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I have a 2017 Honda Civic Hatchback Sport Touring. I know it's recommended to use premium fuel because of the turbo and that's what I use but I was wondering what the negative effects of using regular fuel would have since it's only recommended and not required.
 

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Not an expert on this, but the type of fuel has to do with an engine's compression ratio and it's susceptible to pre-ignition when the wrong type of fuel is used.
 

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Discussion Starter · #3 ·
Not an expert on this, but the type of fuel has to do with an engine's compression ratio and it's susceptible to pre-ignition when the wrong type of fuel is used.
I read on another thread that cars with a compression ratio in the neighborhood of 8:1 can use regular fuel but I believe my car is 10.6:1. I'm not sure what "in the neighborhood" means exactly though. I'm assuming I should use premium to avoid any pre-ignition.
 

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Fuel is rated by its octane number, which is its ability to resist detonation. The octane rating, or octane number, is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating (igniting). In broad terms, fuels with a higher octane rating are used in high performance gasoline engines that require higher compression ratios. More specifically, in a normal spark-ignition engine, the air-fuel mixture is heated due to being compressed and is then triggered to burn rapidly by the spark plug. If it is heated (or compressed) too much, it will self-ignite before the ignition system sparks. This causes much higher pressures than engine components are designed for, and can cause a "knocking" or "pinging" sound. Knocking can cause major engine damage if severe.

The most typically used engine management systems found in automobiles today have a knock sensor that monitors if knock is being produced by the fuel being used. In modern computer-controlled engines, the ignition timing will be automatically altered by the engine management system to reduce the knock to an acceptable level. In these cases engine efficiency is reduced, power output is lessened, and carbon deposits may accumulate due to the fuel not being burned completely in an effort to prevent detonation.

With a compression ratio of 10.6:1 in these cars I'd agree with using a fuel with an octane rating of 91 (AKI, or (R+M)/2) or more. Octane ratings are calculated differently in various parts of the world and it is wise to understand the difference between RON and MON (Research Octane Number and Motor Octane Number). In the United States, octane rating is achieved by taking the average value of BOTH the RON and MON values.

What does this mean to us? Can we run "regular" (87 octane) unleaded in our cars? Yes, and more or less without damage, although you will find that you have better economy and better performance using a fuel with an octane rating of >89. I've personally found that the price difference between 87 and 91 octane to be about $0.30 per gallon, which means it's about $3.00 more per tank to use the "correct" fuel. If you do a little research you might find that some of the larger fuel stations offer a discount for using premium fuel if you join their rewards program (here in Minnesota the SuperAmerica brand offers a $0.10 discount to rewards members ONLY on premium fuel; SuperAmerica is also Speedway in other markets and may offer something similar).
 

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:nerd:Bang on with the above post, and to add, if you want to run regular vs premium that $3.00 savings will be mostly loss with less miles traveled per tank, not to mention loosing the fun factor.
 

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As an interesting side note to this: Honda recommends "regular" (87 Octane) unleaded fuel for the Civic, and has for years. Prior to my 2017 Hatch I had a 2007 EX Coupe with the 1.8L (R18A1) engine coupled to a 5-speed. 10.5:1 compression and 140 hp, but the specification from Honda was 87. Interestingly, my wife drives a 2013 Acura ILX which is directly based on the 9th Gen Civic; this car has the 2.0L (R20A1) engine coupled to the silky 5-speed automatic (one of the finest automatics I've ever driven, by the way). Also 10.5:1 compression and 150 hp, and the specification from Honda (well, technically from Acura) is "premium" unleaded of 91 Octane or greater. Basically the same motor in both cars, nearly identical architecture and output specification, yet one calls for regular fuel while the other calls for premium.

It's just my opinion, but your money isn't wasted by using the premium fuel. Even if you can't discern a performance difference (although I assure you that I could with the 2007 Civic, especially over 4,000 rpm), it's simply the right thing to do based on the engine specifications.
 

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On a separate note, and I'm aware that this is always a hotly debated issue on EVERY forum, but turbo engines desperately need clean oil in order to survive. Besides being clean it also needs integrity. . . Whether normally aspirated or boosted, I have long been a proponent of synthetic lubricants and feel that regular oil changes are key to long life.

I myself have owned approximately (65) vehicles, including a handful of motorcycles. Of this number, (17) of them have been Honda's purchased used or new, with both high and low mileage examples. In buying used I've noted that regularly maintained cars are pretty obvious in that they don't smoke or otherwise conspicuously use oil, whereas cars that got serviced annually (or even less often) had blackened rear bumpers and smoked mercilessly.

