My b18 is old and beat up and honestly i have no idea how many miles it has lol the previous owner of the car said it had like 65k but it looked and sounds more around 200k at least. So i was wanting to swap a b20b in its place but! I wanna keep the ls tranny if possible! Its in great condition. From my understanding all bseries are interchangeable? Any info is greatly appreciated !

 

Yes it will work, i have it myself. There is tons and tons of info online. Just search.

 

Planning on doing this swap as well. For the most part it's a straight forward swap. LS tranny will bolt up just fine.

 

You will be a 2.0 now, this requires more fuel. You will need to get a adjustable FPR and crank up the pressure.
Or, a chipped obd1 ecu with a B20b fuel map on it. You must specify what head you have (a P75 or P3R) and the year. To tell if you have a low or high compression, all high compression B20's have a knock sensor. If not, then you have a low compression. If you fail to do one of the above options you will run lean at idle and throughout the power band and risk detonation. After I did my B20 swap, I said **** it about the FPR and ECU and I ended up getting one because the car was frustrating and risky to drive.

You will also need to transfer the drivers side engine mount bracket, Power steering and A/C compressor with brackets, Crank pulley, the LS intake and exhaust manifold. If you want to pass inspection you will need to transfer the ls oil pump for the crank sensor, the b20 does not have a mount for the sensor itself.

Don't listen to what people say about the distributor, wires,alternator, it works perfect. I've personally been running this swap for >6 months now (10,000 miles) with no issues.

 

You will be a 2.0 now, this requires more fuel. You will need to get a adjustable FPR and crank up the pressure.
Or, a chipped obd1 ecu with a B20b fuel map on it. You must specify what head you have (a P75 or P3R) and the year. To tell if you have a low or high compression, all high compression B20's have a knock sensor. If not, then you have a low compression. If you fail to do one of the above options you will run lean at idle and throughout the power band and risk detonation. After I did my B20 swap, I said **** it about the FPR and ECU and I ended up getting one because the car was frustrating and risky to drive.

You will also need to transfer the drivers side engine mount bracket, Power steering and A/C compressor with brackets, Crank pulley, the LS intake and exhaust manifold. If you want to pass inspection you will need to transfer the ls oil pump for the crank sensor, the b20 does not have a mount for the sensor itself.

Don't listen to what people say about the distributor, wires,alternator, it works perfect. I've personally been running this swap for >6 months now (10,000 miles) with no issues.

 

I've done a few of these swaps. on a stock p75 ecu they run almost scary lean just shy of 14:1 from 4500-5500 rpm at wot. since the b18 makes tq higher in the rpms the mapping is off. raise the fuel pressure can bring the whole afr curve down but it will still have the same shape leanest around 5000 rpm and richer above that. I would also turn back the dist 2 degrees and or run 6 range plugs. 93 octane will help for sure but it still may detonate slightly at moderate load and low rpm on regular 87-89 octane. if u get a b20 low comp you should swap out the intake cam for a p75 cam. it will greatly help the motor not fall on its face above 6000 rpm. all the other b18 stuff bolts right up and don't foeget to swap oil pumps as mentioned. it's a good time to do tb and water pump and possibly rear and front main seals. all that is wayy easier with the motor not in the car

 

Yes a b20 will bolt up. But like everyone is saying you will need a base map for a b20 easy to find.