M235i VRSF Downpipe & Res Delete Issues

gt-[r] · 03-17-2021, 04:18 PM

Hello. I have a m235i and I have done a resonator delete plus a catted VRSF downpipe installed. I also have a BMS intake installed as well. After the downpipe was installed, every time I accelerate, I can hear a buzzing/rubbing/grinding sound, heard mostly from acceleration from first to 3rd gear. It is quite annoying and happens consistently. I have had the exhaust install work checked by 2 shops, and they said that there are no leaks and dont see anything rubbing.

I also recently stumbled upon this video on youtube and will be applying this fix to see if it will fix it.

Has anyone else had a similar issue? Could this be the issue or something else entirely?

slow_f22 · 03-22-2021, 09:32 AM

Quote:

Originally Posted by gt-[r

;27358394]Hello. I have a m235i and I have done a resonator delete plus a catted VRSF downpipe installed. I also have a BMS intake installed as well. After the downpipe was installed, every time I accelerate, I can hear a buzzing/rubbing/grinding sound, heard mostly from acceleration from first to 3rd gear. It is quite annoying and happens consistently. I have had the exhaust install work checked by 2 shops, and they said that there are no leaks and dont see anything rubbing.

I also recently stumbled upon this video on youtube and will be applying this fix to see if it will fix it.

Has anyone else had a similar issue? Could this be the issue or something else entirely?

I have a 2015 with catless Downpipe and muffler bypass with the stock resonator still in and I can say on acceleration it has a good bit of drone to her in the cabin. However I do not experience anything out of the ordinary like grinding that you have described. There is a little bit of cabin shake every once in awhile when driving her on the highways

XutvJet · 03-22-2021, 12:10 PM

Something is rubbing. Engine's torque in their mounts when under load. This torquing (movement) makes the exhaust move around. There needs to be about a 1" clearance between the exhaust pipe and nearby chassis parts to compensate for this movement. Since the VRSF catted and catless downpipes don't use a bracket to support the downpipe to the engine block like the stock downpipe and most every other downpipe on the market, it's possible that the VRSF downpipe is allowing for additional exhaust movement and/or it was not built/installed correctly and it has caused a slight shift in the way the midpipe is orientated. Also, you've modified the rear of the exhaust with a resonator delete; either replacing it with a non-resonated pipe or the resonator cut out and rewelded. Either way, this modification too could have created or compounded a rubbing/contact problem. Exhaust pipes expanded and shift around slightly when they're hot as well.

Someone needs to get under the car and REALLY inspect the clearances while really moving the exhaust around on it's hangers. I'm certain there's a clearance issue in the area where the downpipe and midpipe meet or a clearance issue just forward of the rear axle. Since the VRSF downpipe doesn't have a bracket, you could loosen the front and rear V-band clamps and twist the downpipe around to see if it improves any clearance issues with the midpipe (if that's the issue).

este · 03-22-2021, 12:37 PM

Def check that emergency cable bracket he mentions in video. You can visually inspect the plastic clips that holds the e brake cable to see if it's damaged. You will need to be under the car. My car had about 75k and both brackets were basically broken. The noise for me was only during acceleration because that's when the car squats and cable hits drivetrain. I ended up zip tying cable to diff as a temp fix and noise has been gone.

03-17-2021, 04:18 PM	#1
gt-[r] Private 10 Rep 63 Posts Drives: 2013 E82 Join Date: Sep 2016 Location: Vancouver iTrader: (0)	M235i VRSF Downpipe & Res Delete Issues Hello. I have a m235i and I have done a resonator delete plus a catted VRSF downpipe installed. I also have a BMS intake installed as well. After the downpipe was installed, every time I accelerate, I can hear a buzzing/rubbing/grinding sound, heard mostly from acceleration from first to 3rd gear. It is quite annoying and happens consistently. I have had the exhaust install work checked by 2 shops, and they said that there are no leaks and dont see anything rubbing. I also recently stumbled upon this video on youtube and will be applying this fix to see if it will fix it. Has anyone else had a similar issue? Could this be the issue or something else entirely?
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03-22-2021, 12:10 PM	#3
XutvJet Major General 5552 Rep 5,369 Posts Drives: 2011 Cayman Base, 2016 M235 Join Date: Mar 2016 Location: Kansas City iTrader: (-1)	Something is rubbing. Engine's torque in their mounts when under load. This torquing (movement) makes the exhaust move around. There needs to be about a 1" clearance between the exhaust pipe and nearby chassis parts to compensate for this movement. Since the VRSF catted and catless downpipes don't use a bracket to support the downpipe to the engine block like the stock downpipe and most every other downpipe on the market, it's possible that the VRSF downpipe is allowing for additional exhaust movement and/or it was not built/installed correctly and it has caused a slight shift in the way the midpipe is orientated. Also, you've modified the rear of the exhaust with a resonator delete; either replacing it with a non-resonated pipe or the resonator cut out and rewelded. Either way, this modification too could have created or compounded a rubbing/contact problem. Exhaust pipes expanded and shift around slightly when they're hot as well. Someone needs to get under the car and REALLY inspect the clearances while really moving the exhaust around on it's hangers. I'm certain there's a clearance issue in the area where the downpipe and midpipe meet or a clearance issue just forward of the rear axle. Since the VRSF downpipe doesn't have a bracket, you could loosen the front and rear V-band clamps and twist the downpipe around to see if it improves any clearance issues with the midpipe (if that's the issue). __________________ 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. Last edited by XutvJet; 03-22-2021 at 12:16 PM..
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03-22-2021, 12:37 PM	#4
este N54 to N55 66 Rep 308 Posts Drives: e92 335i (sold) / M235i 6mt Join Date: Jul 2013 Location: Austin iTrader: (0)	Def check that emergency cable bracket he mentions in video. You can visually inspect the plastic clips that holds the e brake cable to see if it's damaged. You will need to be under the car. My car had about 75k and both brackets were basically broken. The noise for me was only during acceleration because that's when the car squats and cable hits drivetrain. I ended up zip tying cable to diff as a temp fix and noise has been gone.
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