ND Miata oil questions

[Bill_W]

https://www.hexorcism.com/16ND/sh13083/

The ND Miata in North America has a two step oil pump controlled by engine variables. Different oil PSI bypass settings for different engine conditions. In North America the Operator's Manual says only use 0w-20 with SN rating

Same ND Miata in Europe and Taiwan gives two choices for oil weight. 0w-20 and 5w-30.

The above link shows a two step PSI bypass valve controlled by a on and off pilot valve. That pilot valve is controlled on and off by the car computer and adjusts by inputs from crankshaft sensor, water temp, mass flow, manifold air pressure.

The North American ND Miata has only one thermostat, the rest of the world has many different options.

I do not know if the programming is the same on my North American Mazda or it is the thermostat difference is what controls the pilot valve operation versus the rest of the world.

My water temp when warmed up is rock steady at 208 f (98 c) see temperature set on the oil control link.

1. Which oil choice 0w-20 or 5w-30 would you choose?

 

[Oildudeny]

I would run 0w20 all day long.

 

[VQ35DE]

0w-20

 

[JohnnyJohnson]

I would run 0W-20 in the Winter and 5W-30 in the summer.

 

[slug_bug]

DI engine. Oil always smells of gas when I change it. I go with 5w-30 figuring the fuel dilution thins it out. Change at 5k for the fuel reason as well.

 

[Bill_W]

Personally if my car works great with 0w-20 that means oil flow cooling is better than 5w-30. Gotta love Mazda engineering on the Skyactiv, to have 2 hydraulic oil steps on the oil pump bypass. With GF-6 coming less worry on IVD.

But the Operator's Manual for US says 0w-20 is required.

I just do not know if the PCM computer program is custom for US? A lot of Miata owners are influenced by internet backyard engineers that want to run outside the required oil weight.

 

[Gokhan]

Originally Posted by Bill_W
Personally if my car works great with 0w-20 that means oil flow cooling is better than 5w-30. Gotta love Mazda engineering on the Skyactiv, to have 2 hydraulic oil steps on the oil pump bypass. With GF-6 coming less worry on IVD.

But the Operator's Manual for US says 0w-20 is required.

I just do not know if the PCM computer program is custom for US? A lot of Miata owners are influenced by internet backyard engineers that want to run outside the required oil weight.

You're overthinking this. The SAE viscosity grade recommendation has nothing do with the oil pressure, oil pump, or coolant thermostat in modern engines. The viscosity varies a lot more with the oil temperature than with the SAE viscosity grade.

The minimum SAE viscosity grade recommendation is based on the minimum oil-film thickness (MOFT) in the bearings under the worst-case driving conditions (such as the highest oil temperatures and highest torque/rpm ratio). It's not based on the oil pressure.

You can use any SAE viscosity grade at or above the minimum recommended. Even SAE 60 would be OK. However, the recommended minimum of SAE 0W-20 will give you the smoothest-running engine, best throttle response, and best fuel economy. Don't fix something not broken unless you want to drive at high speeds, in which case a higher viscosity may be better suited. You may also need a higher viscosity if you have an oil-consumption issue.

 

[nascarnation]

These new 0W20s are beautiful oils and your Mazda has a beautiful engine. Ride with confidence.

 

[Bill_W]

Thanks... my oil cycle is next week and maybe next cycle some GF-6 (SP)

 

[Bill_W]

When you talk Gokhan, I listen. I put the thinnest oil in my engine because Mazda says I can. Here is a link to a Skyactiv 2.5 where they talk about the clearances.
https://www.import-car.com/pinpointing-oil-consumption-issues-now-you-see-it-now-you-dont/

 

[Gokhan]

Originally Posted by Bill_W
When you talk Gokhan, I listen. I put the thinnest oil in my engine because Mazda says I can. Here is a link to a Skyactiv 2.5 where they talk about the clearances.
https://www.import-car.com/pinpointing-oil-consumption-issues-now-you-see-it-now-you-dont/

Thank you for your kind words and thank you for the nice link!