My point, though, is this: turbocharged engines are hard on lubricants, and if we hope for longevity then regular service and quality product are very important. I like Amsoil and I've been using their XL line (0W-20) in my 2017 EX and the wife's 2013 ILX, and I regularly change it at 5,000 mile intervals; the waste oil comes out a gentle smoky caramel colour and not black, which I view as encouraging. I also rotate my tires with each oil service to ensure best wear.

I offer this not to start an argument but to share my opinion and experience. I wouldn't advocate using a quality synthetic on a well-used and oil consuming 150,000 mile car, but for those of us with healthy engines and <50,000 miles on our cars it's a good idea worth considering.
 

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On a separate note, and I'm aware that this is always a hotly debated issue on EVERY forum, but turbo engines desperately need clean oil in order to survive. Besides being clean it also needs integrity. . . Whether normally aspirated or boosted, I have long been a proponent of synthetic lubricants and feel that regular oil changes are key to long life.

I myself have owned approximately (65) vehicles, including a handful of motorcycles. Of this number, (17) of them have been Honda's purchased used or new, with both high and low mileage examples. In buying used I've noted that regularly maintained cars are pretty obvious in that they don't smoke or otherwise conspicuously use oil, whereas cars that got serviced annually (or even less often) had blackened rear bumpers and smoked mercilessly.

My point, though, is this: turbocharged engines are hard on lubricants, and if we hope for longevity then regular service and quality product are very important. I like Amsoil and I've been using their XL line (0W-20) in my 2017 EX and the wife's 2013 ILX, and I regularly change it at 5,000 mile intervals; the waste oil comes out a gentle smoky caramel colour and not black, which I view as encouraging. I also rotate my tires with each oil service to ensure best wear.

I offer this not to start an argument but to share my opinion and experience. I wouldn't advocate using a quality synthetic on a well-used and oil consuming 150,000 mile car, but for those of us with healthy engines and <50,000 miles on our cars it's a good idea worth considering.
On top of changing your tires that frequent, are you also measuring the tread depth and how its wearing throughout the tire?
 

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On a separate note, and I'm aware that this is always a hotly debated issue on EVERY forum, but turbo engines desperately need clean oil in order to survive. Besides being clean it also needs integrity. . . Whether normally aspirated or boosted, I have long been a proponent of synthetic lubricants and feel that regular oil changes are key to long life.

I myself have owned approximately (65) vehicles, including a handful of motorcycles. Of this number, (17) of them have been Honda's purchased used or new, with both high and low mileage examples. In buying used I've noted that regularly maintained cars are pretty obvious in that they don't smoke or otherwise conspicuously use oil, whereas cars that got serviced annually (or even less often) had blackened rear bumpers and smoked mercilessly.

My point, though, is this: turbocharged engines are hard on lubricants, and if we hope for longevity then regular service and quality product are very important. I like Amsoil and I've been using their XL line (0W-20) in my 2017 EX and the wife's 2013 ILX, and I regularly change it at 5,000 mile intervals; the waste oil comes out a gentle smoky caramel colour and not black, which I view as encouraging. I also rotate my tires with each oil service to ensure best wear.

I offer this not to start an argument but to share my opinion and experience. I wouldn't advocate using a quality synthetic on a well-used and oil consuming 150,000 mile car, but for those of us with healthy engines and <50,000 miles on our cars it's a good idea worth considering.
With owning that many vehicles, which is phenomenal first of all, BUT in your opinion or if you have experience with it, what are your thoughts on Motul oil?
 

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@ 5TAR: Yes, most certainly. Regular inspection of tread depth when doing rotations will help indicate issues with alignment and tire inflation. With my 2007 Civic I found that tire wear was better and more even with the tires inflated to 36 psi (cold - like before being driven for the day, not a few minutes after driving) instead of the 32 psi that the tire placard called for. Also with that car regular tire inspection showed that there was an alignment issue with the RR tire that caused that tire to scrub and feather slightly even though the car drove and handled fabulously. A few trips to my favourite alignment shop and a replaced lower arm (no prior accident damage found, but replacing the lower arm brought the alignment into correction) solved the issue. People tend to neglect their tires, and as they cost so much today and don't seem to last I try to get the most out of them that I can, but I also tend to stick with better performing tires over cost conscious tire choices. I put 60,000 miles on the 2007 Civic over (22) months and I managed to get close to the retail value for the car when trading it in on my 2017 Hatch.

