At about 4000 rpm there is a weird noise. Sounds like a cross between a woosh, a slurp and a vibration. I guess it's some sort of valve opening somewhere. Comes in about 3800 and is gone again about 4200. Anything to worry about?
I had a similar noise on a BMW which was the VANOS kicking in. Some fancy quad cam power boosting thing.
No significant change in performnance at that point either. Guess it's more or less full power at that point anyway but no major jolt or dip in power unlike the BMW which threw you into the back seats when it kicked in with it's magic cam thing.
Don't know. I guess so as it sounds like a Vanos, VVT type thing, but for some reason I can find virtually no "Facts" about the 1.8 16v. Even the haynes manual misses this engine out. I was hoping that someone on here may know about the details.
Bit worried in case it's some bypass valve or such thing and it's struggling to open. For example my old motorbike had a valve in one of the exhausts that regulated the back preassure in the heads. This made all sorts of funny noised when it got stuck and really dropped the power.
Is there a more technical forum on here somewhere as most of the posts seem to be fairly owner questions rather than more involved mechanical questions. I'm a bit new to this site so do not know if I'm perhaps postign in the wrong bit.