Second time at autocross, the second time it's happened.
An instructor there was saying that bouncing off the rev limited (on accelerator, not overrev from downshifting) is fine. Really?
After doing a few runs, there's a ticking sound like a loose valve adjustment. After sufficiently cooling down, and definitely the next day the noise disappears.
What is this noise and should I be worried?
(BTW I had my VANOS serviced a few months ago)
Its fine to hit thr rev limiter
Sounds pretty normal, run a different oil (10w40 is usually good) or top up to max or a little above before autocrossing next time to minimize noise. After sustained high RPM the oil doesnt reach/fill hydraulic lifters as efficiently, causing a little ticking. As long as it returns to sounding normal when cool, its fine
The more you beat your car, bounce it off the rev limiter the higher risk of something going wrong. Personally I don't like redlining engines regularly. Plus if you look at dyno charts a lot of engines fall off on power and torque before redline or when the limiter is activated. Then of course there's no reason too. Your car will only put up with it this kind of thing for limited amount of time before something breaks.
The valve tick is normal - as long as it goes away. It used to happen to me after every run at the track. If it bothers you, the quick and not harmful fix is an extra 1/2 qt of oil.
Blue Ridge Mountains
1999 2.8 Z3 Coupe
Arctic Silver
Thanks all, I appreciate it. There actually is a reason to do it (if going for time) and that's to reduce time--shifting to 3rd and back would dramatically lengthen lap time--considering the dropoff after max torque as getting more speed before hitting the next corner.
I mean it goes with use, but its not like just hitting redline is doing something unprecedented. Hitting redline here and there isnt really doing more harm than constant starts throughout the day.
Prolonged running at redline is a different story, as everything is running at high speed and heat etc.
Id argue starting and turning off your car a few times a day is more harmful for engine components than hitting redline once or twice.
u should hear most s50/52 cars after a 20 min track session......sounds like diesels..lol
https://www.bimmerforums.com/forum/s...ick+from+track
I had heard lifters get starved from hi g forces and hi rpms.......mine got better w/ overfills......and w/ a baffle......
....anyhew by drive home she was fine
but its sounds soooo bad...lol
Last edited by jrkoupe; 07-16-2018 at 03:41 PM.
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