@ B20Vtec: I've used Motul in motorcycle applications only, but I've also used Red Line and Amsoil in bikes. My most recent ride was a 1992 Yamaha FJ1200, and it had 70,000 miles on it when I bought it. . . Much forum discussion indicated that for that particular bike Shell Rotella 5W-40 Synthetic was the best oil for high mileage air-cooled bikes. I rode that thing to 98,000 miles and my father-in-law still owns it and it has over 115,000 miles on it now, and it neither burns nor leaks any oil, nor has the engine been open, ever.

For cars I've experimented with Amsoil, Mobil 1, Castrol Syntec, and Royal Purple. I was always amazed at how filthy the Syntec looked when it was drained and I haven't touched it in (15) years. Mobil 1 is inexpensive as compared to many other brands and is available literally everywhere (Costco even carries it, although the price there isn't a huge savings over Wal-Mart), and I really feel like Royal Purple is more ideal for racing applications than a commuter car. I've been using Amsoil for the last (5) years based on reading (comparison tests) and my favourite metric: appearance after 5,000 miles. It tends to come out only marginally dirty to my naked eye, and when I pour out the waste into my transport jug there isn't ever ANYTHING nasty at the bottom of the pan like there was with Syntec. I'll admit that I change my oil almost too frequently; if you follow the indicator in the car it will have you change the oil (with assumed regular dino oil) between 6800-8500 miles, depending upon how you drive. I'm using a higher quality oil which should allow for longer life and a greater interval between changes, but I'm also not a wealthy man and I believe that better preventative maintenance is preferable to expensive repair or replacement.

But to your original question, sir: I've used Motul in air-cooled bikes and been satisfied with it. I live in Minnesota and the riding season is "short", and with the exception of my FJ I've never put really big miles on my bikes but I'd still change out the oil every spring as storage can be hard on the lube. Motul is fairly well rated and seems to be well liked from what I've read, but my experience with it is fairly limited so I can't really offer a solid opinion.

Sorry I didn't answer that with just the last sentence; I tend to go on about things.
 

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Not that I prefer to quote the wonks at Wiki, however, the information posted there regarding octane measurement and rating is a good entry primer for those who are unfamiliar:

https://en.wikipedia.org/wiki/Octane_rating

Living in the EU your fuel is likely measured using the RON (Research Octane Number) system. Those of us in North America (and many other parts of the world) have our fuel rated using the Anti-Knock Index (AKI) or (R+M)/2 method, which is the average of the Research Octane Number (RON) and the Motor Octane Number (MON).

Taken from another forum, here is a fairly simple chart for approximate comparison of octane ratings worldwide. This should not be taken as the end-all or be-all of this subject, but it may make the discussion easier for people in different parts of the world to comprehend.

www.pencilgeek.org/2009/05/octane-rating-conversions.html

@Rennokas: I'd imagine that if you're offered only two levels of fuel that the one with the higher octane number (98?) would be the more ideal purchase. It's a simple fact that high compression engines (compression ratios of >9.5:1) require fuels with greater resistance to knock.
 

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My point, though, is this: turbocharged engines are hard on lubricants, and if we hope for longevity then regular service and quality product are very important. I like Amsoil and I've been using their XL line (0W-20) in my 2017 EX and the wife's 2013 ILX, and I regularly change it at 5,000 mile intervals; the waste oil comes out a gentle smoky caramel colour and not black, which I view as encouraging. I also rotate my tires with each oil service to ensure best wear.

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I've used Amsoil since the 90's...don't worry about the color. Blowby combustion gasses will turn the oil dark, but has no affect on viscosity or lubrication. I change mine (and filter) once a year and have 230k miles on my '98 Civic.
 

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Yes thank you. I was curious about the same thing. Just bought an SI. The dealership filled it with 87 octane. I was doing some chill driving and got 23.5 mpg.

With 93 octane I am getting 26. I do get on it a little more now but 26 is far from the 28/38 honda says for econ.

all city driving.
 

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Yes thank you. I was curious about the same thing. Just bought an SI. The dealership filled it with 87 octane. I was doing some chill driving and got 23.5 mpg.

With 93 octane I am getting 26. I do get on it a little more now but 26 is far from the 28/38 honda says for econ.

all city driving.
Those sticker ratings are a lie - that's not just Honda. Unless you get AARP magazine, get discounts at Denny's, and occasionally forget there's a pedal to the right of the brake, you will never get anything close to those sticker ratings. I'm always happy if my highway mileage approaches what the "city" rating for MPG is.
If you have a commute that's got more than 3 minutes of surface road driving, even if 95% highway otherwise, you won't touch it.
And I suspect these Dr. Jeckyl / Mr. Hyde tiny turbo motors won't help that.
 
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