helmholtz chamber - 550 SE

[jaykay]

Anybody with a 2004 550 Spyder...can you tell us if your intake has a helmholtz chamber if any kind? What does your air box look like and is the engine bay wall(s) different from previous 986s

Detailed pictures of the engine bay would be appreciated as well.

Just wondering if the 987 air box muffler we are shaving off is there for performance at all

[Topless]

It does indeed Jaykay. All modern Porsche intakes do but I don't have a specific pic of the 2004. It is the same intake as a 2005 987. I believe the 987/997 have a more sophisticated 2-stage Helmholtz chamber incorporated into the airbox which is vacuum activated to maximize intake tube resonance at different rpm.

Here are the patent descriptions from Porsche AG:

Intake system for an internal-combustion engine - Dr. Ing. h.c.F. Porsche AG

[jsceash]

I wish you would have posted this on Saturday. The motor I'm installed came out of a 04 550 Spyder. The Plenum has a sweep and down turn to the left. The throttle body ends up off center pointing slightly to the left. The connection piece to the MAF body is rubber, somewhat cone shaped with another sweeping turn and goes from the 68 MM throttle body to the 90 MM MAF body the MAF body bolted to the air box. I don't know if the air box was chambered but from the MAF to the Plenum was not.

The problem is I cut the sweep to make it fit into my IPD 74MM tube I threw away the small end of the connector but I have the rest. No chamber to those parts.


Just imagine another 6" sweep between Throttle body and the other tube section.

[jaykay]

Originally Posted by jsceash

I wish you would have posted this on Saturday. The motor I'm installed came out of a 04 550 Spyder. The Plenum has a sweep and down turn to the left. The throttle body ends up off center pointing slightly to the left. The connection piece to the MAF body is rubber, somewhat cone shaped with another sweeping turn and goes from the 68 MM throttle body to the 90 MM MAF body the MAF body bolted to the air box. I don't know if the air box was chambered but from the MAF to the Plenum was not.

The problem is I cut the sweep to make it fit into my IPD 74MM tube I threw away the small end of the connector but I have the rest. No chamber to those parts.


Just imagine another 6" sweep between Throttle body and the other tube section.

Thanks for the information...yes I thought I might be too late

So I take it that you are using the 987 box

[jaykay]

Originally Posted by Topless

It does indeed Jaykay. All modern Porsche intakes do but I don't have a specific pic of the 2004. It is the same intake as a 2005 987. I believe the 987/997 have a more sophisticated 2-stage Helmholtz chamber incorporated into the airbox which is vacuum activated to maximize intake tube resonance at different rpm.

Here are the patent descriptions from Porsche AG:

Intake system for an internal-combustion engine - Dr. Ing. h.c.F. Porsche AG

Thanks D. I will have a look at this material on a larger device when I can. It is interesting that this chamber is shown down stream of the MAF and that is how is appears in the 986 except the 550. Presumably the main function would be to prevent the MAF fouling you speak of.

The muffler camber in the 987 airbox is of course, upstream of the MAF so I wonder to what degree it will attenuate reflected acoustic pulses as these will be emitted on an consistant basis down stream of the MAF.

Perhaps we might reason that in the case of the 550 the helmholtz chamber had limited benefits. This might extend to the 987 but recall that the divert tee there has its own flap

I can't speak to the 997 but the 987 box has a passive, small round opening in the airbox flow path leading to a huge compartment which is baffled as I recall. Seems to be very sound muffler like.

Perhaps those with data capability could plot MAF signals before and after messing with the intake to see if significant disruptions result....if these are discernible

[jsceash]

987 parts manual drawing

[Timco]

I will post engine bay pics later. Also I can post a pic of the air filter tomorrow.

[The Radium King]

Here's a shot I promised jk - the 987 airbox in a 986 muffler clearance.

[jaykay]

Nice I like the way you trimmed it. So it looks like for a 2000 we need to trim up the box. When I was doing some other intake work I thought to myself how is that going to come out (air box) and this go in (987 air box). I think I will be rotating the front of the engine down

So we definitely need to bend the tab?