Metal Clashing sound with AR DP on Cold Start
I have some questions as I just had an AR Catted DP installed on my E90 and noticed some changes.
I noticed that on cold starts, especially the first start of the day, I would hear a metal clashing sound the moment I start my engine that lasts for a few seconds.
If I start it turn my car off and start it again, it does the clashing sound again (not always), but for only like one second.
When the car is still warm and I start the engine, usually there's no metal sound, but sometimes there's still a hint of that metal clapping sound.
Also, sometimes, when I accelerate and rev the engine slowly, I would hear this faint metal vibration that I did not observe before installing the DP. Maybe the stock DP covered up this noise.
I'll take a video of this tomorrow morning, but in the meantime, is this normal for a DP? Or will this be a potential problem?
Thanks for your feedback!