MX-3.com

Before you all start criticizing me, I've searched. I've looked, I've asked, I've laughed, I've cried, and got sidetracked many times in between.

I'm on a super-tight time schedule, I need some things done, and I need them done ASAP. Specifically this swap. I've HAVE to do an engine swap, I'd very much rather up it to the 1.8 than go back to a B6.. BUT! Situation and time prevents me from doing the work myself, and to possibly be out of a vehicle for a very long time.

I'm asking someone, ANYONE who's performed a swap from the DOHC to DOHC to please guide me to any discrepancies I will encounter. There is EXTENSIVE information on SOHC with very basic insult-your-mother directions, but I have to know what is different, what i have to consider doing said swap on a '95. I need to know so I have all the possible information available to hand to a mechanic so I can get my car done and running. I will bestow karma on whomever wields this information. Lots of karma. In fact, I"ll rob myself of my own Karma, and give it to you. Cookies might be involved as well. Depends.

Only one person I've found has done said swap, but two discrepancies that disturbes me:

he used an ATX tranny; I've a MTX.

He used the 2nd gen protege BP; whether the process is the same with 1st gen, I know not.

For 90-94 BP swap into B6DE you will need
-BP engine
-BP MAF
-BP wiring harness
-BP ECU

If you go with the protege tranny you will probably need
-BP axles
-BP hubs
-MX-6 Speedo

If you keep your tranny you may not need that stuff but you have to drive very carefully i guess.

Also the dash wiring might be different - so you might have to cut and splice mx-3 connectors into the BP harness (i had to do this for the newer BP).

I am not sure about the exhaust pipes - it may not lineup - if you are unlucky - you might have to do a custom down pipe.

The list is not comprehensive.....

MX-3 has a Mazda F-series gearbox. This transmission should hold up well to any of these engines (speaking of BP's). It has taller gear ratios which are geared for fuel economy over performance and smaller, 22mm diameter axles. It has been known to hold up to about 200 horsepower and ft-lbs of torque without reliabilty issues when not abused.

I do a lot of highway driving. The gear ratio's spread would suit me best, and a base BP looks like it's not too capable of killing the tranny. If I go BPT in the future, I'll definitelylook into new tranny. Thanks so much!

ariesdude wrote:For 90-94 BP swap into B6DE you will need
-BP engine
-BP MAF
-BP wiring harness
-BP ECU

If you go with the protege tranny you will probably need
-BP axles
-BP hubs
-MX-6 Speedo

If you keep your tranny you may not need that stuff but you have to drive very carefully i guess.

Also the dash wiring might be different - so you might have to cut and splice mx-3 connectors into the BP harness (i had to do this for the newer BP).

I am not sure about the exhaust pipes - it may not lineup - if you are unlucky - you might have to do a custom down pipe.

The list is not comprehensive.....

I hate to be the one to bithc, but you have a few things wrong in here.


First off, I have done a 94 swap to an OBDI BP from a 93 proetge lx.

As told above, you will need the eninge, wiring harness, ecu, and maf. Be sure your engine is complete with intake and exsaust manifolds as of these do not match on the motors. Also be sure the exausts side goes all the way down to the flex pipe, this is important. On the intake side be sure you get the plastic tubing unless you already have the elbows you need to swap over for a diffrent style intake. Clearance can be an issue pending how your intake sits.

I fully advise going with the protege lx tansmission, they are stronger and lower geared. If you dont have the money though you can use your old one. If you do though, you need the Transmission, flywheel, clutch but you do not need to swap the hubs. The MX-3 ones work. If you want a speedometer you need to pull a gauge cluster from a 92-93 and convert over to a cable speedometer.

Remember how i said be sure the exsaust side you got all the way to the flex pipe? That saves you some custom exsaust work, but you still need to have fabricated a flanged exsaust to bolt up to it. This will save you money by getting the complete part.

The dash harness plugged into the 93 ecu we had. Everything worked as well, with the exception of the speedometer which as i said above you need to convert to a cable driven one.

I can never remember on the motor mounts but I do recall you need to modify one of them, and by that i mean grind one part down and make it so the bolt goes through it in reverse. This keeps it from colliding with the shifter linkage.

I fully advise to keep a slush fund on hand when doing something like this, there are always those little things that peopl forget but if you look in the faqs and poke around enough you really can find it all. In the world of engine swaps though this has to be one of the simplest you can do.

ariesdude wrote:For 90-94 BP swap into B6DE you will need
-BP engine
-BP MAF
-BP wiring harness
-BP ECU

If you go with the protege tranny you will probably need
-BP axles
-BP hubs
-MX-6 Speedo

You don't need BP hubs for a protege tranny swap, although if you have over 150,000 miles i would change the wheel bearings which are a pain. Also I would swap out the gauge cluster for a speedo cable. You have a hole right in your firewall for a cable.

This is going to be a bit more pricey than I thought...
Unfortunately, I have no place for a donor car, as I live in apartments... If they see a junker out in the lot, someone's going to complain, and it's going have to go.
All the parts I need will most likely have to be shipped to the shop directly when the swap begins. Money is also an issue, so I'll be keeping my tranny. This'll save me purchasing one, and also having to pay for labor on axles, speedo modification and whatnot.

also E/I manifolds, I'm not sure if these imported/refub motors come complete with the manifolds, I"ll have to call and see what it all includes. Most likely it'll be ending up in custom exhaust work.
I heard some debate on the 2nd gen 1.8L's, something about OBDI vs OBDII... I'd like to opt for the 2nd gen swap. Are there any further discrepancies I have to account for? Possibly differing harnesses?

I'm finding this very helpful. Thanks for all of your input. You guys are great