JDM Primera Downpipe

[Steve Obert]

The factory cast manifold has a crossover in the manifold between the 2 down
pipes so the sensor sees all 4 cylinders.  I noticed that aftermarket
headers have it located in one of the down pipes.  That is what I will
probably do and mount it as high as possible.

> Doesn't the HS O2 sensor bung read only one cylinder anyway?  Just put the
> bung in your leanest (hottest) cylinder's primary, at a factory-like
> distance from the port, and call it a day.