which valve controls which turbo

dr_dirtg · 06-26-2015, 10:15 AM

My boost is building to about 15psi instantly, then there is a hiccup and after a couple moments it continues to build but slowly and maxes at 25psi.

Something is definetely broken or on its.way. I bought one turbo control valve, but not sure which one to swap out?
I would think the valve which controls the bigger turbo? Is that the one closer.to the front of vehicle or rear?

sukutash · 06-26-2015, 10:28 AM

I can answer which turbo is the larger for you. Its the lower, aft turbo, the one you cant see clearly.

DWR · 06-26-2015, 04:13 PM

The situation you are describing may not fit your diagnosis. I would suggest you check the hose lines before you start swapping out electrical components. BTW, the interaction of the HP and LP turbo is controlled by 2 different types of valves (PWM and on/off). LP turbo (big) boost is clearly being controlled on the top end, so you can elimination that valve as a culprit.

06-26-2015, 10:15 AM	#1
dr_dirtg Private First Class 40 Rep 167 Posts Drives: 335d Join Date: Jul 2013 Location: Canada iTrader: (0)	which valve controls which turbo My boost is building to about 15psi instantly, then there is a hiccup and after a couple moments it continues to build but slowly and maxes at 25psi. Something is definetely broken or on its.way. I bought one turbo control valve, but not sure which one to swap out? I would think the valve which controls the bigger turbo? Is that the one closer.to the front of vehicle or rear?
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06-26-2015, 10:28 AM	#2
sukutash First Lieutenant 66 Rep 375 Posts Drives: 2011 335d, 2020 M2C Join Date: Jan 2011 Location: Ft Worth iTrader: (7) Garage List 2020 BMW M2 KOMP [0.00] 2014 BMW 535i [0.00] 2012 MERC E63 AMG W ... [0.00] 2011 BMW 335d [0.00]	I can answer which turbo is the larger for you. Its the lower, aft turbo, the one you cant see clearly.
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06-26-2015, 04:13 PM	#3
DWR Banned 799 Rep 1,630 Posts Drives: 2009 335d Join Date: Oct 2014 Location: Maine iTrader: (0)	The situation you are describing may not fit your diagnosis. I would suggest you check the hose lines before you start swapping out electrical components. BTW, the interaction of the HP and LP turbo is controlled by 2 different types of valves (PWM and on/off). LP turbo (big) boost is clearly being controlled on the top end, so you can elimination that valve as a culprit.
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