Long Term 5w-30 use in Honda 1.5t

That's obvious, but what about fuel dilution above 4-5%, what do automotive/lubrication engineers have to say about it, normal? or its not in your domain of expertise?

How many times do you want me to repeat myself? Clearly, heavy fuel dilution isn't good. Use a thicker oil, and change it more often. UOA reports don't suggest the sky is falling. Don't be a chicken little.
 
Honda actually released a paper that talks a little about oil dilution and it compares multiple different engines they produce. Anyone can download and read it. Link

Here is a figure from the paper. Engine No. 6 (Purple) is the 1.5T and Engine No.7 (Light Blue) is the 2.0T. From their testing the 1.5T has worse oil dilution but the rate of fuel adhesion and oil dilution per cylinder appear to be similar between the engines. The 2.0T just holds a slightly larger quantity of oil for the size of the engine so the overall percentage is slightly less.
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This paper indicates that Honda is doing some R&D to find ways decreasing fuel dilution in the next gen engines, it would not surprise me that their next generation engine will have less of an issue with amount of fuel.
 
Honda actually released a paper that talks a little about oil dilution and it compares multiple different engines they produce. Anyone can download and read it. Link

Here is a figure from the paper. Engine No. 6 (Purple) is the 1.5T and Engine No.7 (Light Blue) is the 2.0T. From their testing the 1.5T has worse oil dilution but the rate of fuel adhesion and oil dilution per cylinder appear to be similar between the engines. The 2.0T just holds a slightly larger quantity of oil for the size of the engine so the overall percentage is slightly less.
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That's a tough read, but a good one. I agree with your interpretation that the 1.5 and 2.0 turbo Honda engines dilute roughly the same amount. Nobody bitches about the 2.0, but there is lots of complaints about the 1.5. Social media "trend" to bash the 1.5T. Personally, I like mine.
 
This paper indicates that Honda is doing some R&D to find ways decreasing fuel dilution in the next gen engines, it would not surprise me that their next generation engine will have less of an issue with amount of fuel.
I would already anticipate some of the changes mentioned to be on some production engines if they are talking about it on a publicly available paper, the OEMs tend to be very tight lipped until serial production. It wouldn't surprise me if some mentioned injection calibration changes were made for the MY22 1.5T Civics'.
That's a tough read, but a good one. I agree with your interpretation that the 1.5 and 2.0 turbo Honda engines dilute roughly the same amount. Nobody bitches about the 2.0, but there is lots of complaints about the 1.5. Social media "trend" to bash the 1.5T. Personally, I like mine.
It's not nearly as common of an engine, so there isn't nearly as many people to complain about it. But it has definitely been talked about on this site.
 
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love a good Christmas argument.

fwiw, i've yet to have my oil level rise to due to oil dilution. 37k miles of short trip city driving on my Si.
How do you know that oil is not burning off and being replaced by fuel? Did you measure fuel dilution through UOA?
 
How do you know that oil is not burning off and being replaced by fuel? Did you measure fuel dilution through UOA?
Unlikely but possible I guess. I check before every time I drive so I imagine I would see it rise. I have not done any UOAs yet. I have smelled gas on the dipstick but not enough to increase the oil level.
 
That S2000 engine was just a regular punter when you drove it around town, in fact having driven both generations of the S2000 I can say the AP1 felt so gutless around town I thought something was broken when I drove it the first time after the AP2. That, the B16/18, K20/24 were all extremely underwhelming until you got past 5000-6000rpm so I seriously doubt they taxed the oil as heavily as modern engines with DI and turbos that spool almost instantly, both on track and during normal commuting. Just because the F20 was one of the highest HP/L engines of its time doesn’t mean it was high stress, if it was high stress stock then its doubtful people would have built them up to 600hp+ without ever opening up the engines
I feel this is in my soul. I wonder if my k20 is a lawnmower when putting around town
 
So, common thinking by a fair number of people suggests that short tripping puts the vehicle into a "severe duty" drive cycle, which implies more frequent oil and ATF/CVT fluid changes. I've adopted this approach, anyway. When checking the Honda Civic Owners Manual and the factory service manual, I can't find any mention of this approach to maintenance. Only thing I see is a reference to driving in the mountains under heavy load, leading to more frequent transmission services.

Do other manufacturers specify more frequent oil changes when the car is primarily driven in the city all the time? Common sense suggests that short tripping results in engine oil that rarely sees full temperature, so moisture and fuel in the oil can accumulate. Honda doesn't mention anything, though.
 
On my 2.0t Honda engine, when I use 5w-30 it thins down to Xw-20 at 100C. So technically speaking I am just running the same viscosity as specified.
 
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