What the HELL is a B21

I've seen a 'B21' engine listed in some Honda books, supposably(sp?) it's the engine from a 91 prelude and it has about 2050 CCs and it's listed as a 2.1 engine. Anyone ever hear about his engine??? I've never seen one in person but maybe somone here has expierience with them :dunno:

USDM Prelude motor from the 90-91 Si, 140hp@5800 rpm
135 lb/ft @5000 rpm
2056cc
9.4:1 compression

Yeah basically those motors suck.

what engine came with the 4ws prelude? is this it?

It's the cousin to the B-series that you always hear of, but is usless crap for the most part. About the only thing that the two engiens share is the name.

In the book, it says the bore is like 1MM bigger than a GSR's, if this is true, then the block is damn good!

In the book, it says the bore is like 1MM bigger than a GSR's, if this is true, then the block is damn good!
Sorry, but ti takes a lot more than the size of the bore to make a block "damn good". The deck design, cylinder wall thickness, capcity for stroke, sleeve design, etc...just because it sayd B and is a large bore doesn't make it a good motor.

thus the term "pre-shit"

Well technically since it is a b series motor....theorhetically any b series should mount in without much hassle. Am I correct in assuming this? My friend has a 91 with 4ws and keeps bugging me about what he should do as far as motors go.

no, it's 2nd gen of Series 1 bastard B's. the head bold holes don't line up, the clylinder sleves are a alum, iron, and carbon fiber experamental material, the burn oil like a mofo after 80K on the motor hate RPM's past 6830, and needs a new timing belt every 30K. my first car was a '91 Preluse Si 2WS. The 4WS cars were B20A5, and they were the 1st gen on series one. roumer @ honda is that they are working on a third series, and it will make 275hp but it will be named the X24 with a 7 speed and put in the late 2nd-3rd gen RSX's. I think this roumer is B.S., but ya never know...ya know...

Sorry, but ti takes a lot more than the size of the bore to make a block "damn good". The deck design, cylinder wall thickness, capcity for stroke, sleeve design, etc...just because it sayd B and is a large bore doesn't make it a good motor.


If it's the same design as the B20, it's damn good to me. ;)

If it's the same design as the B20, it's damn good to me. ;)
That's the point, it IS NOT THE SAME DESIGN. As stated above the are problematic piece's of shit, they don't share anything with a newer B except the numbering system.