Always a nice one, strange noises at least this one is consistent in turning up, so here goes:

I searched and did not find the answer i was looking for. My 2004 VIII has the alternator (i suspect its the alternator) whine as in this post: https://www.evolutionm.net/forums/sh...+whine+whining posted by webguy330i in 2003.

So nothing to worry about there, but here's the thing.

When shifting from 4 to 5 at aprox. 160kmp/h (100mph) there's a sudden plastic rattling noise coming from the passenger side. At first i thought there was some plastic part hanging loose from the wheel arch wich started to rapidly move by the wind, so i checked and placed some tierips to fasten up things better. That did not help. Strange thing is it only occurs suddenly from 100mph in 5th. not in any of the other gears under hard acceleration or slow acceleration. It seems to me that when i shift to 5th tension comes of the alternator and the bearings start to rattle. I have not taken it beyond 100mph yet to see if the sound disapears until i can pinpoint it more exactly.

I also hear the same noise but very, very soft and hardly noticable when lightly revving it stationary to 1100-1200 rpm (in neutral, so i dont think (hope) it's the tranny) then it's either gone because of more tension on the belt(?) and/or overruled by the rest of the engine noise & exhaust.

I have not yet tried recording it, i dont want to take it there to often before i know a bit more as to what it can be and if it's possibly damaging.

Anyone had anything simmilar, i know it's always hard to say anything sound about odd sounds.

Thanks in advance

 

Do you have a stock DV(or BOV)?

 

I have installed the APS dual vent BOV about 6 weeks back to replace the stock plastic. The sound appeared this week.


Mods:
ECUteck tune (296BHP, 405NM torque)
Invidia catback
Injen air intake.
ACT clutch & flywheel kit
No other engine related mods are installed.

 

Do you have a carbon fiber hood?

 

No, no body mods.

I checked for loose pieces wich could start to move by the wind. tightened a few plastic parts with tie-rips. checked the wippers the mirror etc. I think it's something mechanical.

It only suddenly occured this week and only in 5th at 100mph. and very very faint when iddling at 1100-1200 rpm.

I'll keep looking though