[Hans-Olof Blom]

In Sweden the measurements are done during full acceleration. The person doing the test will drive about 30mph in second gear and approx. 30ft before the measuring point he floors it. The allowed level is 85dBA.

I stuffed my side pipes with 6 steel wool balls in each pipe and added a plug made from expanded metal to keep everything in place. See pictures!

I adjusted the carb linkage so pedal to metal was only about 70% of full throttle.

My Cobra was really quiet and when I heard it during the test I was sure it would pass.

BUT, I was told to come back and WITH mufflers. The measured sound level was 90dBA so it was not even close.

After my first attempt last fall the weather was too bad for another try. But within a qouple of weeks I will try again. I have now added a construction made of Al-discs on a wire with tubes as spacers. It is now very very quiet but a bit hard to start.