Different engine note between 986 and 996

[MNBoxster]

Hi,

It could be an Audible Illusion. With the engine/exhaust headers in the back on the 996, the sound waves may simply emanate from underneath the car whereas in the Boxster, some may bounce off the road back into the engine and either be absorbed, or as a wave function, get out of phase and cancel out some other waves, effectively lowering the sound you hear. Speculation to be sure. The only way to tell would be to use a decible meter on each under the same or near same conditions.

Happy Motoring!... Jim'99

[Adam]

Typically the larger the engine the deeper/throatier the sound. That is why 1.6L honda's sound like weed whackers and corvettes with the large displacement v8's sound the way they do. The increase in the 911's engine means the sound is deeper or "meaner" even though they use the same block as the boxster.

[986Jim]

Sound is also generated by the volume of air/fuel it's consuming and turning into power. The same car at 200hp sounds different at 400hp. So the fact that the 996 makes more power than a 2.7L will also give it a louder deeper harsher sound.

There are lots of variables, but displacement, head design, and hp are a few of the main ones. There are a few exceptions to the rule from small cars that sound really good like the VW VR6 motor is well known to have a beautiful sounding exhaust.