Who's right? (or closer to right): Oil specification for my old Fiat Abarth, 5w40 or my new Honda SI, 0w20?

[OVERKILL]

Would it be logical to assume, then, that the xW-20 oils specified by manufacturers would tend to be at or above the 2.6?

2.6 is the bottom limit for xW-20 in J300.

 

[kschachn]

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[kschachn]

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Well you beat me to it and your post was more clear

 

[Slow Car Sport Mode]

2.6 is the bottom limit for xW-20 in J300.
View attachment 87268

Ahhhh.. got it.

 

[TeamZero]

My 2012 Fiat Abarth manual specified 5w40, my 2022 Honda Civic SI manual specifies 0w20. The engines are almost the same displacement, 1.4 vs 1.5, and they're both turbocharged. The Fiat Abarth was port injected while the Honda SI is direct injected, so there's that.

Why the (seemingly) very different oil specifications? Is it the decade between the two cars that's the difference? Did the auto industry and engine needs "evolve" a lot in that time? Are these two engines are more different than I'm guessing they are?

The Fiat engine seemed to really like the 5w40, going strong at 70,000 miles when I got rid of it.

Thanks.

I didn't bother to read all 6 pages, as this post as gone off the rails I assume. Aaaaanyway, the Fiat 1.4 is an old design engine from a ways back(other the the multiair) , and is somewhat tough on oil. Even the non turbo 1.4 specs 5/30

 

[Hoover]

I didn't bother to read all 6 pages, as this post as gone off the rails I assume. Aaaaanyway, the Fiat 1.4 is an old design engine from a ways back(other the the multiair) , and is somewhat tough on oil. Even the non turbo 1.4 specs 5/30

Yeah, the discussion did kinda range around, but it's helped me with my decision regarding oil for my SI. From the discussion in this thread and in other related threads I've browsed through, it seems that 0w20 is fine, but a spec that's close to 0w20 appears to be fine also. Right now I'm leaning towards using and oil spec that's just a bit less all-about-mileage . Just have to learn/decide what specification that should be (what's the nearest thing to 0w20? Is it 5w20 or 0w30?)

 

[kschachn]

Yeah, the discussion did kinda range around, but it's helped me with my decision regarding oil for my SI. From the discussion in this thread and in other related threads I've browsed through, it seems that 0w20 is fine, but a spec that's close to 0w20 appears to be fine also. Right now I'm leaning towards using and oil spec that's just a bit less all-about-mileage . Just have to learn/decide what specification that should be (what's the nearest thing to 0w20? Is it 5w20 or 0w30?)

The grade that's next higher than a 20-grade is a 30-grade. Winter rating is not involved.

 

[Shel_B]

The Honda may have wider bearings to account for the reduced viscosity. So yes, the engine design may be a fair bit different.

So, if an engine is designed for a thinner oil, as opposed to just being spec'ed for it, would running a thicker oil be detrimental in any way?