987 v 986 Air box

[Frank A]

I have been following this post for a while now and it is a very tempting mod. I have a 2000 boxster S 6 speed and was hoping to get some direction from those of you who have done this. I recently acquired a 2007 cayman S diverter T and throttle body and would like to build from there. I have a few questions perhaps some of you could shed lite on.

1- What do I use for a vacuum signal for the flap in the T
2- do I continue sourcing the rest of the 2007 cayman S intake, MAF, and air box
3-From what I gather from the post, I use the maf sensor from my old setup installed in the cayman s MAF tube and my DME will adapt, if not will the X-51 flash help.

Thanks for your knowlege and advice
Frank

[The Radium King]

1. i *think* you should be able to take the vacuum signal that drives the resonance flap on your intake and use it. if you look at your intake there are two tubes that join the two sides together - the diverter 't' and the resonance tube. on the resonance tube there is a vacuum-driven flapper valve. 't' off this vacuum signal to drive the flapper on your diverter.

2. personally, i would just connect the new diverter/throttle body to your existing airbox/maf housing to start. this way your car can work with it's original tune and you can see if you get any performance improvements, if the flapper in your diverter is working, etc.

3. if you do go to the cayman airbox, you can saw-off the maf housing on your original airbox and plumb it into the system, or you can use the cayman maf housing and see if your ecu will adapt, or you can push a 996 tune onto your car (designed for the larger maf housing). only the first is certain to work; i've not heard with any certainty that the other two will work.

[berty987]

The 987 and 986 have different ECU programmes (and ECU's) , even though they share the same heads and much of the internal engine parts. If you fit a 987 inlet plenum T its supposed to modulate independently from the cross flap that is in the other link tube between the inlet manifolds. Unless you get a custom ECU I cant see how you could get the plenum T to modulate correctly , so it may be better to simply fit the T without any control. I also suspect that the variocam on the inlet also adjusts based on the plenum T as would possibly ignition and fuelling. Assuming you are fitting the airbox as a performance modification, it may also be better to fit a cayman / post 2006 boxster plenum T rather than the earlier 987 boxster 3.2 model. The later model plenum used on the M97 engine uses the same airbox but has a larger throttle body ( 76mm rather than 68mm diameter). I would still sugest this is fitted without the vacuum control or if possible with a 996 3.6 manifold T which doesnt have the internal flap control. If you fit either the M97 76mm plenum or the 996 3.6 item you need to also fit silicone reducers to mate the T to the inlet manifold on each side as the diameters are about 10mm different. There is a write up on planet 9 under the articles section and a few posts on 996 plenum tees into 986 boxsters under the tuning part of the forum. Hope this helps.

[jaykay]

I would also be concerned as to where the flap is flapping without controls attached to it.

[Frank A]

I have the complete set up from a 2007 cayman S, Air Box to intake T. Still doing my homework on this, just trying to lay out my options before I do the install. I'm busy with school rite now and I have suspension upgrades planed for spring break so this project is on the back burner until I can more info on the update. My main concern about this is the MAF and what I may need in the way of programing in order to benefit from more air. I would like to take advantage of the flap in the intake t for low end torque. If the intake flap is actuated with the variocam I may try hijacking the signal from the variocam solenoid relay to actuate a relay for the additional vacuum solenoid. I may put it off until I can get some head work done. I recently saw a post on the Pelican Bord from someone who had adapters made to use the cayman S intake manifold on 996 heads.

In case you can't tell I got a real bad case of cant leave well enough alone!

[Brad Roberts]

I make adapters to install the CaymanS intake on *any* of the 9X6 heads. The guy who *probably* posted on PP was a guy out of San Antonio we did a set for.

[jaykay]

Originally Posted by Frank A

I have the complete set up from a 2007 cayman S, Air Box to intake T. Still doing my homework on this, just trying to lay out my options before I do the install. I'm busy with school rite now and I have suspension upgrades planed for spring break so this project is on the back burner until I can more info on the update. My main concern about this is the MAF and what I may need in the way of programing in order to benefit from more air. I would like to take advantage of the flap in the intake t for low end torque. If the intake flap is actuated with the variocam I may try hijacking the signal from the variocam solenoid relay to actuate a relay for the additional vacuum solenoid. I may put it off until I can get some head work done. I recently saw a post on the Pelican Bord from someone who had adapters made to use the cayman S intake manifold on 996 heads.

In case you can't tell I got a real bad case of cant leave well enough alone!

I intend on manufacturing a press fit sleeve for the 987 MAF housing. To bring it down to where the 986 tune can work with air flow. This diameter nicely matches the dia of the 987 74mm tb. This way I avoid custom programming issues

The 987 T flap is vacum operated. It may be that the vario cam change overs their signals could be made to run the flap and work but I fear you will get snap change in flap position as the cams phase (2500 rpm ?). Maybe this is okay as this a coast cruise rpm but if the phasing occurs at (4000rpm) you could be in the middle of a corner when you get cams and flap changing.....whomp!

The 987 would have vario cam plus which is gradual.

Sounds interesting let us know how you make out!

