Ok, I'm new to this civic stuff. Can anybody tell me what the difference is between the D15B1 and the D15B2 engines. The B1 is only rated at 70hp, while the B2 is rated at 92hp. I have 2 civics, one is an 89 with the B2 and a 5 speed and one is a 91 with the B1 and a four speed. They don't feel that dramatically different in power and from what I can tell both motors are physically identical. (both 16 valve, same size, same compression ratio). What gives the extra 22hp? Can I just swap to a B2 ECU ??

Thanks!

 

could be the stroke, size of ports

 

checked - bore and stroke are the same, compression ratio is the same. Intake manifold etc looks the same... I was thinking maybe the cam is different but I was hoping that somebody would know for sure.

 

cam is different, ecu is different.

 

Ok then, I have a spare cam and ECU from a 88 B2 engine (although the car was an auto). So if I swap them in then, bam - I'm up to 92hp? I like the sound of that!

 

The cams are actually the same as well, but there are several subtle differences that give the B2 that extra 20 or so hp.

1) Different ECUs = different fuel maps
2) The B1 has a restrictor plate in the intake that only lets it open about 3/4 of the way, while the B2's can open fully.
3) The throttle bodies are different

 

hmmmmn must have been the fact that the 2 cams i measured were from different milaged motors....although it was a fairly large difference between the 2. didnt know about the tb being different.