10th.gen hatch to 11th. Si fuel economy

[absolude]

Due to the AC disappointment of the 10th gen., I decided to switch cars so I'm now the very happy owner of a white 2023 Si.
The car is a huge improvement over my 2018 LX Hatch even though it had Si springs installed.
Only negative I can see is the worse fuel economy. This is surprising since I'm taking it easy at the moment.
FE is worse than previous car on either custom tune or stock, also compared to old car when 5W-30 oil was used.
The Si is about 160lb. heavier here in Canada. Would that make the difference?
Anyone moving from one generation civic to the next had similar experience?

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[aspitfyr]

My guess is fuel quality or driving habits.

 

[Shankmeyster]

I'm getting better average MPG's on my 23 Si than either of my 10th gen hatches. I don't know why you'd use 5w-30 if you aren't tracking the car. I've run multiple of these through Arizona summers on 0w-20 and no issues. That viscosity is gonna reduce your mpg's significantly.

 

[Shankmeyster]

Oh, they can also deny engine warranty if they find that you were using a different viscosity with an engine failure btw. It's real easy to send oil out for analysis.

 

[absolude]

Thanks for the responses.
I'm using the same 91 Octane Shell gas as before. Taking it easy since I'm still breaking it in.
I experimented a couple of times with the 5W-30 because I didn't like the rougher sound on 0w-20. Fuel economy was surprisingly close but I used an oil that had low viscosity for a 30 weight oil.

I heard in the past of cars having better FE after break-in. Maybe is time for me to experience that.

 

[absolude]

Oh, they can also deny engine warranty if they find that you were using a different viscosity with an engine failure btw. It's real easy to send oil out for analysis.

This oil recommendations are really strange. In Europe dealers would commonly use 5W-30 in these engines, especially for the manual ones.

 

[chopsuey34]

Thanks for the responses.
I'm using the same 91 Octane Shell gas as before. Taking it easy since I'm still breaking it in.
I experimented a couple of times with the 5W-30 because I didn't like the rougher sound on 0w-20. Fuel economy was surprisingly close but I used an oil that had low viscosity for a 30 weight oil.

I heard in the past of cars having better FE after break-in. Maybe is time for me to experience that.

You should use what Honda recommends, which is 0W20.

1.5T average fuel economy is known to rise even with 2000 miles on the odometer as the engine fully breaks in. If you are still in the break in phase, you should expect lower fuel economy. Report back at 4000 miles or so.

 

[VarmintCong]

Due to the AC disappointment of the 10th gen., I decided to switch cars so I'm now the very happy owner of a white 2023 Si.
The car is a huge improvement over my 2018 LX Hatch even though it had Si springs installed.
Only negative I can see is the worse fuel economy. This is surprising since I'm taking it easy at the moment.
FE is worse than previous car on either custom tune or stock, also compared to old car when 5W-30 oil was used.
The Si is about 160lb. heavier here in Canada. Would that make the difference?
Anyone moving from one generation civic to the next had similar experience?

My 2020 Si didn't get as good mileage as my 2017 Sport hatch, was your hatch manual? That might make a small difference as well.

 

[CivicR38]

I'm getting 35.9 mpg in my 2023 SI, very pleased

 

[absolude]

My 2020 Si didn't get as good mileage as my 2017 Sport hatch, was your hatch manual? That might make a small difference as well.

Yes, my hatch was manual. No power mods except the custom tune done by Derek.
I was getting better fuel economy on the tune than with the stock calibration.

 

[absolude]

I'm getting 35.9 mpg in my 2023 SI, very pleased

I think this is outstanding. Is it mostly hwy?

 

[absolude]

Just to clarify, the 5W-30 oil was used in the hatch only.
The Si only has about 400 miles on the clock.

A lot of people are using heavier engine oils with absolutely no ill effect.
5W-30 is among the oils recommended by Honda for the 1.5l turbo engine in Europe.
The 0W-20 recommendation in north America has more to do with the EPA fuel economy standards than longevity engine longevity.
With the fuel dilution the 0w-20 is getting dangerously thin in some cars, as found in oil analysys. Other than that is a great oil, since is 100% esters, IIRC.
https://www.civicx.com/forum/threads/oil-analysis-database.21607/

 

[CivicR38]

I think this is outstanding. Is it mostly hwy?

no, mostly 40 mile an hour cruising back and forth to work

 

[absolude]

no, mostly 40 mile an hour cruising back and forth to work

I could only dream .... Toronto turning so called Green City is a traffic nightmare.

 

[MorrisGray]

I would guess it is the gearing in the SI being for better 0-60mph time. More sporty and also tuned for more hp than the other Civic models and trims. You would need to compare 2023 SI mpg to a 2022/2021/2020/2019/2018 year model.

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