[Frank A]

The rate at which the flap opens can be regulated by the diameter of the vacuum line that feeds the flap bellows, larger diameter more volume transfer the faster the valve opens. The vacuum canister should have more than enough capacity to handle this. The plastic lines used currently have a 1mm I.D the combination of the small diameter and the volume air needed to actuate these devices does two things, regulates the time between normal and activated state, and lessens the affect of pressure pulses creating pulsed transition from normal to to actuated.
Besides I have always been a fan of a 2 stroke like power curve, just as long as it is consistent. And I'm the only driver on this buss!

[jaykay]

Originally Posted by Frank A

The rate at which the flap opens can be regulated by the diameter of the vacuum line that feeds the flap bellows, larger diameter more volume transfer the faster the valve opens. The vacuum canister should have more than enough capacity to handle this. The plastic lines used currently have a 1mm I.D the combination of the small diameter and the volume air needed to actuate these devices does two things, regulates the time between normal and activated state, and lessens the affect of pressure pulses creating pulsed transition from normal to to actuated.
Besides I have always been a fan of a 2 stroke like power curve, just as long as it is consistent. And I'm the only driver on this buss!

Yes. True I didn't think about the line size and diaphragm diameter...could be okay!

Hey I rode ported and polished RZ-350 for 7 years so I hear yah!

[BYprodriver]

Finally got the 987 airbox & maf tube in & made a hose to connect to 997 plenum & 74mm T/B. Hard to see much of the hose, maybe I can get a better pic on a sunny day. My engine is 3.6L so runs very lean unless maf is disconnected then it runs ok just a little rich. Next is the 996 flash.

[The Radium King]

just thinking a bit here: anyone try to push a 996 flash onto a 3.2 986 that has the larger cayman maf housing? ie, do what you've done but to a 3.2? would really allow you to reduce restrictions in the intake tract, but the maps might be off for the smaller displacement (maf reading would be correct so afrs should be ok)? is there a special flash for the 2004 anniversary edition that had the 3.2 with larger maf housing?

[The Radium King]

I guess an 04 anniversary edition tune wouldn't work as it's a 7.8 dme. still, a 996 tune *might* work - afr's would be fine, maf readings would be fine with a cayman maf housing. I think it would just be a question of the maps being able to deal with the fact that the rpms wouldn't correlate to the amount of air (3.2 vs 3.4 displacement) but I think that there must be enough room in the maps for this, otherwise lne wouldn't be able to say that a 3.6 bore works fine with the oem 3.2 tune (same thing only in reverse).

so, we need someone with a 3.2 to put a cayman airbox and maf housing in their car and push a 3.4 996 tune onto it and see if it runs ...

[onaFLYer]

Originally Posted by The Radium King

so, we need someone with a 3.2 to put a cayman airbox and maf housing in their car and push a 3.4 996 tune onto it and see if it runs ...

That is my most recent plan for my car...though it is not a 3.2 anymore. We tried some updated tunes awhile back to no avail. Currently running an updated stock tune which is better than it was, just not great. Having the car on the road for over a year now, and dealing with various issues from the beginning I'm ready to once again try and make it right. Looking at putting the IPD plenum and a 987 TB on it too.

Will report back once the 996 tune is tried.

[BYprodriver]

Originally Posted by The Radium King

I guess an 04 anniversary edition tune wouldn't work as it's a 7.8 dme. still, a 996 tune *might* work - afr's would be fine, maf readings would be fine with a cayman maf housing. I think it would just be a question of the maps being able to deal with the fact that the rpms wouldn't correlate to the amount of air (3.2 vs 3.4 displacement) but I think that there must be enough room in the maps for this, otherwise lne wouldn't be able to say that a 3.6 bore works fine with the oem 3.2 tune (same thing only in reverse).

so, we need someone with a 3.2 to put a cayman airbox and maf housing in their car and push a 3.4 996 tune onto it and see if it runs ...

I think it would run ok just possibly a little too much cam too early due to the 996 timing. I would have to compare the cam timing differences.

[BYprodriver]

Originally Posted by BYprodriver

Finally got the 987 airbox & maf tube in & made a hose to connect to 997 plenum & 74mm T/B. Hard to see much of the hose, maybe I can get a better pic on a sunny day. My engine is 3.6L so runs very lean unless maf is disconnected then it runs ok just a little rich. Next is the 996 flash.

996 flash works great for the 3.6L, I was surprised how much power this combo added! The intake roar is startling! New dyno test coming.

[Meir]

Originally Posted by BYprodriver

996 flash works great for the 3.6L, I was surprised how much power this combo added! The intake roar is startling! New dyno test coming.

Who did the 996 flush for you if I may ask?

[BYprodriver]

Originally Posted by Meir

Who did the 996 flush for you if I may ask?

I did with my PST2

[Bfan]

I am impressed. You are the man BYprodriver. Respect, respect

[Meir]

Originally Posted by BYprodriver

I did with my PST2

good to know you have one

[Paul]

Originally Posted by BYprodriver

I did with my PST2

When I reflashed mine, I got to see some of Porsche's humor while the download was taking place: