OK...

I have been at several EFRA AGM's and the EFRA wants to lower down the noise for years. Something they are failing for many years by approving loud noise exhausts. But with one AGM they come up with 2 thoughts to lower down the noise in the future:

1) forbid AAC engines because the aluminium sleeve is making more noise.
2) max 5 port engines because less ports is making less noise.

Both to my knowledge picked out of nothing. I asked if they can show me a test based on 2 same engines with one AAC and the other ABC, they could not. Also as I was running modified 5 port engines I shared my knowledge that my 5 port engines were not making less noise than 7 and 9 port engines.

These thoughts of the EFRA never came back on the agenda, but it shows how stupid organisations can be.....