B23/B320 Manifold Conversion For B21FTi Motors Page 1

B23/B230 Intake Manifold Conversion For B21FTi
By Stu Spencer

This page is intended to help guide you through the preparation of a B23/B230 intake manifold for your B21FTi. Because of the configuration of the inlet of the B23/B230 manifold, you MUST have a intercooler for this setup to work. This conversion assumes that you will be using the original fuel injection system on your 240 and not converting to EFI. This conversion also uses the B23/B230 throttle body instead of using the B21FT throttle body. The B23/B230 intake manifold is a more efficient and free flowing manifold than the B21FT. It has better tuned and sized runners, and a large plenum compared to the flat runners of the B21FT.

Anytime you work on your car's fuel system or electrical system it is recommended to disconnected the battery and relieve the fuel system's pressure (look in your manual)

DISCLAIMER: As always, any modification you choose to do on your car is your choice, for better or worse.

Just click on a photo if you want a bigger view.

Parts Needed

From B23/B230 manifold:

NOTE: The manifold and TB are essentially the same for all B23/B230 motors. You don't have to get a manifold off a turbo model. The throttle body bore is the same for all these motors. Volvo used the same TB size on all 'red' engines; 55mm from '76-'95. You might actually get a normally aspirated intake manifold cheaper because it is not from a 'turbo' car.

manifold
throttle spool (need double spool if you have cruise control, single spool is shown)
bracket for throttle cable (has throttle and kick down)
bracket for cruise control cable (if needed)
throttle body (complete with TPS and linkage)
throttle cable
electrical plug and leads for throttle position switch (TPS)
manifold to engine block bracket
IC to TB metal tubing, rubber IC connector, rubber TB elbow, and clamps. (these will need to be from a B23FTi or B230FTi)

This is what the manifold looks like right off the car.

From B21FT manifold:

cold start injector and mounting screws
block off plate with tube for Constant Idle System (CIS) from TB
CIS idle speed motor and bracket
original CIS tubing

From B21F car:

CIS idle speed motor bracket, bolts, and washers (I have found them on '81-'82 240s with CIS. They are mounted on the valve cover)

New:

aluminum reinforced epoxy putty (I used 'Quik Aluminum' bought at Home Depot)
head/manifold studs and nuts (2)
seal for shaft, P.N. 419568
seal (O-ring) for TPS
gasket for throttle body manifold, P.N. 1271488
gasket for block off plate, P.N. 463766
gasket for cold start injector (make your own)
vacuum hose, plugs, clamps, and caps
intake manifold gasket
Goodyear 17415 (41.5" long) belt for power steering. This belt may also be listed as 13AV1055 (13x1055mm).

Procedure

Prep the manifold:

Remove throttle body, spools, brackets, and vacuum nipples (optional) from manifold.
Clean manifold with degreaser.
Sandblast manifold (optional, but recommended for adhesion of epoxy putty).
Fill EFI holes with aluminum reinforced epoxy. (Some people have wanted to keep the option open of using the EFI injectors later, so they have either used carriage bolts to 'temporarily' plug the holes, tapped the holes with a M14X2 and plugged, or just kept the old injectors in the holes. I plan on running a 5th injector so opted to plug the holes)
Port the manifold if desired.

Here are the EFI injector holes before and after being filled.

A clean manifold and a tube of the epoxy putty.

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