BS1 head to A20A3

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03-13-2004, 12:18 AM
Not like a rock

BS1 head to A20A3

I have a rebuilt BS1 head (from the 86 EXi). Can I use this to replace an A20A3 head? The A20A3 is rated at about 10hp more than the BS1, so will the new combination be 10hp less with a functioning A20?

This is assuming that nothing else is screwed.

Thanks to anyone who might know.
03-13-2004, 07:04 AM
carotman

Yeah the heads are the same. The 10 HP didn't come from the head itself.
03-15-2004, 10:45 AM
Not like a rock

Where did the power come from? If I want to put my A20A3 in an 87 with A20A1, how much do I need to replace?

The reason I ask is because I'm thinking of buying an immaculate 1987 5-spd exi, and I have an a spare A20A3 that needs the head rebuilt. So I would want to put the A20A3 and ecu in the 'new' car.

I also have a rebuilt BS1 head that could go on the A20A3.

So, to get 120hp, I need the A20A3 block, any 3G head, and the A20A3 intake manifold and throttle body? Or can I use the A20A1 throttle body? The A20A3 one is really dirty.
03-16-2004, 05:47 PM
toastyghost

I think those 10 horse came from slightly higher compression ratio but you might want to check that since I'm not 100% sure.

If you're putting the A20A3 in a carbed car, you will need more than just the things you mentioned since it is an injected motor. Check out carotman's web page for good info on EFI conversion (that's what he did to his car).
03-17-2004, 04:25 AM
shepherd79

the 10 extra horse power came from combination of head, pistons and rods. if you go to honda dealer website (like majestic) you will find that there are 2 or 3 versions of pistons, heads and rods.
plus the extra power came from new style dual stage intake manifold which had vacuum secondary.
03-17-2004, 05:40 AM
carotman

THe 88-89 has a 4-2-1 manifold style that might also help.
03-17-2004, 01:14 PM
Not like a rock

Well, I guess I'll just put the whole engine in. I thought there may be a way to get the extra 10hp without swapping everything. But if it was easy, I guess everyone would be doing it.
03-18-2004, 07:48 PM
2ndgenludedude1986

Quote:

Originally Posted by carotman

THe 88-89 has a 4-2-1 manifold style that might also help.

im kind of mad i threw out m y 89 exhaustmanifold, i woudl of lieked to put that on my lude insted of the shitty one that come on the 1.8. but even so i dont believe there would of been that much differance. anyone kno what the exhaust amnifodl was on a 86 a18?