1.6 to 1.8 swap questions
 

hey guys doing a swap in a 90 miata. I have a complete 99 motor. i have basics down but i was reading i replace the fuel pressure regulator with the 1.6 for return system. do i need to replace the injectors to a earlier year do to them using base 60 psi? any help would be appreciated

Something about the NB injectors doesn't work well with a returnless system. I don't remember what it was.

Anyway, use your 1.6 FPR and NA injectors.

thanks is there any other 99 quirks i should look out for?

Something that I don't see anyone talk about much and that slowed me down for an entire day was the alternator bracket. I didn't have a 1.8 bracket so I had to cut/weld my 1.6 alternator bracket to fit. Find yourself a 1.8 bracket.

You're gonna have to bend the FPR nipple as well.

thanks good thing i have a few extra 1.8 motors on hand

You use the 1.8 injectors with the 1.8 rail and IM...running a 1.6 FP regulator.

I don't recall having any issues with the alternator...I may have just used part of the 1.8 bracket with my 1.6 alternator.

A little rich at redline, but they all seem to be like that: https://www.miataturbo.net/dynos-timesheets-21/n-2000-1-8-swap-minor-bolt-ons-57808/

I used a 94 alternator with a modded 1.6 bracket (should have used the lighter 99 bracket" and an M-Tuned rail.