okay so i was planning on building a engine for turbo around 12 psi, and i was wondering if i should stick with my B18a1 or go B20z or B18c1 and i was wondering what i could swap over wireing wise from the b18 to the b20z to keep the wireing down what would be the best swap for high hp+tq goals and reliability. how hard would the obd2 b20z swap be into a obd0 car?
therse a couple ways like you could keep your original harness and run the b20z as obd0 just with a lil more displacement… Your going to need to run a chipped ecu to help with the extra fuel your going to need.
If you have the b20z obd2 harness then you could splice the new engines obd2 sensores onto the obd0 harness, just run your old obd0 distributore. if you ever plan on going vtec then you can still keep the cost down and reliability. Just get a obd0 vtec ecu, chip it and then run separate wire for the vtec. thats how Im running my setup.
I have a 00 obd2 vtec engine complete with harness, disstributor, intake mani, t/b and all sensors, I didnt want to buy any jumper kits to convert from obd0 to obd1 or 2. I ended up cutting off all the obd2 plugs and connecting them to my obd0 harness to have my stock harness on the obd2 engine, then I source out a obd0 b16 vtec distributore and ecu.
so in simple words you can do it by just useing your stock ls intake manifold and distributore, or cut off all your obd0 sensore plugs of your engine harness and splice on the obd2 plugs to keep the b20z sensores and intake manifold. you will have to keep your obd0 distributore.
thanks this is a lot of help i was wondering if i could interchange the intake and distributor, did all of the plugs just wire right up or was their ant extra wires or lack of when you swapped out all of the plugs?
I went out and measured it once and this kind of stuff is 5 billion times easier to figure out with a factory service manual. 
Most of the ‘dumb’ sensors should have the same number of wires and operate the same as the OBD0 counterpart - but I have no personal experience with the wiring of sensors on OBD2 stuff so this is just conjecture on my part.
hmm this makes me kind of curiouse to try and see hoow it goes
yes all plugs on the harness have the same number of wires, Its kinda like replacing the old plugs for newer ones so you just cut them off and connect. just make sure you soder and heat wrap the wires for the new plugs and you measure them to avoid having short wires that dont reach the sensores… I think the sensores on the t/b have to be extended so take your time and do one by one. Oh and when its all done get a fuel pressure regulatore to help get more fuel for the bigger block. then chip your ls ecu if you add bigger t/b or skunk2 intake maniflod and headers.
well thats cool i figured it would be diff could i use a b20b obd1 ecu to convert it to obd1? so i can get it tuned?
yeah you can even use the stock obd1 LS ecu to run it and get it tuned… the b20 and b18a1 are pretty much the same in dimentions but the b20 has bigger 84mm or 85mm pistons than the LS 81mm. The head and valve train is also the same so in other word the b20 is a bored/stroked LS.
If you do go obd1 then your going to need the LS obd1 distributore, injectores and intake manifold
I was planning on getting a skunk2 intake for it i also have DSM injectors for it im going to build it for boost b4 i put it in do you know what all i would need to do to get the injectors to fit? because i have read they will take some moding. and do you know if b18 rods will go in the b18 because i have some eagle hbeams for a b18 it would be nice if they would work lol, sorry for all the questions.