N54 turbo rattle disappears after 1-2 mins of driving

Protolate · 12-02-2019, 09:43 PM

I currently have a 2007 E92 335i, and it has some pretty bad wastegate rattle. I installed MHD, but kept it on the Stage 0 map, only with linear throttle mapping. When I first start the car, the rattle is very bad on deceleration. It completely disappears after 1-2 minutes of driving. I originally thought it was because the engine was cold. However, I waited for the rattle to disappear, and then I shut the car off and turned it back on. The horrible rattle was back, 10 seconds after I had been driving with no rattle at all. This leads me to think that this could be an ECU thing? Could anyone inform me what causes the rattle to disappear, and how I might be able to completely get rid of it right after it starts up?

relative4 · 12-02-2019, 11:17 PM

Are you certain it's not the exhaust flap? Have you tried the wastegate rattle reduction feature in MHD?

Protolate · 12-03-2019, 10:22 PM

I did the golf tee mod, so I'm pretty sure it's not the exhaust flap. As for the wastegate reduction feature, I tried it but did not notice a huge improvement, so I just turned it off.

iqraceworks · 12-04-2019, 06:55 AM

Quote:

Originally Posted by Protolate

I currently have a 2007 E92 335i, and it has some pretty bad wastegate rattle. I installed MHD, but kept it on the Stage 0 map, only with linear throttle mapping. When I first start the car, the rattle is very bad on deceleration. It completely disappears after 1-2 minutes of driving. I originally thought it was because the engine was cold. However, I waited for the rattle to disappear, and then I shut the car off and turned it back on. The horrible rattle was back, 10 seconds after I had been driving with no rattle at all. This leads me to think that this could be an ECU thing? Could anyone inform me what causes the rattle to disappear, and how I might be able to completely get rid of it right after it starts up?

Have you tried adjusting your wastegate rods? As far as the noise coming and going.....could be something as simple as temperature change. Have you checked your vacuum lines? It could be a faulty wastegate solenoid sticking...or acting up also.

Protolate · 12-04-2019, 07:23 PM

I adjusted the rear wastegate rod, and there is very little back and forth play, but some side to side. I originally thought it was a temperature change. However, if I wait for a minute for the rattle to completely disappear, and then quickly turn the car off and on, the rattle returns. I doubt there is a large temperature difference after restarting it.

The rattle consistently disappears after a minute, so I don't think it is a sticky solenoid. As for the vacuum lines, I think the previous owner replaced them, as they are braided and not the standard OEM rubber ones. I don't know how else to check for a vacuum leak though.

12-02-2019, 09:43 PM	#1
Protolate New Member 1 Rep 9 Posts Drives: BMW 335i Join Date: Nov 2019 Location: Orange County iTrader: (0)	N54 turbo rattle disappears after 1-2 mins of driving I currently have a 2007 E92 335i, and it has some pretty bad wastegate rattle. I installed MHD, but kept it on the Stage 0 map, only with linear throttle mapping. When I first start the car, the rattle is very bad on deceleration. It completely disappears after 1-2 minutes of driving. I originally thought it was because the engine was cold. However, I waited for the rattle to disappear, and then I shut the car off and turned it back on. The horrible rattle was back, 10 seconds after I had been driving with no rattle at all. This leads me to think that this could be an ECU thing? Could anyone inform me what causes the rattle to disappear, and how I might be able to completely get rid of it right after it starts up?
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12-02-2019, 11:17 PM	#2
relative4 Major 611 Rep 1,272 Posts Drives: '08 335xi E90 MT stage 1+ Join Date: Feb 2019 Location: Denver, CO iTrader: (0)	Are you certain it's not the exhaust flap? Have you tried the wastegate rattle reduction feature in MHD?
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12-03-2019, 10:22 PM	#3
Protolate New Member 1 Rep 9 Posts Drives: BMW 335i Join Date: Nov 2019 Location: Orange County iTrader: (0)	I did the golf tee mod, so I'm pretty sure it's not the exhaust flap. As for the wastegate reduction feature, I tried it but did not notice a huge improvement, so I just turned it off.
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12-04-2019, 07:23 PM	#5
Protolate New Member 1 Rep 9 Posts Drives: BMW 335i Join Date: Nov 2019 Location: Orange County iTrader: (0)	I adjusted the rear wastegate rod, and there is very little back and forth play, but some side to side. I originally thought it was a temperature change. However, if I wait for a minute for the rattle to completely disappear, and then quickly turn the car off and on, the rattle returns. I doubt there is a large temperature difference after restarting it. The rattle consistently disappears after a minute, so I don't think it is a sticky solenoid. As for the vacuum lines, I think the previous owner replaced them, as they are braided and not the standard OEM rubber ones. I don't know how else to check for a vacuum leak though.
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