I'm in the process of dropping a B16A1 into an 89 CRX Si. I bought the wiring adapter kit from HASport, which includes a wire for the second O2 sensor. Now the questions:
My engine only came with half a header, so rather than buy just the bottom half, I purchased a DC Sports 4-1 1 piece for a 94-97 del Sol VTEC (did I at least get that part right?) Nearest I can tell, the header has 1 hole for a sensor. I initially thought the other sensor went after the cat, but now that doesn't seem right... I'm reading about a sensor for a pair of cylinders.

So.... do I need to tap 2 holes for sensors? Or can I just use the 1 sensor hole with 1 sensor and wire it to both pins? Which sensors should I buy? Universal? Brands?

Thanks.

 

You are either going to need to install 2 O2 bungs in the primaries or get your ecu chipped to disable the secondary o2 sensor. 1-4 together and 2-3 together for o2 sensors. The problem with chipping is now you have a High performance chip is most cases that does away with alot of extra stuff like VTEC oil pressure, VSS, secondary O2 and you are going to go have to live with horrid MPG. I have seen the two o2 signals wired together and it is not good, it is ghetto as hell, runs like garbage, very rich. Do it up right in either of the first two ways, if you want a good OEM(what Honda uses) o2 sensor consult your local International automotive parts store and if you can't fine one then go to Nopi online I think that they sell NTK o2 sensors. NTK is basically another division of the company that makes NGK sparkplugs so you know they are good. They will last forever ublike Bosch, CRAPA I mean NAPA Echlin. I wore 3 NAPA ECHLINS out in 6 months, got my money back, installed a used 10 year old OEM NTK back in and it has been running fine for the last 3 years.

 

Go OEM Honda on the sensors for quality/longevity, and I'd run both sensors if passing emissions is an issue for you. Then again I failed emissions, threw in a Bosch 4 wire universal and it passed with flying colors. As far as the longevity of the Bosch who knows, its only been 4 months.

 

NTK=OEM Honda cheaper than Hondas pricing too if you get them from another parts store.

 

OK, I finally got around to taking off the heat shield and actually looking at what i've got (it's been 35 degrees here the past week, so I've been procrastinating on a lot of things.) So the original header was a 4-2-1 design, with an O2 sensor for cylinders 2 and 3 and another for 1 and 4.

I figure I can just reuse the sensors that are already in there (should be OEM honda and good for 100k miles, right?). Then I just need to have a shop tap 2 holes in my DC sports header, in cylinders 1 and 2, presumably. Correct?