Which engine do i want? b20a5 or b21a1.

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which engine would u recomend? if the b20 what do i need to change my b21a1 to a b20a5 in my 91 Prelude SI?


Junior Member
I would also like to know this information. I have a 91Prelude with a blown b21A1 engine & need to replace it bad. Ca I use the B20a1 engine & if so what do I need to do to gt the job done.


New Member
The B20A is more reliable and is ready for boost.



New Member
but whats better

My personal feeling is the B20a, because you can boost it without killing your rings and it is reliable under boost when built properly.

The B21 has proven to be a good motor as well but it is way more temperamental, and needs more attention to keep it reliable. Even after a rebuild the FRM sleeves just eat thru the new rings that are replaced.

There have been other guys who relseeve the B21, but at that cost what is the point, you might as well have just picked up a B20A5 cheap at a junkyard or someone who is selling theirs.

The B20A5 came with factory sleeved iron sleeves, and are proven to handle 400+ HP. (just the block, the head will need to be strengthened)

Does that answer your question?

Oh and one more thing, dont think about going N/A build on a B20/B21 motor, the most you will get for spending $3000 will be around 150whp. Boost is the only way to pull any real power out of a B20A5 or B20A(JDM) and the B21A1 as well if you choose to boost that motor.

3GP Aftermarket Specialist.
Sean Tydingco


New Member
where can you find the neccessary kits/parts to turbo the b20a5? Im new to the honda game and would appreciate some advice.


Brutal Moderator
Eh, I suppose it's not really his fault. I told him to check out this thread and contact that 1Funryd guy...I was thinking more of a PM type thing, but oh well...at least he's in the right place... :shrug2: