987 v 986 Air box

[The Radium King]

funny you ask - in my garage prepping for it as we speak. decided to wait until i have my new exhaust on to maximise flow before i do it. that means welding as i have an early set of the chinese headers and the O2 bungs are a little exposed. pm byprodriver as he's done it, albeit on a 3.2 taken to 3.6.

[Coaster]

How happy have you been with the stock 3" up till now? Obviously you think there is more if you are going to flash after fixing the headers, but curious how it ran for you after the swap.

[The Radium King]

its running great - no cels , no issues. more power? no idea. i want to try the 996 tune for three reasons:

- curiosity,
- sems silly to me to reduce the intake diameter for the maf housing, only to increase it again once past the maf housing, and
- 911 3.4 makes 300 hp. using the same ratio of hp:displacement, the 3.2 should be making 280 hp. the 3.2 and 3.4 share cams and bottom end, so most of the power must be lost in tune, intake and exhaust (those in the know say the 3.2 heads flow quite well, so no work needed there). this thread and ohers talk about upgrading the 986 intake with 987, 996 and 997 parts, and there are good, inexpensive exhaust solutions out there, so the last piece is the tune. if it works then you have a 30 hp gain with mostly oem bolt-ons. and for not too much money ($300 chinese exhaust, $50 for 1/2 hour labour to push the tune, $300 intake parts).

[notech]

Hello guys,
I'm planning to fit 987 airbox, butterfly and plenum all in one.
Have all the parts, silicone reducers for plenum but missing how to connect from 987 butterfly to 987 airbox bit, is there a Porsche part for that?
Plus it does seem that the engine bay is very very tight, can you confirm the 986 airbox can be removed without engine removal?
what would be the removal order? 1-plenum 2-manifold 3-airbox?
where are the manifold screws located?
Sorry many questions..
photos are going to follow and I plan do make a brief video when will be replacing parts so others can benefit.
attached my cut on the airbox.
Cheers,
Ser

[Reebuck1]

Don't forget to cover the hole in the back. I used fiber glass. I had the motor out when I put my box in and it was still difficult then. I think it would be really hard installing with the motor in the car.
I also had to cut off the flange closest to the throttle so I could get my 3.5" silicon tubing to fit on the air box.

I installed a 996 3.4 motor in my 986 using the 987 air box but it was a really tight fit.
If I would have needed another 1/4" it would not have fit. If you want some pictures I can send them.
Good Luck

[rfuerst911sc]

Brad I sent you a PM with a question. Thanks in advance.

[notech]

Thanks to all.
So at the end no one made this mod to a 986S with engine in?
I really would like to avoid to remove the engine if its possible.
cheers

[Bfan]

I did it while I had the engine out, but the saying on the street is that it is possible with the motor in the car if you remove the manifold on the left side. That sounds very likely to me. But removing the manifold is not one of my favorite tasks, the bolts are hard to get to and be prepared to scratch the back of your hand.....

[notech]

Thanks, feeling this is getting on the right track.
Is there a manual I can refer to on removing the manifold next to the airbox side?
Can someone please confirm the Porsche ID number for the tube linking airbox and throttle body?
much appreciated

[The Radium King]

to plug the hole get one of these:

80 Watt Iron Plastic Welding Kit TPO TEO PP Rod Mesh Auto Car Welder Repair Kit | eBay

and use a piece of plastic from the muffler you just cut off.

there may be info on removing the intake manifold here:

Porsche Boxster 986 (1997-2004) / 987 (2005-2008) Technical Articles | Pelican Parts

otherwise workshop manuals are here:

Manuals_Original

only the driver side manifold has to come off. I couldn't get mine completely out because of the aos tube, but was able to move it to get enough room. use your dremmel to cut the old airbox into pieces to get it out. the new one will go in with some contortion - to make your life easier, saw off the tab at the back of the engine compartment lip as per reebuck1, and bend the driver side tab for holding the engine compartment lid out of the way.

there is no oem tube to join the airbox and the throttle body. the 987 airbox is designed to work with the 987 plenum which has a big bend in it. the plenum you are using doesn't. you will either have to fab your own, or check with ipd - they make a tube that will join a 987 airbox to their plenum (which is about the same geometry as the one you are using).

[Bfan]

I would advise you to take lots of pictures of every step and mark every electric connection that you open. I have to emphasize this. On an other note I would say that this is a fairly straight job. The manifold is held by 6 M6 screws that you use 10 mm socket on. They go straight down into the head and are a bit hidden under/behind the manifold. Be careful not to over tighten them when you put it back together. Torque to 10Nm (7.5ftlb). That is about the force you get with a big screwdriver. But I would strongly advise you to get a torque wrench for this job.
And one more thing. You might want to open the hatch in the firewall, that is behind the seats, under the carpet to get somewhat better access to some of the bolts and get some light in under there.

[The Radium King]

other things I am remembering from the job - your intake manifold will also be constrained by the fuel rail - watch the injector tips. you'll also need part #6 on this diagram to keep the insall as oem as possible:

http://www.********************************************.com/porsche-parts/hardparts.php?dir=987C-06-08&section=106-00

otherwise, you may encounter a bit of fuel vent line interference at the bottom of the air box; you may need to saw-off the fuel vent line retaining clip boss to get the air box to sit flush against the inner wheel well.

[notech]

As promised, pics of the 987 intake transplant to 986S:

A view over the 987 / Cayman airbox, cut to fit into the Boxster. Hole was sealed later reusing some plastic cuts and glue, plus thermo isolation tape.


Starting opening the engine window

[notech]

Part2

[KRAM36]

Hard to tell by reading through all this, but did this end up being successful mod?

[Reebuck1]

I followed these instructions very closely and they worked great for my 3.4 996 motor swap. I did not use part #6 in the diagram...instead I used a long 10mm (40mm)bolt with a large washer. Been running it for two months and it works great!!

[KRAM36]

I should rephrase what I posted.

Hard to tell by reading through all this, but did this end up being successful mod for a 3.2 engine?

I've read stuff like car running too lean and MAF not working for the 3.2 engine.

Also the images notech posted will not display for me.

[KRAM36]

Anyone confirm this working on a 3.2 engine? If so what did you have to do to make it work correctly.

I have the month of February off and would like to do this mod if it works correctly.

[edc]

What do you mean by work on a 3.2?

The early 987s were 3.2 and the late run 550 is also a 3.2 and both used the 987 based airbox.

[KRAM36]

Originally Posted by edc

What do you mean by work on a 3.2?

The early 987s were 3.2 and the late run 550 is also a 3.2 and both used the 987 based airbox.

Have you read this? It's a mess of MAF problems and the car running too lean.