Low boost/Leak?

evoq007 · 12-23-2011, 07:29 AM

Morning guys.

I just brought my 135 into service and after it came out I reinstalled my cobb ap. I am running Stg1 Aggressive with 93oct. Prior to service I was boosting about 14.5psi with my mods being a catback and DCI. After service (plugs, oil change, and brakes) I am only peak boosting to 12.4 and tapers to 6.5psi at higher RPM. Attached is a log. I checked the DCI and all is tight and seems to be installed in correct position. I am going to do a log at stg0 later this afternoon to see if anything has changed. Anyone have any thoughts as to why a plug change and oil service would do this?

https://docs.google.com/spreadsheet/...XM0ZnQ0TFRkMnc

Ihave1 · 12-25-2011, 09:23 AM

has the air temp changed since you were used to seeing 14.5? If you were hitting 14.5 in the summer, it will drop with the cooler, denser air in the winter. Cobb targets power/load not a specific psi. Also check the bypass valves and ic piping. Maybe something got knocked loose?

12-23-2011, 07:29 AM	#1
evoq007 First Lieutenant 71 Rep 370 Posts Drives: 2011 M3 Join Date: Oct 2010 Location: Orange County, CA iTrader: (6)	Low boost/Leak? Morning guys. I just brought my 135 into service and after it came out I reinstalled my cobb ap. I am running Stg1 Aggressive with 93oct. Prior to service I was boosting about 14.5psi with my mods being a catback and DCI. After service (plugs, oil change, and brakes) I am only peak boosting to 12.4 and tapers to 6.5psi at higher RPM. Attached is a log. I checked the DCI and all is tight and seems to be installed in correct position. I am going to do a log at stg0 later this afternoon to see if anything has changed. Anyone have any thoughts as to why a plug change and oil service would do this? https://docs.google.com/spreadsheet/...XM0ZnQ0TFRkMnc
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12-25-2011, 09:23 AM	#2
Ihave1 Private First Class 42 Rep 159 Posts Drives: 2008 135i Join Date: Jan 2011 Location: NC, USA iTrader: (1)	has the air temp changed since you were used to seeing 14.5? If you were hitting 14.5 in the summer, it will drop with the cooler, denser air in the winter. Cobb targets power/load not a specific psi. Also check the bypass valves and ic piping. Maybe something got knocked loose?
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