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Best MPG in Si

siracergrl

Well-Known Member
1,063
577
NJ
Vehicle Model
Civic Type R
Body Style
4-Door Hatch
I need to find the picture hubby and I took on our way back from Grafixpressions. We had very similar #s too. Even recently when we went to visit his family we got 37 MPG and that's with my husband driving through Staten Island and Brooklyn
 

Adam

Well-Known Member
20
12
REQUIREMENT FOR PREMIUM GAS ON 2012 Si

I just wanted to make a note on this in case there are others out there like me who have the same quandary - this premium gas "requirement" was stopped me purchasing the - untill I poped the gas filler cover at the dealership........

Honda on every web site and spec sheet states that Premium is REQUIRED on the Si (confirmed at my dealership).

Yet, on the gas filler cover it states 91 octane is RECOMENDED. Its is well known (and stated on the Acura website), that 91 octane is RECOMENDED for the same Acura TSX motor.

In the industry there is a large destinction between REQUIRED (a must in order to prevent engine damage) and RECOMENDED (for full power and vehicle response).

I am quoting from the Honda Civic manual (the book that comes with the car):

" Fuel Recommendation
2.4 l engine models:
Unleaded premium gasoline, pump octane number 91 or higher.
Use of a lower octane can cause occasional metallic knocking noise in the engine and will result in decreased engine performance. Use of a gasoline with a pump octane less than 87 can lead to engine damage."

Just to keep this in perspective, - when going for a drive in the hills or going to enjoy the car I have no problem throwing in a few tanks of premium. However the unfortunate reality of my life is that most of the time, in my daily commute to work in heavy traffic or in snow covered roads I am lucky if I get out of first gear! In my area (Ontario, Canada) premium gas is more than $0.50 a gallon extra. Over a ten year period this can add to more than $3,000.00 on top of what I have to pay for regular and I don't want to sponsor the greedy (and wealthy) gas companies more that I have to: - so why pay the premium at times when I cannot enjoy its benefit?

So I am going to experiment with 87 during week days, but using Top Tier Detergent Gasoline only - need to minimise carbon hot spot deposits. I am expecting that the engine knock sensor will pick up knock and retard ignition and for sure I am expecting a noticeable loss of performance under 4,000 rpm under full load (gas pedal pressed deep) but I doubt I will ever miss the 5% power loss at the top end as with the Si real fast comes real easy!

And on week-ends, summer time and vacations - I will make sure she is topped up with premium - the best of both worlds! (or so I hope - I will let you know how it works out).
 

Adam

Well-Known Member
20
12
premium gas on most of the east coast is 93 octane. Read this - http://9thcivic.com/forum/threads/premium-gas-or-mid-grade.4017/

Thanks for the interesting discusion (again, some how I missed it).

Everyone always says that it's just a few cents and says that I should not have bought such a fancy car if I was worried over this- but gee guys, I like the car - a lot!

However over 10 years, say over 160,000 miles and assuming a good average consumption of 26mpg (I wish!) that is 6,154 gallons and, in my case, premium is really $0.50 more - so there is the additional $3,000. I guess I just hate giving the money to the greedy gas companies more than the average person. (Everywhere else in the world, like Europe, the price difference is around 2% not the 15% over here - no wonder most of the European brands are set for premium gas.)

Given that a lot of my driving will unfortunately be mostly in heavy traffic, where there is no point in charging up to the car in front and then braking - I cannot think that there will be any knock under light cruise conditions - so I do not understand why consumption under these coditions will be any different. (Sure I can think there will be a difference if someone is always hard on the pedal and always initiates knock conditions.) Also I think in very cold winter conditions there is very little chance of knock.

Anyway I will carefully monitor my gas consumption both on premium and on the cheeper stuff and report the averages (if anyone is intersted to know - I sure am intrigued to find out and I guess I will soon find out - my car is scheduled to arrive in 9 days time!).
 

webby

Administrator
Admin
Toys For Tots
52,336
22,453
you really can't gauge what is going to happen with gas over the next 10yrs. There are just way too many factors that dictate gas pricing.
If you look back at gas in 2002 (10yrs ago...)
The average weighted price at the pump nationwide, including all grades and taxes, was about $1.45 a gallon
other sources put it at 1.36/gallon ave in the US for 2002.

