BB2 swap. help please - Honda Prelude Forum

BB2SiAEM · 01-17-2010, 06:36 PM

ok i dont know if you guys might know, but if you can help me then great. ok i have a '92 BB2 Si with an H23A1 and i got rod knock lastnight so im thinking of swapping the motor to another H23A1 and if not to an F20B. do you guys know what other mods im going to have to do to swap to the F20B. if you can help me out just message me thanks.

minilogoguy18 · 01-17-2010, 09:38 PM

It bolts right in, just get the ECU to run it but you'll have to wire up VTEC. Most Si's have the spool valve plug already which is a grn/yel single wire plug that is off to the side near the passenger shock tower. The other one needed is the oil pressure switch, you can either buy a aftermarket sub harness or if your motor comes with a RHD harness you can just steal the plug.

BB2SiAEM · 01-18-2010, 03:02 PM

ok so it bolts right in and everything, will i be able to use my same tranny or would i have to do a complete swap. ok so if i find the RHD harness i can just use that plug. cool.
what about a K24 from the CRV thats gonna be more work huh

minilogoguy18 · 01-18-2010, 10:04 PM

A lot more, there have only been a few K swaps into preludes, they're pretty expensive motors too. All H and F transmissions are interchangeable. You'll have to trace the wire back to the big plug that goes to the main harness, take the plug apart, remove the pin and cut the black ground wire. Plug that same pin in the only blank slot on your engine harness where it plugs into the main harness near the fuse box and ground the black wire.

BB2SiAEM · 01-19-2010, 08:12 PM

oh ok so throwing in a K is out of the question for me then haha, hmm so theyre interchangeable ok cool but idk man i found a H23A VTEC so i might through that one in instead of losing torque with the F20B, i just gotta save up atleast 1.5G's for everything cuz imma do the work myself

minilogoguy18 · 01-19-2010, 09:13 PM

The H23a VTEC is a nice motor but it's OBD2. Gonna take a lil more work to get it running and then eventually you might want to convert it to OBD1 for more tuning options, not really worth it for the 0.1 extra displacement.

BB2SiAEM · 01-19-2010, 11:35 PM

ehh i think ill just leave it as OBD2 cuz im not really looking into tunning it right now im just gonna use it as my daily driver till i get the chance to buy myself the NA MX-5 that i wanna buy then ill change change it to OBD1 and do the tunning to the H23a. but why is it gonna take a lil more to get it running is it that much different from the H23A1

minilogoguy18 · 01-20-2010, 10:47 AM

The USDM H23a1 is an OBD1 non-vtec, the JDM H23a is a OBD2 vtec.

indylude18 · 01-20-2010, 11:04 AM

Quote:

Originally Posted by minilogoguy18

All H and F transmissions are interchangeable.

That is not entirely true. Make sure you don't end up with a transmission from a type SH if you aren't using a SH block. A base tranny won't fit a SH block either.

BB2SiAEM · 01-21-2010, 01:19 AM

Quote:

Originally Posted by indylude18

That is not entirely true. Make sure you don't end up with a transmission from a type SH if you aren't using a SH block. A base tranny won't fit a SH block either.

oh ok cool thanks for correcting that for me

BB2SiAEM · 01-21-2010, 01:20 AM

oh ok so i would have to change from OBD1 to OBD2 hmmm that seems a lil complicating