Been looking on Hmotors trying to decide on an engine.
What im getting caught on is I hear more people doing b20b swaps but the specs on the b18b look similar if not better.
from Hmotors:
b18b - 145Hp 127Trq 9.4 Compression (JDM)
b20b - 126Hp 133Trq 8.8 Compression(JDM)
almost a 20 hp difference but only 6trq difference. Plus from what i have read the b20 chamber walls are a little weeker then the b18 because it is pretty much a bored b18.
So why would somone go B20 for less Hp and only 6 more trq?
Also what are the specs on the b20z and were did those come from? Just usdm Crv’s?
Any help would be great because i am leaning towards an Auto b18b for the old lady’s car. With a few mods in the future.
Thanks
Chris
Those specs on that b18b do not seem correct.
I know its 140hp, and I’m sure on the torque.
People get the B20B generally with plans of upgrading before installing. The extra displacement reacts better to mods.
i don’t know what you’re reading, but try fact instead of fiction for a change.
the b20 is NOT pretty much a bored b18. the cylinder sleeve design is COMPLETELY different. the block is altogether nowhere near what a b18 block is. however, as far as “weakness” goes, that’s up to what your application will be. if you’re boosting, it won’t do well past 5 or 6 psi. if you’re staying n/a, i know of 3 or 4 people offhand who are making 230-240 whp normally aspirated with a stock b20 block (no aftermarket sleeving), 84.5mm bore.
i was thinking the same too, but more of just to replace my block because it leaks and burns oil. would a b20 be good if i used my b18 head? or should i just go with a b18b longblock
Dont go by those b20b’s #'s becuase the b20b with its stock restrictive manifolds (partically the exhaust manifold) are crap. Swapping over everything over from the LS to the b20 will help for sure. I would say it would average around 140hp with the ls manifolds. If you want more out of the b20, port & polish the head and put some crower valvetrain in there and run some crower 403-404 cams.
I vote b20 if you plan to stay away from boost. Im currently building a all-motor b20b, its turning out very well and i dont even have cams in yet.
cool so you recommend the b20. guess ill go for that because i will use all my ls stuff for the b20
Sorry that was supposed to be a question. But hey thanks for the fact or fiction lesson. I will remeber for the future not to ask a question unless i know the answer first so that I stay factual.
Also thanks for the info everyone.
Chris
b20b > b18b any day of the week. put some b16 gears on the b20 with a little dash of lsd, and you got yourself some high 14s - low 15s with basic bolt-ons.
B20! Those numbers that you provided dont seem correct either…but I can easily beat any b18 with basic IHE…And mine is completly stock…Im sure with a few mods mine would give a stock GSR a run for its money.
Also the walls being thicker are only an issue if you are looking to rev the piss out of the thing or boost it. There are also b20z’s that come with i belive a 9.2:1 comp. ratio. There hard to dfind but you may want to look into that.
I think the B20Z was 9.6:1 compression. B20B (usdm) was 8.8:1. IIRC all JDM B20s are B20Bs, but some are the high compression version. The specs he listed for the B20B are about correct, the B20Z has 146 hp in the CRV.
Are the external dimensions of the B20 block larger than a B18? I was under the impression that it was the same basic block casting, with different sleeves.
Thanks for the replys, I never said those numbers were correct i just cut and pasted that from the Hmotors site.
I wasnt blaming you, i was blaming your source
from what i understand all b20b/z from 97-98 have the lower CR, the higher CR b20s were not made til 99, someone plz correct me if im wrong.
that is how I understand it as well. AFAIK, all B20s before 99 were B20Bs, with the 8.8:1 compression. 99+ B20s in the US were the B20z with 9.6:1 compression, they were still called B20Bs in Japan, but can be identified by the knock sensor and low-rise intake manifold.
heres the low down
B20Bs are from 96-98
they have 126hp and 133 ft lbs. rated by honda which means its with the stock CRV manifolds. so if you use your LS manifolds, youll see a gain in power, simply because they flow better
8.8 CR
B20Zs are from 99-01
they have 146hp and 133 ft lbs. again, rated by honda.
9.6 CR
i would follow integracers suggestion… wait… i already am 
some jdm b20b’s have a 9.2:1 cr, supposedly by way of a 2 layer head gasket. If you get a jdm one, at least try for one with the low rise intake manifold (b18b style), it’ll flow better than your g2 intake mani.
Also, there’s more to compare than just peak power numbers. Don’t forget about the “area under the curve”. A broader powerband in the b20 makes it so much more drivable; well suited for the ls tranny imo.
d
is the b20z only in the US?? also, if you put on the b18 manny in the z like in th b20b will it gain power, or is the z’s already good?
the Z designation was only used in the US, the same motor was available in Japan but still called a B20B. I think some people have used the low-rise B20 manifold and just plugged the hole to the extra chamber.
My Engine
STOCK B20B Short Block
PnP B20 Head
Crower 62403’s
Crower DVS’
Custom IM
JDM ITR Header
All will be installed soon.
I vote B20 over the LS.
Tell us how it turns out.