Quote:
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