Im not sure if i can help you or not but try. Noises can be caused by worn or sticking hydraulic lifters due to low oil pressure . Another cause may be broken lock on tensioner. Just thinking about these things and take a look at them. Good luck.I need help identifying where this noise comes from, which starts exactly at 7,500RPM.
Visit AutoGuysLand to review what rpm should my car be at in case you need.
I don't have an exhaust system (straight exhaust pipe).
The noise appears even accelerating in neutral.
Yes, sometimes it has a very short scratchy sound when cold start. Can you show me a reference photo of the VVL Cam gear? ThanksIf you still hear the intake sound change at 6200 (or wherever your lift point is set) then your VVTLI is working and you have the high cam. If the VVL is not functioning you just don't get the fine-tuning of constantly variable intake cam.
Does the engine clatter for a second or two on cold start? If so that is a sign the VVL cam gear is at or nearing the end of it's lifespan.