987 v 986 Air box

[BYprodriver]

Installing 987 airbox in my 986. Does anyone have a 987 S MAF tube for sale?
OR anyone thinking of buying a MAF sensor & won't need the tube?
PM me.

[jaykay]

What are doing to adjust the MAF housing diameter or are you doing a tune?

It's tricky to find one of these as a 987 take off as the correct size housing is required to have the car run properly.

...I need one as well

[JAAY]

I used a 2000 540i bmw housing. Cheap from ebay. Mine works great. I by no means have stock piping but It is working for my application with out a hitch.

[BYprodriver]

Originally Posted by jaykay

What are doing to adjust the MAF housing diameter or are you doing a tune?

It's tricky to find one of these as a 987 take off as the correct size housing is required to have the car run properly.

...I need one as well

I would like to avoid cuting off the end of the 987 airbox. I plan to flash my DME with the 996 flash & tune from there as needed. It would be easy to cutoff my 986 MAF tube & plumb it in but I want to keep it as oem looking as possible for CA smog checks.

I know there are 100's of disgarded 987 MAF tubes laying around 987 owners garages.

[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.

[Bfan]

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

[Paul]

Every time I work in that area, my hands look like I rubbed them on a cheese grater!

[The Radium King]

got it in - pull the intake, bend the tab - fuel rails stayed in ...

[The Radium King]

ok, what I think I've learned:

1. as per all the previous posts, air box will fit. it has a larger intake, much larger filter element, and larger output (3.25" OD vs 3" OD) - it is an improvement.

2. remove muffler. easy, messy work with a dremmel. get one of those automotive plastic welding kits from ebay ($25) to fix any mistakes you make. use a piece of the discarded muffler to weld on a plug over the muffler hole with the welding kit.

3. intake has to come off.

4. engine lid tab has to be bent up.

thanks to byprodriver et al for helping me through the steps above.

5. there are two vent lines (I think they are vent lines) with a bulky bracket that sits right under the new air box. this bracket has to come off for proper fit. I am also going to saw off the stub bolt that mounts the bracket to avoid rubbing on the vent lines.

6. the oem air box mounts with three bolts. the 987 air box mounts with two bolts and a plastic press-on fitting. in the 987 the highest, furthest back mounting point is a stub bolt and the air box has a plastic fitting that presses onto this bolt. make sure you get this fitting when you get your air box (part # 987 110 141 00). take your original bolt, saw the head off and thread it into the mounting point. the new plastic fitting can press onto this.

7. the air box outlet has a flange designed to mate specifically to the 987 maf housing. realise that if you use this maf housing it has an ID of 3.25" so will not work with a standard 986 tune (the exception may be the 2004 anniversary edition, but this is a 7.8 dme flash and won't work with pre-2002 cars that have the 7.2 dme).

options are (1) try a 996 flash (don't know if it will work, but will find out in a month or so) (b) get a custom flash (big $$$) or (c) use a maf housing with a 3" ID. for 3" ID maf housings, the easiest is to saw the maf housing off your oem air box. note that you lose the screen before the maf if you do this and should sort something else out for this. otherwise, many bmws use the same bosch mafs as porsche, so you can get a 3" ID bmw maf housing with screen and use one of those (I have model numbers if anyone is interested).

the issue becomes mating the 3" ID maf housing to the flange on the 987 air box. easiest is to saw the flange off and get a silicone coupler that joins the two, but what I've found is that, while the air box outlet has an ID of 3.25", the flange itself has an ID of 3.5". I've taken a 3.25" to 3" silicone reducer and found that it is a press-in fit to the flange. to make it more robust I took a thin-walled 3.25" coupler and sawed-off a 1/2" band. I inserted this band into the 3.25" end of the reducer to reinforce it. now the silicone reducer sits very snug into the end of the flange.

this is still a work in progress, so I reserve the right to change my info at any time. again thanks to the folks helping me with this. I think that 997 plenum, 987 air box, tb and maf housing, and 996 flash is going to reinvent the 3.2 for little $.

[986968]

Sorry to all for the late discussion.

I have a 2.5, and may I ask is it possible to change the airbox from Cayman S to the 2.5 engine?
If it's possible, is it even to change the piston to the 2.5 engine?

I realise the MAF for 2.5 and 2.7 is different.
If that's the case, does it mean I need to also change the Cayman S MAF to adopt the Cayman S Airbox in the 2.5 engine?

[epapp]

Since the people doing this mod would probably know:

I am trying to get some wires from the drivers side grille, through the airbox somehow and into the engine bay. When I was last checking, the stock airbox seems pretty closed up, even pre filter, and there is no where to sneak some wires through.

Anyone who has taken the airbox out, is there some space I'm missing/a good place I can drill a small hole pre filter?

Thanks