The other thing that will hurt you is the Chinese-ness of the turbo. The Chinese can copy the wheel sizes, but they don't do the geometry right, so their knockoffs consistently spool much worse than a genuine Garrett would.

The AR isnt a set size across all turbos. its a ratio and size depends on the turbos size.

something else to conisder is if your bottom end can handle the power a bigger turbo will produce? otherwise you are just increasing lag with your power limited by the stength of the bottom end.

Maybe I should measure the wheel size on the 2871 China turbo I have. They are claiming that even though it is stamped .86 AR that it's actually .64. Likely still too big for my 1.6 though.

Measuring the wheel size won't get you the information that you want. If it's t28, its t28. AR is relative to the area inside the exhaust housing.. tight or open, like hustlers poop chute.

https://www.miataturbo.net/attachmen...ine=1464290796

Understood. I was thinking I could at least compare wheel sizes to a know Garrett model.