Intake/Exhaust Upgrades for a 2003 3.2 S

[drumboxer]

Ok, you guys are awesome. Please take a look at my notes/questions below:

Originally Posted by The Radium King

so, just to get my terminology straight, and working from out to in, you have:

Thanks for clarifying, I want to be sure I am on the right page: Here is what I was planning to use:

snorkel - part of the airbox? If so, 987
air box - 987
maf and holder - 987
intake pipe - Sounds like I need to fabricate one? (I have a manual trans btw)
throttle body - 996
plenum - 996
intake manifold - 996

from what I gather (haven't done this, but some have) the 996 intake manifold will fit on the 986 motor, however it (a) is taller and requires the 987 engine cover, and (b) only has two of the six fastening points match on each side. as a result, you have to (a) tap two holes on each side, and (b) fabricate two brackets on each side. Thank you, this is helpful. I am planning to use the 996 manifold, so I guess tapping new holes will be necessary.

re the tune, it is required only if you change the diameter of maf holder (different diameter means different air readings to the computer). ie, if you use a 987 maf holder to match your new air box then you need to retune you engine as it is a larger diameter than what the computer expects. you can reuse the maf holder currently in your car by sawing it off your old air box, or find a bmw unit (or any car that runs a bosch system) of the same inside diameter; this way don't have to do anything with the computer. If I have to send the ECU away to retune anyway, would I be better off with a custom tune that accounts for my motor and each modification made?

the design of the intake pipe from the maf holder to the throttle body will depend on your decision on what you are doing with the maf holder. I reused by original maf holder and was able to get away with reusing the old intake tube and getting a 90 degree reducing elbow to mount on the throttle body (the inside diameter of the new throttle body is 3" but the outside is 3.25" due to the thickness of the lip - you want an elbow that reduces from 3.25" to 3"). probably the best approach is to get the manifold/plenum/throttle body on, and the air box and maf holder in, then figure out what you need to get the two to join. if you want a super duper oem look, then IPD make a pipe for the cayman that should do the job (the IPD plenum is about the same dimensions as the 997 plenum, so should fit right up provided you take the 987 maf holder route). - And if I intend to use the 987 MAF holder? My understanding is that this is optimal so as to not create a bottleneck with the smaller diameter 986 housing.

[BrokenLinkage]

But does the 550 SE have a special tune to reflect the use of the 987 airbox & maf/holder? If so, can this tune be used with a five chain engine (ie my 2001s)?
It then uses the same throttle body diameter as any other S, with the same plenum & intake manifold as stock?
Am I correct in thinking there is not much benefit in reducing the restriction in one part of the intake, if it is left in place elsewhere? (Like the rate-limiting-step in chemistry). So if I am not on board with drilling new mounting points and installing the 996 intake manifold, with the attendant use of the 987 engine cover and loss of the rear shelf speaker bar, then this is pretty much a waste of time?
Or can I pick u a few horses just using the 987 airbox, modded to fit the stock MAF, plus a larger throttle body, without a retuning of the ECU?
Thanks everybody for sharing your knowledge with those of us lower on the ladder of flat six enlightenment.

[BYprodriver]

Originally Posted by BrokenLinkage

But does the 550 SE have a special tune to reflect the use of the 987 airbox & maf/holder? If so, can this tune be used with a five chain engine (ie my 2001s)?
It then uses the same throttle body diameter as any other S, with the same plenum & intake manifold as stock?
Am I correct in thinking there is not much benefit in reducing the restriction in one part of the intake, if it is left in place elsewhere? (Like the rate-limiting-step in chemistry). So if I am not on board with drilling new mounting points and installing the 996 intake manifold, with the attendant use of the 987 engine cover and loss of the rear shelf speaker bar, then this is pretty much a waste of time?
Or can I pick u a few horses just using the 987 airbox, modded to fit the stock MAF, plus a larger throttle body, without a retuning of the ECU?
Thanks everybody for sharing your knowledge with those of us lower on the ladder of flat six enlightenment.

Yes the 550 has a special tune & a 7.8 DME so you must have the 7.8 DME to use it.
T/B & plenum are standard size.
I believe the larger intake hose will help even with a slight diameter reduction midway.
You can install the whole 996 intake manifold & lower the engine mounts for clearance.
987 airbox will flow roughly double the amount of air as the 986 airbox, + any other enhancement parts. DME must be programmed with correct MAF tube diameter in order for MAF to calculate intake air volume. If diameter stays the same reprogramming is not required.