Installing a B Series Intake on the B20A

Since I had a B16A2 manifold around, I thought I'd try installing it on my prelude, just to see what it would do. This isnt the cleanest install since the main purpose was to see how it would work out. So bare with me.

For the first steps, you can get by with some very basic tools as illustrated.
Mark up the B16 flange with an old A20 / B20 gasket


Mark up the B16 flange with an old A20 / B20 gasket



Drill out the new stud holes, and saw off the water jackets. The top right hole (on the picture) will need to be enlarged a tad bit.
If you have a B20A/1/2/8 you need to remove some material from the top center hole, otherwise the flange will hit the head.

In my case I decided not to use the stud located at the old water jackets, and not to put a nut on the center stud, since it would be too much trouble.


 The sawed off water jackets.


If youre going to grind something, then you cant live without these babies. Really agressive grinding bits. I used a battery drill to keep down the rpms to avoid getting aluminium stuck in the grinding bit, but you can use an air powered grinder as well.


To be able to tighten down the manifold you need to make place for the nuts. In the 2 areas I marked I grinded off some material.


Here you can see how much material you have to work with. Dont grind all the way through the runner...

I also cleaned up the flange. 


You need to make an extension bracket for the throttle cable in order for it to reach the throttle. The bracket needs to be about 14cm long. I made mine with a small bit of adjustability.


I polished the fuel rail and the whatyoucallit stripes on top of the plenum... Get's real shiney lol

When you're done remember to clean out the manifold to avoid sucking any small pieces of aluminium in to the engine. I used some degreaser.
Afterwards you can lube up the throttle body to avoid any "sticking" of the butterfly.



To install you just need some different sized hoses, some hose clamps and some hose T'ings, and then connect the vacuum lines and water lines again. In my case there were 2 vacuum lines from the black box that had to be plugged.
You need to use your old fuel line hose for the fuel rail. I also used the old PCV valve.



 With an '86-'87 ('86-'89 european) you'll have to use your old intake temperature sensor. The IAC valve you wont be using. You'll have to get an '88- TPS sensor plug and solder it together with the harness end of an '86-'87 TPS sensor connector. This way you'll be able to just plug in the new type of TPS to your old harness.

I installed new seals for the injectors in the manifold flange and the two seals located on the injectors. You might not have to replace these, but there's a good chance that some of them might need replacing.
I reused the old head flange gasket, I just sprayed on some gasket sealing spray. You might want to keep a new gasket handy though.
I installed a new TB gasket simply because it wasnt there when I got the manifold, but often you can reuse the old TB gasket if you disassemble the TB from the manifold.

The engine is running smooth with the new manifold.

This howto was taken from