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Discussion Starter #1 (Edited)
I have a '99 Miata automatic trans. I bought it not running and it needs a head. Im having trouble finding a head and cams. Can I use a protege head? If so, what years? what mods if any are needed to make this work? Also what performance will be lost? I just want to get the car running for the wife, so just want reliability. Thanks, Rob
 

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I doubt a protege head will flow as well as a BP4W.

Wikipedia has your answers; http://en.wikipedia.org/wiki/Mazda_Protege Click on the motor options, see if they're the same used in the 99 miata.

You can put a BP4W head on a 94-97 BPZE block, so the head/blocks of the two motors are PHYSICALLY compatible. I would assume that using a non-99 head would throw the ECU into a fit, so you'd need an aftermarket ECU. At that point you could've just bought a BP4W head for less money. Look for them up for sale on craigslist (guamlist?)and from forum sponsors.
 

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Discussion Starter #3
how bout a BP05 head on a 99 block? just checking options since Im having trouble finding a BP4W head.
 

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Discussion Starter #5
I emailed an they dont have any, as well as a handful of other places. I didnt realize how hard it is to find that particular head. Just bought the car and now I may just sell if I cant get it the parts to get it running.
The guy on ebay said he has one but his feedback doesnt look too good, just dont want to get another bad head. Thanks though and the search continues....
 

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it will work but you will lose a lot of performance. talk to the guys at project G they can hook u up for around $450-500 for a used BP4W head. i bought one from them its nearly flawless
You wouldn't loose much performance. The 99 motor doesn't make much more power than a 97. Any 1.8 head mechanically fits on any 1.8 block. With a non-99 head, you'll need a NA ECU to control it properly. IDK if an NA ECU is plug and play with the 99 harness, sensors, etc. My guess would be, no, so you would probably need an aftermarket ECU, which means you'd need to tune it. Check the miata.net/miataturbo.net classifieds.

Again, using a non-BP4W head will probably be more trouble and money.

EDIT: What exactly is wrong with the head?
 

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you would need to modify the intake manifold in a big way.
Totally forgot about this aspect. A non-BP4W head would also mean a different exhaust manifold, EGR piping, maybe air box?


:BROKEN RECORD:

Wait for a 99 head.
 

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Mostly Harmless
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Short answer: yes, you can use a Protege head if absolutely necessary. There are some caveats to this, though, as already mentioned.

Any 1.8 head mechanically fits on any 1.8 block.
True. Make sure your headgasket is properly oriented before installing a replacement head. You might be surprised at just how easy it is to mess this up.

With a non-99 head, you'll need a NA ECU to control it properly.
False. Use the existing electronics, throttle body, et al., in the install and you'll be fine.

you would need to modify the intake manifold in a big way.
True. Port shapes are different, and stud placement is also different.
Had a buddy modify a '94 intake manifold for a '99 head, but there were still issues with the fuel rail not fitting nicely.

A non-BP4W head would also mean a different exhaust manifold, EGR piping, maybe air box?
False.
Exhaust manifolds are interchangeable between 1.8 Miatas. Stud placement is the same. Some manifolds just don't flow as well as others.
EGR pipe issues will depend entirely on whether or not the stock intake manifold is retained. If so, stock EGR pipe is fine.
Airbox? Really? Crossover tube...maybe, but doubtful. Stock airbox will be fine.
Might want to do a little more reading on parts interchange.
 

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False.
Exhaust manifolds are interchangeable between 1.8 Miatas. Stud placement is the same. Some manifolds just don't flow as well as others.
EGR pipe issues will depend entirely on whether or not the stock intake manifold is retained. If so, stock EGR pipe is fine.
Airbox? Really? Crossover tube...maybe, but doubtful. Stock airbox will be fine.
Might want to do a little more reading on parts interchange.

Educated guesses, didn't feel like dragging up my shop manuals. Airbox meant the crossover tube and sensors included, I was lazy and unclear. And the 99 IM is different from the NAs, BTW. Will the NA header meet up to an NB midpipe? The 99 has the female EGR fitting on the exhaust manifold. ERG will need to be bent and played with. Doesn't the NA using a different cam sensor than the NB?

Will A NA ECU be able to control a 99 alternator? Will it even physically plug into an NB harness? The socket plugs have different part numbers.

EDIT: And if all the manifolds can be swapped around, why does RB make the 01 header and the 94 header? Probably because they're different. I bet a s2000 exhaust manifold could slip onto the studs. I don't think that means it plug and play.
 

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Sell me your old Exhaust cam. CASH MONEY!
 

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By the time you bought all the parts needed to make this work, you could have paid for the bp4w head. The intake manifold, modify a fwd valve cover for rwd orientation, throttle body, VICS delete, egr differences, cross over tube, throttle cable, loss of power, etc would make the downgrade probably as expensive as finding another bp4w head with zero benefit.
 

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Discussion Starter #15
Guess I will keep searching. I wonder why that head is so hard to find? The demand seems to be there. No auto parts stores sell them? Nopi.com has it listed but when I called they said its not available.
 

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brontosaurus
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It's not a part that is produced and sold separately. If anyone has one it was taken off a wreck. I suppose one could buy a crate engine, but those are atleast $4,000.
 
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