewhere between butt dyno and a proper dyno)

ALL the 2.7 987 Boxsters use it and make good HP :)

Ive seen that the plenum flap has multiple unique activation points. My hope is that triggering it with the resonance flapper may still provide some gain though the intake tuning wasn't designed for it. Happy accident?

or restricted airflow at low rpm. porsche. never used a plenum flapper on the 911 i don't think.

Project 3.6 coming together
 

If I feed the plenum flap from the resonance flap, it should open at 3k rpm, thus not restricting airflow at low rpm. The downside is that the resonance flap closes at >5k rpm and so at high rpm I may restrict airflow since the intake manifold will be cut into two separate intakes. My hope is that this will cause a supercharging effect at the heads (crossing my fingers), or wreak havoc on the intake tuning lol.

This is the extent of what I think I know. Does it make sense at all?