Quote:
Originally Posted by HPsauce
Wasn't there a discussion about adding a Helmholtz resonator to control the drone?
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Spot on HP, that's what I'm planning to do, go back to the guy and ask him to fit Helmohltz resonators to each pipe at the back (starting just in front of the rear silencers and pointing back) and try to angle them so they aren't visible from behind. I did a bit of reading about them and the rpm resonance range vs length, so I'm thinking to ask to have them variable length and jubilee clipped so they can be tweaked. I'm going to guess 31" length for the initial try.
I am guessing its something to do with the resonance of the whole exhaust and its length and shape, and its temperature, because the drone is much less pronounced on cold start, but 5-10mins later when it warms up, in the same 1500-1900rpm range the drone appears.