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So I received my Durametric software in the mail and got it installed and hooked up to my truck. Very cool stuff... a little less info than I wished for, but way better then the wooden ouija board I was using previously.

I started with a simple test to see how well those odd looking intake tubes really work. With all the trouble that mass flow sensors have I was flabergasted to see that Porsche now has two of them!!! On top of that, they only feed a single throttle body. I figured that with two they would at least feed separate banks of the motor, but aghast... I found out that the truth is only one throttle body for all 4.5 liters.

Anyway, once I saw that I could monitor the output voltages of the sensors independently I was immediately excited (yes, I said excited... you might be a car nerd if you get excited about that one). So the very first data logging test I ran was to monitor those two outputs as well as engine speed (I did throw in misfires for good measure but not one hit so that is a moot point).

As the logging progressed, I varied engine speeds and how quickly I snapped the throttle open and closed. (I also learned that the Cayenne limits revs to around 4K when in Park).

My hypothesis was that one side or the other would be the favored side for sucking in air... whether due to less clogged filter or better postioning of the intake snorkle or whatever, I figured one side would flow more and the computer woudl simply add the two values to measure the total air flowing through the single throttle body. Well, my hypothesis proved incorrect (I believe the technical term is that it was "rejected"). Both mass flow sensors were pretty much dead nuts on top of one another. There were four sampling points where they varied... yup, two were higher on the left and then two were higher on the right. Did not seem to matter whether it was opening or closing the throttle. **** it... they were both sucking equal amounts of air. I figured there would be an easy upgrade to increase the flows so that they matched.

Anyway, it appears that the technical team at Porsche did an awesome job... can't believe I doubted them :)

So what does this all mean? Well if you made it this far in the post, it means you are a car nerd too. But what it really means is that sometime this week, I will remove one of the air filters and do some more data logging to see just how much restriction is introduced by the aircraft carrier sized paper elements that are lurking under our hoods.

Good luck and good night.

If anyone has any additional info that might help me in my quest for cheap efficiency improvements... please point the way! In the spirit of true research, I am open to any and all viable suggestions.



2004 Cayenne S

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