I think that is a function of the length (mostly) of the tubes in your
intake manifold. Tuned, no doubt to coincide with the torque peak of the
camshaft. What you may hear most, though, is the resonance in the
exhaust system, mostly due to the length of the elements in the exhaust.
That's my theory and I'm stickin to it.

Al Brase

>
>I believe this is right around 4 grand in the stock vanagon. If you listen
>to the engine you will hear the air box resonance at that speed as well
>taking advantage of resonance air induction which Porsche also uses to gain
>a 2-3 psi boost in intake pressure.
>
>Doug
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