Honda put two O2 sensors on there for a reason. The ECU is programmed to use both readings for an equation to determine certain things. If you tee the O2 signals together before the ECU, all your doing is giving it two identical variables to use in it's A\F equations and stuff.
In this case, since you have only one bung in your header, teeing them together and tricking the ECU would be better than not giving it that data at all. Just remember, sensors like your O2 are important to the engine, the ECU and how well your car runs. People like to "delete" a lot of "unnecessary stuff" from their engine bays and cars and do tend to remove stuff that does serve a legitimate purpose for the function of your engine. Charcoal canisters you can get rid of, and purge evap valves, etc... as long as you route the rest of your vacuum properly, and don't accidentaly delete your MAP sensor as well.
The best thing to do is know what your touching before you touch it, lol
Oh, on the radiator issue. When I did my first B16A swap into a CRX, it was going into my 88 Si. I bought a 90-93 Integra LS radiator and fan with the swap and used fully B-Series hoses without any issue. I believe the cooling surface area is far greater as I think it's dual core, OEM style. With a stock thermostat, stock hoses, Honda Genuine coolant, and a new water pump, I never hit operating temp and my fan never once turned on. There's an optimal cooler temperature that's just underneath (with how "precise" our OE water gauges are) operating temp that's hot enough for VTEC to work, but cool enough for better performance. I once moved so much air through that front bumper ( doin like a buck +, COLD night mind you) that the water temperature dropped enough while I was in VTEC to kick out of it and go into safe mode fast enough to hit me in the face with the 7200rpm rev limiter.
That bitch NEVER let my engine sweat, not even for a minute. HONDA FACTORY baby
ALSO, make sure you remove those little dust sleeve ring mother fuckers from the INSIDE of the steering knuckles, right on the opposite side of the wheel bearing, where the axle actually pokes through the knuckle. It's a thin little ring on the interior diameter of the backside of the knuckle. Get some needle noses, put a glove on (I would've loved to have one on when I first pulled one out.. major knuckle buster) if you want to, and grab a hold of the edge of it and pull it out of the knuckles on both sides. This allows proper fitment of your axles. If you don't, the fit sucks and things happen to your axles, like if you forget to pull them out like me and when you fasten the spindle nut the ring becomes a "spacer" and the tightenting of the lock nut pulls the end of the axle out of the tranny ends axle housing and tears the boot too... ugh
ALSO, One big issue for this swap is the axle most people choose to use for this swap. A lot of people swear by 90-91 LS axles and other ones you can buy that are "custom". The LS axles are too long and cause binding issues, which is why swappers break so many of them. Auto Zone no longer even remanufactures ANY Honda axles (or maybe any axles they even sell anymore) due to the large volume of Honda replacements done annualy. It's actually cheaper to replace warranty axles with a new pair each time than it is to fix old ones.
The 88-89 Integra LS axles ARE THE BEST AXLES TO USE.
Your CRX is NOT AN EF CHASSIS CAR.
It is an ED CHASSIS, LOOK AT YOUR VIN NUMBER!
People forget this often times when talking about swaps and compatibility.
The engine you just bought came from an EF in Japan, and the axles are suited to that chassis width. 90-91 Integra chassis have the code DA, which means likely a different width than preceding years. Those are actually wider.
BUT, you can't use the B16 axles because the knuckles aren't the same as your ED chassis knuckles, so the spline count's different and the width is still about an inch wider ( to allow for the B16A alternator to clear.. on ED chassis cars here, you have to dent that spot on the frame rail in, or cut it out or whatever to clear the alternator pulley). HOWEVER, the CLOSEST USDM representation of your chassis\swap setup is the 88-89 Integra which is ACTUALLY AN EF chassis IN AMERICA. The chassis is smaller, so the knuckles are similar in size to ours, and the spline count is the same, but it's got the correct axle width, and the tranny ends fit into B-Series engines...??!?
So basically, do yourself a favor and go to Auto Zone or Pep Boys or Advance, and get those year LS axles and the warranty on em. Fresh axles for your swap will be nice. Or you could junk yard em, or buy em on the internet. But NEW always feels good too.
You really should consider changing your suspension if you haven't. You need spring rates to compensate for the new weight in the front end, it IS heavier now.
The car will not handle as nimbly as it once did, buying a suspension designed for a swap in your chassis with your specific engine will not only improve your overall handling, but it will compensate well for the weight change upfront, making your car faster in many respects.
Also, things like alignments after a swap, brake bleeds during or after, tire rotations, bulb\fuse checks, lots of other basic issues can be handled while the cars down to help limit the amount of post swap issues. You wouldn't believe how many thousands of posts on the internet talk about how their car or their new engine was working just fine "BEFORE the swap" and "NOW IT WONT FIREzOMZG!!1!one!"
Remember, you are not only pulling it's engine out, but shoving something new in there. Not only that it's heavier and it's going to put a lot more stress on your car with that much more power, and stiffer mounts, your car in general needs to be set up to handle it, just consider the current setup of your car and figure out what you should change to compensate\improve overall performance
