I have a B16a in my G2. Many many many many people have asked me for advice with little problems I too ran into with the swap. I just wanted to post these tips so anyone with the same questions can get them answered more quickly that I did and maybe I’ll get a few less emails. Here goes:
SWAP PICS
http://home.apu.edu/~jkillebrew/swap.html
EXHAUST MANIFOLD (for non-obd motors)
Im using the stock exhaust manifold that came with the b16a. You can remove that center beam and it wont effect your ride at all. Might even make it a little smoother. The jdm xsi doesnt even have this beam. this method gives you 2 o2 sensors as they were originally intended.
if you want to use a dc header, you need to have the o2 sensor bungs welded onto the pipes coming out of ports 3&4 (O2 sensor 1 on port 3 and 2 on 4) and then get that other O2 bung that the header comes with closed up
Dont bother using the b18a manifold because if you have 2 o2 sensor wires on 1 o2 sensor you will waste gas and the car will feel slower. Also dont leave the sensors unplugged or the car will run lean which can be dangerous.
If none of these are an option and you have to use something with improper O2 sensor configuration, get a chip for you ecu that ignores the O2 sensors, or at least one of them, tho i dont recommend this.
INTAKE
Your b18a throttle body is the same size as the b16a throttle body considering then are both obd-0 or obd-1 engines. (obd-0 motors have 58mm and obd-1 have 60mm)
The intake manifold will not swap so use a T splitter to run the vaccum lines out of the back of the manifold to all the smog equipment and be careful you run the lines the right direction.
POWER
I didnt feel much of a loss in torque but that may have been due the fact that my old b18a was very tired (161k miles) and the new motor has VERY short gearing on the JDM s1 tranny, similar to a type r integra.
MODS
For a little more power i put in ctr cams and valve springs and AEM cam gears set to +2 intake -1 exhaust. Then I chipped the ECU for a higher redline (jdm PYR chip) and installed and APEXi VAFC to save fuel (the chip is pretty agressive) and raise the vtec point. My ignition timing is +2. With these mods I have a lot more torque in this b16a than my B18a did.
pics of my cam install are here: http://home.apu.edu/~jkillebrew/cams.html
KNOCK SENSOR
One problem I have seen a lot of people run into with this swap is wiring the knock sensor. Try not to confuse the oil temp switch wires (if you have A/C) with a knock sensor on your b18a. This green connector on the b18a should be swapped over to the b16a if you are going to keep your a/c since this helps cool the engine after the oil gets hot by running the condensor fan, expecially when using the a/c. However, you will probably have a hell of a time finding the tool to pull the plug out of the b16a to move this connector over. So remember, there is no knock sensor (white connector) on a b18a and you will need to add that connector to your existing harness just like you did with the vtec stuff for the b16a.
CLUTCH CABLE
I would also recommend fabricating a clutch cable bracket by grinding down one of the brackets from the b18a to fit on the b16a. Or you may be able to get a clutch cable bracket from a 92-93 gsr. If you dont use this bracket the clutch will feel spongy. You need to keep the cable in place.
Thats all for now.