Does anyone know if there are physical differences in first gen 2.0L Skyactiv engines? When I look up engine specs the 2016 MX5 and CX5 are both rated at 155hp, and 13:1 cr. However, MX5 redlines at 7500rpms, while the CX5 at 6800rpms (manual). For fuel the MX5 gets a "premium recommended" while CX5 is "regular unleaded". I was curious if the differences were strictly tune based, if there were significant intake/exhaust changes, or if there are internal differences between models.

 

The ND1 (2016-2018) engines didn't redline at 7,500. They only went to 6,800 for that 155 hp. The ND2 (starting 2019) can go to 7,500 and is rated at 181 hp. I am sure the ND1 intake manifold is different from the CX5 version. The ND1 engine also gets an aluminum valve cover instead of a plastic one on the CX5.

 

They are different engines. Different part numbers for intake and exhaust cams, different part numbers for the crankshafts, and even the cylinder head castings are different part numbers. If you’re in need of a replacement 2.0 ND1 motor you’ll just have to pony up for a replacement from another Miata

 

You can fit an ND2 cylinder head on ND1 blocks for extra performance, afaik.
Cost effective ? Obviously not.