Legacy O2 Sensor Questions

[Dharma_Bum]

I am starting a 2.2l engine conversion into a Vanagon. I have a NOS 90-91 2.2l engine. The wiring harness and electronics came out of a '91 non-turbo Legacy donor w/ 278k miles on the odometer. I did not get the Subaru Catalytic Converter (CAT) or the Subaru Oxygen Sensor from the donor car. I have purchased an aftermarket Catalytic Converter from Small Car Performance designed to work with the Subaru engine. The CAT has the port drilled and threaded to mount an Oxygen Sensor in the CAT.

 

I have been looking at Subaru Oxygen Sensors on the internet and there

seems to be a wide variety of brands and prices. Prices range from

about $30 to $95 dollars and the most common brands seem to be

a Bosch ($82) and a Denso ($95).

 

Questions:

 

-- Are all Oxygen Sensors created equal? Is the Denso (OEM?) worth the extra cost?

 

-- Many of the Oxygen Sensors are advertised as "Connector BEFORE

Catalyst". Will these sensors work for my application - directly into

the CAT?

 

-- Anyone have a favorite on-line vendor in the USA for the Subaru

specific parts like this? This will be my first Subaru part purchase.

 

Thanks!

[porcupine73]

Sounds like a cool project!

I'd go OE for a couple reasons. First is I've seen many recommendations to use OE for the front oxygen sensor on this board. Second is then you know the connector will fit without any extra work on your part wheras aftermarket are sometimes a 'generic' where you cut the connector off the old sensor and wire it onto the new sensor.

 

The sensors labelled as 'before cat' ('front sensor') is the one used for A/F ratio adjustment; the 'after cat' / rear is typically used to determine catalyst efficiency.

[nipper]

subarus have two sensors, one before the cat that talks to the computer, and the one after to make sure the cat is working. the first one should be a OE o2 sensor, the 2nd it doesnt matter.

 

The cat is too hot for o2 sensors... give snall car a call and see what they suggest.

 

nipper

[Dharma_Bum]

I think the '90-'94 OBDI Legacy's only had one O2 Sensor. Later models had two. I am only planning on putting in one sensor directly in the CAT... but I need to make sure I get the correct one.

 

Is the Denso the Subaru original O2 sensor?

 

Thanks for the reply.

[nipper]

nipendenso most likely is

 

nipper

[Manarius]

NipponDenso is OEM spec. And, 90-94 only had one O2 sensor - stuck right in the Y merge.

[NorthWet]

I have been told by parts counter persons that many/most/all Bosch direct-fits for Subarus are repackaged NDs... the sensor has ND logo on them.