I wouldn't even want to bring up gas in Europe. In March of 2012
For the first time since June 2011, the average price for Gas across the 27 European nations just broke above $10/gallon USD.

it's not so much that engine load is dictating the car running premium... it's that the engine compression is high. 11:1

there are people who've also hit well into the 30's mpg wise in their SI. 26mpg is not a lofty goal that isn't achievable.
 

turbojay

Well-Known Member
45
27
Adam - I understand what you're saying but for me personally, the extra 25 cents is worth the peace of mind that I won't ruin the engine. I drive pretty easy but you never know when you need to gun the engine.
Also, My Si has been averaging 33+ MPG since I've owned it.


---
I am here: http://tapatalk.com/map.php?5h0xbz
 

Freddiii

Well-Known Member
1,252
605
Brooklyn, NY
Vehicle Model
Civic Si
Body Style
Sedan
Ive been running 89 in my Si. The guy who sold me the car told me it can take regular lol but I read the manual n it says 91. No 91 in NY so I run 89. Occasionally I run 93. Also accidentally put 87 once or twice. But I don't really notice a difference in between 89 n 93. In the summer I'll try n
It mostly 93 if gas prices continue to drop as they have.
 

bootyluvr

Supporting Member
VIP Member
Toys For Tots
20,175
7,796
Baltimore, MD
Vehicle Model
2015 Honda Accord EX-L V6
Why spend $25k on a car and then worry about few cents for premium gas. Just buy the lx or ex instead.

Exactly! People who care about MPGs should have bought a LX or EX!! Well said. I could care less what my MPG's are.. Didn't buy the car for that. Does one buy an Si for awesome MPGs? :confused:
 

Joey Icecream

Well-Known Member
3
2
Exactly! People who care about MPGs should have bought a LX or EX!! Well said. I could care less what my MPG's are.. Didn't buy the car for that. Does one buy an Si for awesome MPGs? :confused:

I bought mine because it was a great mix between the two :D (Originally turned away from the Si because of the premium constraint but that took literally one test drive of an 8th gen Si to change my mind)

First post ever btw and it's in a very informative thread!
 

Kiegell

Well-Known Member
19
6
Crofton, Maryland
Vehicle Model
Civic Si
Body Style
Sedan
I was a little intimidated at the thought of buying a car that required Premium Gasoline. However coming from a Pilot that I was getting about 18 mpg, I haven't really minded paying and additional 35-40 cents a gallon for almost double the mileage. I haven't done my own calculation, but according to the computer, I am averaging 33-34 mpg on each tank.
 

turbojay

Well-Known Member
45
27
I was a little intimidated at the thought of buying a car that required Premium Gasoline. However coming from a Pilot that I was getting about 18 mpg, I haven't really minded paying and additional 35-40 cents a gallon for almost double the mileage. I haven't done my own calculation, but according to the computer, I am averaging 33-34 mpg on each tank.

That's pretty good gas mileage. I've noticed the actual mileage is about 1.5 - 2 mpg less than what the computer shows.
 

Kiegell

Well-Known Member
19
6
Crofton, Maryland
Vehicle Model
Civic Si
Body Style
Sedan
That's pretty good gas mileage. I've noticed the actual mileage is about 1.5 - 2 mpg less than what the computer shows.

I haven't tried to calculate. I always did (at least in my head) on all my prior cars. I always wondered how the car calculated, and how accurate it was. Is it actually measuring the amount of gas is being consumed? Or is it trying to make an approximation?

The last week or so, the tempurature has been close to 100, and it has gone down about 1 mpg this tank of gas. I've noticed when I open it up on the highway 70+ mph, the computer reads higher mileage.
 

casualvic

Well-Known Member
22
12
I have also had great mileage when I drove moderately, and leave it neutral for slopes and such. I feel that my reflash, resonator delete with KN filter have helped. I am all about saving at the pump!!!!! I like how we can upgrade our vehicle for power, but at the same time save fuel when not stompin the gas pedal. I have been watching a thread in regards to civic HF under panels. I have a 2012 si and I only need to add 3 more panels in addition to what is already there. Concept is that the HF uses lighter rims lower, stance, and underbody panels for aero dynamics and better gas. I will do this soon in hopes to save on gas when im in grandpa mode
 

turbojay

Well-Known Member
45
27
I haven't tried to calculate. I always did (at least in my head) on all my prior cars. I always wondered how the car calculated, and how accurate it was. Is it actually measuring the amount of gas is being consumed? Or is it trying to make an approximation?

The last week or so, the tempurature has been close to 100, and it has gone down about 1 mpg this tank of gas. I've noticed when I open it up on the highway 70+ mph, the computer reads higher mileage.

I'm guessing it's approximating. I've gotten the best mileage when on cruise control between 55-65 MPH.
 
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