need to loose some DB's... help

[spud69]

"Position the vehicle within the authorised test area. With the sound meter horizontal, set the microphone height so that it is at the height of the exhaust outlet or 200mm from the ground, whichever is higher.
a.
At an angle of 45 degrees to the exhaust outlet in the direction which gives the greatest distance between it and the vehicle contour
b.
At a distance of 500mm from the exhaust outlet.
With the vehicle at normal operating temperature, run the engine at ¾ of its ‘maximum power’ speed, and note the sound level reading obtained."

Abstract from the IVA manual, check your distances are correct. But it states that it's 3/4 of the rpm at engine max power so you can get the test revs reduced by showing that the max power is at, say, 6000rpm so testing the noise at 4500rpm. Maybe take some documentary info stating this.

Should reduce the dB a bit, 'tis a lot to loose though 18dB

Regards....AndrewH