If you want to make meaningful comparisons, then you must compare like with like. No two sound meters are the same, no two locations have the same accoustic properties. Ambient humidity, temperature and air pressure will affect the readings. The same motor will produce different decibel readings when static or under load. Noise from the engine, other than exhaust emission (such as intake roar) will have an effect on the total noise produced, so it is unrealistic to try to make such comparisons meaningful.
The only things that actually matter are the noise as measured by the offical marshal at the event, and the published maximum permitted for that event.
There are many different principles and designs of exhaust systems and mufflers around, some of which work very well, and some that do not. Some reduce noise very effectively, some do not. Some systems which at first glance look very inefficient reduce noise to acceptable levels at the cost of only a few BHP. Some absorb more power than others. Some are very heavy or ugly, some are relatively light or aesthetically pleasing.
The bottom line is that we are using big powerful motors that procuce a lot of noise.......and it's beautiful.
The only things that actually matter are the noise as measured by the offical marshal at the event, and the published maximum permitted for that event.
There are many different principles and designs of exhaust systems and mufflers around, some of which work very well, and some that do not. Some reduce noise very effectively, some do not. Some systems which at first glance look very inefficient reduce noise to acceptable levels at the cost of only a few BHP. Some absorb more power than others. Some are very heavy or ugly, some are relatively light or aesthetically pleasing.
The bottom line is that we are using big powerful motors that procuce a lot of noise.......and it's beautiful.