[J.Jensen]

Have anyone done any measurements of the noise on their ERAs?

The Norwegian regulations for amateur built vehicles dictates the vehicle must meet a European sound regulation. The maximum sound level is 87db.

The microphone is to be placed 20" from the exhaust outlet, at a 45 degree angle in the direction that puts the mic the furthest away from the body.

Throttle is applied to bring the engine up to 3/4 of peak power rpm, or if that rpm is not available, 3/4 of engines maximum contructed? rpm. Say rev limiter anyone?

I´m guessing open pipes are definitely out the window, how quiet are the quiet ones at say, 4000 rpm for a 289/302/331?