there is no difference between the two except for small stuff like FITV/IACV, o2 sensors. there is no need at all to switch to an obd2 ecu. period. if you want to upgrade your ecu, i'd upgrade to an obd1 if anything that way if you decide to build your car at all (not sure if you're into that at all), it will be better for tuning and stuff like that. just because you have a 97 engine in a 91 does NOT mean you have to run that ecu as well. all you are doing is putting a newer non vtec b18 into an older chassis. it will not run like crap unless you got a junked engine or don't know what you are doing. use your current pr4 that you have and you will have no worries.to run the 97 ecu? why is there a difference on bhp between the b18a and b18b?
yessir just get a obd0 to obd1 conversion harness along with a obd1 ecu (p 74 or 75). then you can chip it and tune it better. plus mods respond much better to obd1 vehicles. the difference in horsepower was due to the change in the cams used between the heads. the intake and exhaust manifolds also played a small, small factor in it as well.To upgrade to OBD1 I just need the conversion harness? Anything else? and do you know why there is a 12 hp difference between the 2 engines?
no you don't. unless you want to get those. thats the whole purpose of having a conversion harness.... to convert. your car will run the same with the conversion harness or not. the conversion harness is also the cheaper route so you don't have to go and buy an engine harness. hell my car is orignally obd2a and i converted to obd1 when i did my ls/vtec swap. still using the odb2 gsr dizzy. no problems here what-so-ever.but i also need an OBD1 dizzy and 4 wire O2 sensor also correct?