Anyone use regular gas in their Si?

Dharmaboy

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I only use Premium. Reason I bought this car over a WRX was because of the MPG. I get such incredible MPG with Premium on this car that the cost of the higher Octane doesn't hurt my wallet nor does it have me running to the gas station as often. Win Win.
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RogerRoger

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in NYC the pump octane is 87,89,93. I just did 120 miles on half a tank of 89 & half 93. Experienced best acceleration in a few months of using 93.
 

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2019 SI in NYC the pump octane is 87,89,93. I just did 120 miles on half a tank of 89 & half 93. Best acceleration in a few months of using 93.
I can almost guarantee it was due to the fact the weather is getting cooler compared to the previous months.
 

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in NYC the pump octane is 87,89,93. I just did 120 miles on half a tank of 89 & half 93. Experienced best acceleration in a few months of using 93.
That's it? My last trip in August I did almost 400 miles on a full tank (91 octane) driving from Northern Cal to Southern Cal, 80 mph in about 104 degree F heat. When I reached LA I had about a little less than a quarter tank, could have done maybe another 50 miles
 

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I use 87.

Did not lose ANY gas mileage, still averages 32mpg with me cruising at 85-90mph and driving it aggressively around town.

It still has no issues doing 120+mph, its abilities are not hindered at all.
Went on a 12 hour road trip and averaged 40mpg passing cars and doing 85mph.

I don’t race so I really don’t care about 15hp lost.. I still enjoy the suspension, chassis, seats, sound system, crisp shifter, steering..
 


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The difference in gas cost is a very inexpensive way to get the best out of your SI.

I am cost conscious, and even I won't put regular gas in a high output turbocharged four cylinder engine.
 

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It’s funny how so many people commenting here believe their smarter than the Honda Engineers that built this engine. Do you really think they didn’t consider the facts for what would happen to this engine if only regular unleaded gas was used? Reading your comments always make me laugh.

Will premium gas make the engine perform better? Yes.
Will premium gas give better gas mileage? Yes.
But nothing noticeable because it’s so small.

Will regular unleaded hurt this engine? NO
Bravo! It took 7 pages of reading to read exactly what I was thinking. I have alternated between 87 and 93 and noticed no difference, my mileage is 38.8 average regardless. My si is my daily driver. It checked many boxes for me when I was shopping for a sedan, it does what I want and expect, if I desire to go Mach 2 with my hair on fire two bays down sits a Shelby GT500 convertible.
 

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I use 87.

Did not lose ANY gas mileage, still averages 32mpg with me cruising at 85-90mph and driving it aggressively around town.

It still has no issues doing 120+mph, its abilities are not hindered at all.
Went on a 12 hour road trip and averaged 40mpg passing cars and doing 85mph.

I don’t race so I really don’t care about 15hp lost.. I still enjoy the suspension, chassis, seats, sound system, crisp shifter, steering..
Would you kindly share your VIN?
 

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thebutcher said: ↑
It’s funny how so many people commenting here believe their smarter than the Honda Engineers that built this engine. Do you really think they didn’t consider the facts for what would happen to this engine if only regular unleaded gas was used? Reading your comments always make me laugh.
Will premium gas make the engine perform better? Yes.
Will premium gas give better gas mileage? Yes.
But nothing noticeable because it’s so small.
Will regular unleaded hurt this engine? NO
Bravo! It took 7 pages of reading to read exactly what I was thinking. I have alternated between 87 and 93 and noticed no difference, my mileage is 38.8 average regardless. My si is my daily driver. It checked many boxes for me when I was shopping for a sedan, it does what I want and expect, if I desire to go Mach 2 with my hair on fire two bays down sits a Shelby GT500 convertible.
This is exactly what I've experienced between 87 and 93. I drove across country from Florida to Las Vegas, when I tried Premium there was no noticeable difference and trust me I was driving 12-14 hours a day if there was a difference in MPG or power/performance I would have noticed it.
This being said, I guess the next question is if I was to buy any other car than my Si(which I'm perfectly happy with) what would I go with? I'm pretty choosy and I don't like most of the newer cars out there, almost all are disappointing. The only cars I'm interested in are 1. Kia Stinger; but it's a Kia. still very nice car 2. Tesla Model S; could buy used for 45K but no, hell no. 3. Civic Sports Hatch; hard to move down from Si but I could use the extra room.
 


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thebutcher said: ↑
It’s funny how so many people commenting here believe their smarter than the Honda Engineers that built this engine. Do you really think they didn’t consider the facts for what would happen to this engine if only regular unleaded gas was used? Reading your comments always make me laugh.
Will premium gas make the engine perform better? Yes.
Will premium gas give better gas mileage? Yes.
But nothing noticeable because it’s so small.
Will regular unleaded hurt this engine? NO

This is exactly what I've experienced between 87 and 93. I drove across country from Florida to Las Vegas, when I tried Premium there was no noticeable difference and trust me I was driving 12-14 hours a day if there was a difference in MPG or power/performance I would have noticed it.
This being said, I guess the next question is if I was to buy any other car than my Si(which I'm perfectly happy with) what would I go with? I'm pretty choosy and I don't like most of the newer cars out there, almost all are disappointing. The only cars I'm interested in are 1. Kia Stinger; but it's a Kia. still very nice car 2. Tesla Model S; could buy used for 45K but no, hell no. 3. Civic Sports Hatch; hard to move down from Si but I could use the extra room.
it's always better to buy used, especially if you are buying 1) an expensive car and 2) a car known for it long term reliability. Let someone else break it in and depreciate it for you
 

amirza786

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Would it be bad to go back and forth between 87 and 91?
The answer depends. Do you believe in the scientific method? Than the answer is no. Do you believe in opinion or what your gut tells you? Than the answer is yes

Personally I would use 91 because you do get better performance, and it is recommended
 

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I am not sure of this but seems like these engines in Si's don't get as much crud in the intakes unlike other GDI engines. So a reason could be design and spec on the octane being higher. Can anyone confirm this?
 

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I am not sure of this but seems like these engines in Si's don't get as much crud in the intakes unlike other GDI engines. So a reason could be design and spec on the octane being higher. Can anyone confirm this?
Likely has nothing (or very little) to do with octane. Seems like Honda is doing some stuff with the valve angles and overlap to allow some fuel to spray the backside of the valves.
 

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On Costco the difference of regular to premium around 60 cents a gallon,Since car is use daily,half tank regular and do half premium little over on both. Did not see any difference on power or MPG.Yes it said premium recommended.
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