O2 sensor turbo location

Hi i have link ecu in my subaru sti and would like to know where you think is the best location to put my o2 sensor for tuning since i made a custom downpipe for my rotated setup.

Unless the ECU/Sensor is rated and can be offset for exhsut back pressure, it will need to go post turbo. Also the sensor type and physical mounting locations will determine how close or far away from the turbine exit the sensor can and should be placed.

This is an exsmple of those suggestions from an AEM X-Series 4.9LSU controller.

"The location at which the sensor is installed in the vehicle's exhaust system is critical to its performance and longevity. Please review the following placement guidelines:

o 18 inches (45cm) downstream of the cylinder head's exhaust port or turbocharger

o Upstream of any catalytic converters or emission control devices

o Downstream of any turbochargers or large contributors to exhaust pressure

o As far as possible from the exhaust exit (tailpipe) to avoid scavenging fresh air in low exhaust flow conditions suchas idling

o AEM's X-Series UEGO controller is a very sensitive device and, thus, it is important to have a completely leak-freeexhaust

The bung should be welded in such a way that the installedsensor orientation is greater than ten degrees from horizontal toallow any condensation to properly drain from the sensor. Inaddition, it is recommended to avoid a completely vertical

sensor orientation to prevent overheating the sensor. Failure toheed these recommendations may result in premature sensorfailure."