Am I on crack? B18B seems like same at B20B

B20B = 147 HP and 133 ft-lbs of torque
B18B = 145 HP and 127 ft-lbs of torque
(these numbers coming from

So what’s the big deal with the B20? A little more HP and torque, but these modest increases hardly seem worth the price. Obviously the B20 is a popular swap and people seem to like it a lot, I am just trying to figure out why when the numbers seem to be so close together. I mean, I’ve seen bigger numbers from just adding a CAI.

Please educate me, as I hear the B20 bottom end is great, and am considering getting one. But I am not gonna do a block swap to gain 2 HP.

yep, i think your all on crack. I don’t put too much stock in their numbers. I remember calling HMO once and they told me that the later jdm b20b’s have a 10.2:1cr.

that said, their site claim for the jdm b20b there was…
146hp 133tq 9.6cr.

and for their jdm b18b was the…
145hp 127tq 9.4 cr.

Now i don’t know anything about the jdm b18b, but their usdm b18b specs looked right. as far as their b20 specs. Those numbers match the usdm b20z specs. I also know that at least some jdm b20b’s come with the lower cr pistons (8.8:1). So they can’t all have the same specs.

Now considering these numbers AS accurate, its possible that the b20s extra displacement is limited in the top end by using the same head designed for a 1.8L block. and yes, this engine is about low end grunt, which those peak numbers don’t really depict.

This all doesn’t excuse some of the dynos i’ve seen of b20s popping of 140whp and 135wtq with only simple bolts ons tho. Then i’ve seen some putting down wheel numbers in the low 120s


my guess is

  1. the motor is about 10 years newer- seals, rings, general wear…

  2. the numbers dont show significant peak, but i bet the torque curve has a lot more area under it. kinda like if you look at the ls vs gsr curves, the gsr gains a lot in the upper range but the ls has a higher and broader curve in the low end.
    so the b20 probably has a slightly higher but much broader curve than the b18 im assuming. now imagine a b20vtec :drool: