Rattle on throttle after catless downpipe install

kenken662 · 09-13-2023, 10:40 AM

Hi all, recently installed a VRSF catless downpipe on my 2021 M240i 6MT, and have a pretty bad rattling sound on throttle, most noticeable around 2-3000 RPM.

have made sure there is space between the exhaust system and bracing / heat shields so I don't think it's that. My theory is that it's either wastegate rattle amplified by going catless, or vibration from the exhaust valve when going catless. Whatever the sound is, it wasn't there with the stock downpipe. I have checked that the valve clip is not broken, and it is working properly. It may also be the turbo to downpipe connection, however I tightened the V-band super tight so I doubt it.

Has anyone with catless downpipe experienced wastegate rattle on the B58?

Thanks

XutvJet · 09-14-2023, 03:31 PM

Are you certain it's not rod knock? 2000-3000rpm is the rod knock sweet spot.

09-13-2023, 10:40 AM	#1
kenken662 New Member 5 Rep 15 Posts Drives: 21 F22 M240i 6MT RWD Sunset Or Join Date: Jul 2022 Location: Bay Area, CA iTrader: (0) Garage List 2021 F22 M240i 6MT ... [10.00]	Rattle on throttle after catless downpipe install Hi all, recently installed a VRSF catless downpipe on my 2021 M240i 6MT, and have a pretty bad rattling sound on throttle, most noticeable around 2-3000 RPM. have made sure there is space between the exhaust system and bracing / heat shields so I don't think it's that. My theory is that it's either wastegate rattle amplified by going catless, or vibration from the exhaust valve when going catless. Whatever the sound is, it wasn't there with the stock downpipe. I have checked that the valve clip is not broken, and it is working properly. It may also be the turbo to downpipe connection, however I tightened the V-band super tight so I doubt it. Has anyone with catless downpipe experienced wastegate rattle on the B58? Thanks
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09-14-2023, 03:31 PM	#2
XutvJet Major General 5554 Rep 5,372 Posts Drives: 2011 Cayman Base, 2016 M235 Join Date: Mar 2016 Location: Kansas City iTrader: (-1)	Are you certain it's not rod knock? 2000-3000rpm is the rod knock sweet spot. __________________ The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
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