need to reduce top speed, help!

[swissdoo]

hi helpers,

i am aware that this is the PWC section, i think you guy`s will be the best to help me out.

my problem made short, to pass the noise emmision test over here in switzerland i have to reduce my top-speed from my challenger 230 SE round 10-15mph.

this has to be done in the pump, i am not allowed to lower the revs.. they check that before the test begins..

my main problem is the water sound, we have done several tests and the engine sound is now ok, after having the engines out to dampen the engine room.. ;(

so what will give me the best result? change the nozzels or sand out the ware rings? i like the ware ring way because its very easy to change the modd back to stock after the test. dose anyone have any experience how much i will have to sand out to get my 10-15mph loss??

or any other ideas?? thanks so much for any help , patrick

 

[D 5UPE]

So to stop your noise emissions your going to burn more fuel getting from A to B. :rofl:

Hope this European law stays over there. LoL.

Is there no over revving adjustment on these as pwc engines have. Or change the waterbox for a bigger one maybe.
Hope you get a quick fix on that one.

 

[PWCdoc]

I'd try either an in-line silencer or dump more water into the exhaust before it exits the hull.