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View Full Version : Mazda Miata NB BP4W (99-00) into 94-97 NA How To



iamdallas
07-11-2011, 02:02 AM
Thought I would try to put everything in one place. I know I've forgotten something, just let me know and I will fix it.

BP4W (99-00) into a BP (94-97) Car.

Things you will need.

The 99-00 Block, Head, Intake, VICS solenoid, RPM Switch to operate VICS, and Fuel Rail.

Alternatively, you can also just do a head swap and the procedure is exactly the same. Except, you won’t have to pull the block. In that case, all you will need is the Head, Intake Manifold, VICS stuff, and fuel rail

Things that will be used from your 94-97 Engine:

Throttle Body
Injectors

Anything Else Electrical:

All sensors from the 94-97 will replace the ones from the 99-00 engine. ALL OF THEM except for the VICS system, which your 94-97 doesn't have.

All sensors except for the one above the 94-97 oil pressure sender will be removed from your 99-00 block and replaced by the corresponding ones in the 94-97 block. This sensor will not be plugged into your wiring harness, but you will need it to stay in place to prevent an oil leak. If you want, you can plug the hole with a bolt to get it out of the way. I just left mine in place

On the rear coolant housing on the 99-00 head, there is an Allen Key stud in the lower driver’s side that will be have to be removed so that you can install the sensor from your old BP head.
Since you will have to use the 94-97 Fuel system, you should use the injectors from your 94-97 engine if they aren’t in bad shape (and you don’t plan any other modifications to the fuel system). The earlier model cars operated at a lower fuel pressure. If you use the 99-00 injectors, it will work fine but theoretically they aren’t operating at their optimal fuel pressure. I used the 99-00 injectors because my old ones were pretty much crap. :/ It all works fine for me.

Installing your CAS from the old engine is really easy! Something I didn’t know until I thought about it was that your timing will be off if the CAS isn’t at the right angle (rotated to the correct position). When you get ready to start the car and have worked out all other problems, have a friend turn the key while you twist the CAS until the car starts. From there you can adjust until the timing and idle are correct.

You can also use the BP4W Starter, as it is much lighter than the old one. I did, it goes on and is wired exactly the same as the 94-97 Starter.

If you have power steering and A/C and plan on keeping it, you will need to use the 94-97 components along with the alternator.

You don’t have to swap over all the coolant lines and everything like that from the old motor, they’re in the same place on the 99-00 engine, that saves you a little time and energy.

You may want to use your 94-97 Cam/Valve Cover as it doesn’t have the hole for the 99-00 CAS on the front. But, that’s not obligatory.

Fuel Rail:

You will need to take your FPR off the back of the 94-97 Rail, take off the damper off the front of the 99-00 Rail, and install the FPR in that position on the 99-00 Fuel Rail. You will then have a line pointing up, and one pointing down. The one pointing down is your supply line (the one that comes off the FPR pointing toward the front of the car, then turns 90 degrees and points straight down). You will need to install a length of 5/16 fuel hose (about 2 feet for good measure) to this BEFORE installing the Throttle body to make sure you get a good seal. It’s a super tight spot, even without the throttle body on. Your return line will then either run over your intake or around the back of the intake and into the top metal fuel line on the passenger side of the car. The supply line will run from the bottom one, to under the throttle body where I was talking about.

Variable Inertia Charging System (VICS)

You gotta have an RPM switch to control it. Since all RPM switches are different, I can't really tell you exactly what to do. However, I will add my specific part number and wiring diagram after I am sure that the switch I used will hold up.


If I forgot anything,or anything is wrong at all, remind me to add it and I will.