Hey whats up,

I read a recent thread that you posted about your sohc and saw that you had swapped your CX head for an EX Vtec head.

I have just bought a 1997 CX Hatch and was wondering what kind of power gains did you achieve with the head swap. Before I read your post I didn't know it was possible to swap heads but was looking into it. Now that I know that it can be done I would like to know was the difficulty level of the install and what can I expect horsepower wise with the head swap and the usual AEM CAI, headers and exhaust.

Thanks for the info and good luck with the futur mods

 

I'm in the process of doing one too. I installed the ACT clutch today and Clutchmasters aluminum flywheel - both very nice. I have a 96 DX that I'm swapping a 96 EX head onto. The head is in the shop getting ported, and will be there until I get a chance to drop off the turbo manifold to be matched also. Check out my page for more details.

The level of difficulty should be pretty simple (especially compared to installing a clutch!!). If you'd ever used a torque wrench you can do the head swap. I'm using a BBK 62mm TB, which makes things a little more difficult because of the IAC, but if you want to just keep your CX TB, it will be pretty easy. I think the EX is rated at 30 HP more than the other Civics (besides the funky HX) so that's about what you can expect. Nothing huge, but something you can really feel, compared to the minimal gains you'll get from a CAI, header, etc.

 

what all is required for the swap?

 

From the EX donor:

Head (complete with cam, valvetrain, etc)
Intake manifold
Intake manifold support bracket
Throttle cable bracket
VTEC solenoid

Also:
New gaskets - TB, intake manifold, head

Options:
Re-used your TB, easiest thing to do. Have it bored by somebody like JG and fabricate a block-off plate for the IAC valve port, which is on the back of the intake manifold on the EX motors.

Your valve cover, fuel rail, and pressure regulator are the same as the EX - injectors are different, so you should get the EX ones. I think they are a tiny bit bigger.

You'll either need the EX ECU and harness (or you can spend hours modifying yours) which also means (I assume) you need a knock sensor. Or, you can use an RPM activated switch and a relay to avtivate VTEC. OR, get a Fields VTEC SFC (what I did) - also an overpriced Apexi V-AFC will work. All these things are just so you can activate the VTEC solenoid.

I think that's it ... you can go with an EX header also, which will mean you'll lose your cat. If you get both the header and exhaust made for an EX, you can either get a stock EX cat or an aftermarket. That's the way I would do it if I wasn't going turbo.

 

everything he said is right...for the longest time I thought VTEC wasn't working but, you just have to set the VTEC point anywhere above 5400 rpm... I used a Field VTEC controller to do that.

As far as gains, I really didn't notice anything drastic... SOHC VTEC is very weak compared to DOHC, but it is noticeable. You gain a lot of high end, so it does plull harder,

But as far as money goes, it is the best gains per dollar mod.

you on icq?
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