B21a1 (anyone Remember That One Lol)

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lafleche

Junior Member
Hey guys,
I'm a newbie to this forum. I see that there are some very knowledgeable people here, which relieves me. I've been searching for a reliable source of honda info for a couple days now, seems I finally found it. Well guys, here's my story, I hope you can help me out...
I have a '90 prelude S. SOHC, carbureted, 12 valve...the thing is a DOG at 104hp. Might be zippy, but no real power. My friend has an '89Si, running of course DOHC FI 16V at 135hp. I've been trying to get an Si engine for a while now, and I just found last week a '90 Si b21a1.. The dealer (it's a crappy little place) is selling it for 500 bucks cause it's got a blown head gasket (that's what he said his mechanic said). Now, my buddy and I are going to buy the car together, cause he wants all the paneling inside (his is tan), and I want the engine. He is a 12 month apprenticed mechanic, so he knows a bit by now about working on cars (especially 3rd gen 'ludes...he's got ALL kinds of stuff on his car, including a turbo). However, I knew him before he was a mechanic and I know he tends to do a hack job, although he knows his stuff.
So basically, my question for you guys: what exactly is involved in doing this swap from a b20a3 to a b21a1? I know it's probably the same motor mounts, but I'd like to know if:
1) My current tranny will work with an Si...I JUST got a new clutch.
2) My current exhaust will work with an Si (although I could take it off of the new one if need be)
3) My current ECU......
4) All non-motor parts, such as power steering, cruise control, etc...do I have to switch those to?

Now, I'm a newbie to this forum but not to forums in general: I KNOW to do my research before I go and post nOOb questions, but the thing is, not many people in this world care to put a b21a1 in their car. It's VERY difficult to find any info on swapping in the 3rd gen 'ludes. I really don't have the time or money to put a newer motor in there, I feel a b21a1 will suffice with some bolt ons.
Guys, I really appreciate the efforts you will hopefully put into replying to this post :p

Thanks,
Danya
Wannabe honda tuner
 
im not 100% but you are going to need more than a computer...

you are going to have to convert your whole car to fuel injection. i have no idea what that entails.... frankly, i think you are getting into a tough project, with little to no support availble on the thing you want to do.
sorry i cna't help anymore
 
Well, that's discouraging! I know I'll need more than an ecu, I'm sure I'll have to take the whole motor, perhaps the exhaust, the harness, etc...I really don't think it can be much harder than dropping a non-native motor in there. I'm sure putting an H22 or a B16 in there would be trickier than bolting in the same motor from the same car but a different trim model. I KNOW I'll have to change:
1) The engine
2) Fuel induction system
3) Computer
4) Harness
5) MAYBE exhaust...not too sure on that one.

I really hope that someone reads my drivel and can help me out, I REALLY want to learn how to do this! I think it'll be a blast...get some beers, work on the car...lol..
 
There is like no support for those older preludes I just realized. I personally think those older ludes look pretty cool and i wish there was more support for them. Everyone is about the Civic, good luck finding info.
 
damn civics...I love preludes with all my heart.

Honestly, I'm so fed up with trying to find info I think I might just fix up another ratpiece cavalier that I have so my gf can drive it, and just do that damn prelude tomorrow lol....I'm rather mechanically inclined, and I'm sure I'll have no problems with actually switching the components from one lude to the other, it's just all the SETTINGS that I'm worried about....maybe there aren't any! I don't know! That's the only thing that makes me really nervous...
 
you will probavly need to redue the entire fuel system you may need a new pump and lines for higher pressure
you will need the engine harness
if you are getting the donnar car then you will be in good shape
get a hanes manual and run all the wireing first that is the hardest part
 
thanks for the info man! Anyone else got some pointers? Looks like I'm buying it next friday....how long do u guys think it would take an amateur mechanic and myself to throw it in? A week? Two weeks? A day?
 
Buy the engine, and just take all the EFI components off it. Swap all your carbed stuff on and eventually buy a dual weber set up. As far as no support that is BS. You are on the wrong kind of forum to find support for this car. I do not know of any specific 3rd gen Lude sites, but I know there are a couple of 3g ludes on www.3geez.com
 
get a wire diagram for your car and swap
i can email to you if you need tham let me know
 
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