[Plums]

G'day all,

I am slowly getting the Cobra ready for engineering and had a friend with a sound meter test the noise level.

I have quietened down (read bunged up) my sidepipes so much that it sounds just like a standard Commodore at the sidepipe exit. Even at 4000 rpm the noise coming from the pipe outlet is negligible. My problem is the noise coming from the engine bay...... The mechanical noise from the engine is far louder than anything else!!! This noise doesn't really seem to come from the extractors either, it's mostly just the mechanical noise of the engine. (And for you beer can knockers, it doesn't have any piston slap issues). I realise that alloy engines are noisier than boat anchors too...

With the engine at 4000 rpm it reads 93 dB, 50cm from the sidepipe exit (either side, doesn't matter)... If you hold the sound meter out in front of the radiator at 4000 rpm it reads nearly 96 dB. At the rear of the car at 4000 rpm the sound level is down to 88 dB. As a bit of a quick test, we put the front of the car in the shed and then closed the sliding garage door right up to the car, the sound level dropped down to 91 dB (not exactly perfect science but it did prove something)... If you could completely isolate the sidepipe exit, I reckon it would probably only read 86 or 87 dB....
For info, the sound meter is used for jap import certification and just came back from calibration in Sydney.

How on earth is this thing going to pass the driveby noise test?

How did you chaps pass the noise test??? Am I missing something or doing something wrong???

Thanks in advance,

Bobby Brown