maf and throttle body diameter

[jaykay]

My stock 2000 S intake pipe does have a small Helmholtz chamber built into it which I lost upon installing a 74mm TB.

These acoustic devices certainly do have performance enhancing merit. I have seen them in Titanium FI exhaust systems. I would hope that in the case of the Boxster intake pipe that the design intent was a more favourable performance result rather than just a noise reduction effort.

I actually found that I attained better throttle response below 4500 rpm by re-introducing a chamber into the intake tract. I also went from a 3,25" to a 3,0" tract diameter at the same time so perhaps this was the more dominant factor. Anyway this set up seems to work well with the 74mm TB and stock airbox. I measured these effects via 100% throttle position and engine rpm vs. time. Peak HP is a whole other matter!

With the above modifications, I also found that my custom snorkel gave better response above 4K while the stock snorkel slightly improved 3-4K throttle response. Looking at what is termed the "drip tray" on the stock snorkel and the direction of airflow into the side vent, I would guess that the drip tray was actually intended as an airflow director...so I left it on. Sooo if ever I track my Boxster again think I would fit my jaykay snorkel so that I might just pull by that pesky 964 in my run group.....

...yes my air box snorkel tang holes are just about shot!