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Discussion Starter #1
After several sustained top speed runs deep into 4th and 5th gear, supposedly with the diffuser flapping in the wind, and pegging the needle near the rev limiter in order to keep a Panny S and a late model 750i in line, I pulled into the garage in the dead of the night only to hear a rapid fire metallic popping sound literally coming out the exhaust pipes after I shut the car down. I had hear of similar high pitched popping sound coming from the rear calipers of an E92M3CP due to metal contracting after hot laps at the track, but I haven't been using my brakes all that much immediately prior and I'm 99.99% certain the sound was coming from the exhaust. Has anyone experienced this? I haven't started the car since.
 

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Can you pinpoint where the sound is coming from? You said you hear it coming out of the pipes but it can originate anywhere in the exhaust line. If it sounds like the brakes of that E90 M3 at Lime Rock, it may be an exhaust element cooling down.
 

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Sounds like typical exhaust cooling to me. Both my 530i and 749i/6 do it after driving it for a while with the temps up.
 

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Yes, they are perfectly normal sounds of the heat expanded metal from the pipes finally getting a chance to cool off. No worries.
 

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Cool, good to know that's normal. I never heard it before, its like small pellet gun hitting sheet metal, 4 to 5 times per second. The sound was coming out of all 4 exhaust pipes, but the sound seemed to originate from within the muffler, not upstream. The weird thing is the car was running extremely powerful right before. I know vantaam5 said the car runs strongest right before chain guide fail so maybe I will have some work to do.
 

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Cool, good to know that's normal. I never heard it before, its like small pellet gun hitting sheet metal, 4 to 5 times per second. The sound was coming out of all 4 exhaust pipes, but the sound seemed to originate from within the muffler, not upstream. The weird thing is the car was running extremely powerful right before. I know vantaam5 said the car runs strongest right before chain guide fail so maybe I will have some work to do.
Im sure it's only the pipes cooling off. My rotors ping so loads after they get hot. I have the 2 piece floating rotors.
 

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I was going to say the same, sounds like exhaust pipes cooling off. How did you do against the two vehicles in question?
 

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I get those sounds when I drive my e38 740iL hard. It takes a good 2-3 minutes for that car to stop making noises. It is just the pain to engineer around fact that all materials expand and contract at a different rate.
 

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I get those sounds when I drive my e38 740iL hard. It takes a good 2-3 minutes for that car to stop making noises. It is just the pain to engineer around fact that all materials expand and contract at a different rate.
The competition brakes have steel discs and aluminum hats, so that explains the popping, but my car has stock one piece exhaust, the popping and pinging barely slowed down in the 2 to 3 minutes I roamed around the garage investigating the sound. It was 1:30 in the morning so I didn't wait for it to quiet down before hitting bed. It's still odd I never had this happen even after triggering coolant temp high warning on the track, but the car did feel very powerful.

I was going to say the same, sounds like exhaust pipes cooling off. How did you do against the two vehicles in question?
As far as the runs, the 7 was cake, but the Panny actually hang tight, we cruised happily ever after up to the speed limit. :byee55amg
 

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Yeah as others have said, normal on mine. One piece stock exhaust too, mainly comes from the silencers. One of my friends commented on it when I got to his house "you've been driving this thing huh?" he said when he heard it. I said just no more than normal LOL.
 
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