I would just go closer to the collector, the 18" is the the max from the collector I would get it closer to the collector. The farther from the engine the less heat you get. The O2 needs heat to work.
You know what... I'm glad I went back and read the instructions...lol
It says "exhaust port" not "collector" like I mentioned. I have a wideband on my truck but the exhaust is laid out difference and there was no guessing.
"A weld-in M18 X 1.5 boss is supplied for sensor installation. Mount the O2 sensor in the exhaust system at least 18 inches downstream from the exhaust port. If you anticipate high EGT's (over 800C), run a turbocharger, run at high RPM for extended periods of time or plan on running leaded race fuel then you must mount the sensor at least 36 inches or more downstream of the exhaust port as all of these can cause the sensor to overheat. On turbocharged engines the UEGO sensor must be installed after the turbo charger, if not, the pressure differential will greatly affect the accuracy of the unit. For accurate readings, the sensor must be mounted before catalytic converters and/or auxiliary air pumps. To prevent collection of liquids between the sensor housing and sensor element during the cold start phase, the installation angle should be inclined at least 10° from horizontal with the electrical connection upwards, see below. (Figure 8)"
I believe on my car I can squeeze in the o2 sensor between the collector and X-pipe... this is what I really need to do.
