B21A

[Dat91preludeSiR]

i have a stock B21A motor in my 91prelude SiR can anyone tell me is it good and keep it or swap with something better?

[Bill]

i would swap it cuz that motor and the other b20 that came in those ludes arent considered part of the b series family lol

[Dat91preludeSiR]

Originally Posted by Bill

i would swap it cuz that motor and the other b20 that came in those ludes arent considered part of the b series family lol

oh and what should i swap it for?

[Bill]

either a gsr or a crv b20

[Rosko]

Originally Posted by Bill

either a gsr or a crv b20

Neither of which drop right in to my knowledge, since as you said those B's are a whole different animal. Theres mount kits out for an H series tho. Check out preludepower.com they are the largest 3rd gen Prelude site out there and theres tons of info about swaps etc. on there.

[MJobe]

95mm Cranks in those if I remember correctly, Lots of old drag guys would balance and use those before eagle etc released them.

[Ej6kev]

i say go with a b20

[honda2k9]

you should just swapp it out with an h22a, because b21's are really weak. they cant take abuse like the other b series motors. h23,h22a, or a b18 are good swapps

[90preludeLad]

since this thread has a ton of misinformation in it, i'll clear soem things up.

i'll take it you mean b21a1? the b21a only came in the 90-91 jdm prelude si states, which i highly doubt you own.

the b20a, f22, h22, and h23 are the only motors that can go in 3rd gen ludes. the gsr or b20b will not work and there is only 1 person out there who has made custom mounts for a 3rd gen to run a gsr motor. once it was in he ran into shift linkage clearence problems.

and as for the b21 being a weak motor and not being able to handle abuse, thats not true at all. there are a few guys running 75 shots on them for 3-4 years now with no problems. and as far as boost in concerned, the headgasket is the weakest part, and since no one makes headgaskets for us, 250 whp is about as far as you can go without risking blowing one. once this group buy happens for mls head gaskets, guys should be pushing higher numbers yet on stock internals before the rings give out due to the frm sleeves, but saying the motor itself is weak is ignorant.

and listen to rosko, go to preludepower.com for any questions regarding 3rd gens, as 95% of the honda owners on other forums don't know much about them.

And to add to ^^^^

This engine has huge tendencies for the sleeves(FRM) to literally eat the rings, therefor the older your B21a1 the more its gonna smoke. Not just a little, but sometime a lot! This engine puts down some good TQ, and is quite reliable.

As far as the SI States edition Prelude... Like stated good luck, That car outperformed the Corvette in 1991 solom course's because of its 4WS and great drivability.

My first project car was a 91 Prelude, Loved it. But very hard to find parts compared to a Civic/Integra.

[90preludeLad]

it outperformed ferraris and lambos as well. makes me smile to see a honda whoop up on some supercars, lol.

and yeah, they have a tendency to smoke and burn oil because of the rings, but if you can find one like mine with lower miles and is healthy, they are very fun, tourqey little motors. pair this with the low gearing makes these cars a blast to drive through corners. 4ws just takes the cake if you have it, lol.

[boosted712]

go with a b20 hella fast man i got a jdm b20b in my car on 5 psi and talk about lots of low end power

[H22APWRD94]

The B20A series and B21A series in the 88-91 3rd gen preludes are almost an F series motor. They tilt back like an F and H series, with the starter on the forward part of the tranny like the F and H. They even have balance shafts like an F and H. Basically like the man with the blue 3rd gen said, put an H in it or keep it stock. The B series answers mean zilch. It is near impossible.

Mike

[mr.carr]

jdm h23 vtec that shit

[90preludeLad]

Originally Posted by h22apwrd94

The B20A series and B21A series in the 88-91 3rd gen preludes are almost an F series motor. They tilt back like an F and H series, with the starter on the forward part of the tranny like the F and H. They even have balance shafts like an F and H. Basically like the man with the blue 3rd gen said, put an H in it or keep it stock. The B series answers mean zilch. It is near impossible.

Mike

well put. if your are truly serious about staying with OUR b-series, certain things like h23 rods can be machined to fit, and b18x tb and tintake manifold can be made to fit as well, i'm unsure of which one tho, guy named motoxxxman did it. just gotta search around preludepower.com, everything you could ever want to know about our cars is there.

Originally Posted by boosted712

go with a b20 hella fast man i got a jdm b20b in my car on 5 psi and talk about lots of low end power

b20a =/= b20b in the slightest....