[Bob Paris]

The "newbie" suggestions recommend using mid-grade 89 octane fuel even though 87 is normal. What do you use and why?

 

[guitargain]

I have used 93 octane in my 2016 because I have a Trifecta Performance Tune. I am about to switch to 90ish non ethanol fuel since I have a buddy in the fuel business and now have a 275 tank with pump at home. I was told by Trifecta that it would do fine on the 90 octane.

 

[EricSmit]

I'd use the highest octane available. 93 where I am, 91 at altitude.

 

[Tonyb92681]

I found I get better economy and performance with premium. It might be anecdotal, but I believe it to be true.

 

[Chevy_Country]

I like a very few on here don't prefer premium. I recommend premium because most on here mention how they get better mpg, reduce turbo lag, and a smoother running car.

I noticed while on premium almost no rough idle, a from 2-3 mpg better, but no diference in turbo lag. So I switched back and run premium with seafoam every other oil change

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[Noiitekk]

I use 93 if available, otherwise 91 since not all stations nearby have 93. No real reason honestly but I like to think it nets me a slight increase in efficiency.

 

[jsusanka]

93 top tier pretty much about 95% of the time

 

[ProDigit]

I use 87 (which is the regular fuel over here; there's only a choice between 87, 89, and 91 where I live).

Never had any issues, save for when the temps are above 100F, then the car becomes really sluggish on the highways or interstates.
Still have to figure out if higher octane would help or not...
With 87 octane, the car operates best at temperatures around 60-70F (We don't get a lot of days with temps lower than that here), and performs good to 75F. A noticeable lower performance, but still good at temps of up to 95F, but beyond 95F, and especially 100+F, some serious lagging and weak performance.

When using BP premium (hi-octane) fuel, I get about 10% better MPG from most other fuels.
When using Shell premium fuel, I get about 5% better MPG.
When I use Chevron or Valero regular, I get about 5 to 10% worse MPG .

 

[shockz]

93 is a waste in these cars, unless you're tuned or in a very high altitude.

I'll put in the owners manual recommended 87 until it gets into Summer (over 80F), when I'll switch to 89/91 depending on the price. I won't bother with cruddy gas brands either... Shell, Sunoco or Marathon are the only ones I'll bother with.

My MPG remains a constant 35MPG (mixed) and my acceleration/lag returns to acceptable levels in the hotter temps with a bit higher octane.

 

[ChevyGuy]

Without checking my memory, I think the model year matters. 2011-2013 wasn't too happy with 87 when things got warm. I think 2014 on was fine. There was a recall for 2011-2013 with automatic transmissions that might have fixed this.

 

[Eddy Cruze]

Without checking my memory, I think the model year matters. 2011-2013 wasn't too happy with 87 when things got warm. I think 2014 on was fine. There was a recall for 2011-2013 with automatic transmissions that might have fixed this.

So true, the cooler months in the CRUZE only require 87 Octane in the 2014 Model. Summer months due to hesitation is well served with 89. 91 or 93 octane seemed to perform worse than the 89. I do not subscribe to the theory you must buy Top Tier as I see the same top tier station truck filling the non top tier station, and the price is even less at times. Means nothing to me, the Stooges sold "Burpoline" in the 40's and all Stations had/have their secret blend.

 

[NickD]

Why? Use to be able to tune my own vehicles for maximum fuel economy and performance, these two work hand in hand. Adjust the carburetor jets for a 14.7:1 AF ratio, and the spark advance to maximum without ore-ignition to gain the longest combustion cycle.

Yet another factor is compression ratio, the higher the better, one reason why diesels give better fuel economy, with direct fuel injection run about 20:1, 11:1 is about tops with gas. With low octane, get detonation, as the piston goes up, creates heat burning the mixture way before that spark plug does its job.

With a turbo, maximum CR can only be about 8.5:1, but with the Cruze, can jam in a lot more air into the combustion chamber that effectively does the same thing, peak pressures are as high as 35 PSI, much greater than atmospheric that at altitude can be as low at 10 PSI.

The O2 sensor keeps the AF ration at 14.7 and the anti-knock sensors produce the maximum spark advance, so with the new stuff, to gain extra performance simply by pouring in higher octane fuel.

Another way to increase octane is to add ethanol, start off with an 80 octane fuel and squeeze it up to 87, but not without problems, ethanol and gas to not chemically combine to form a homogeneous fuel. Ethanol is heavier than gas and first problem is getting a proper mix from the pump, second, when the car sits, ethanol will settle to the bottom of the tank where the fuel pump inlet sits and some of that ethanol is used first, leaving 80 octane fuel left.

Should be instructions to shake your vehicle first before starting it. Green people don't know anything about basic science.

Another objection to ethanol, its hygroscopic, holds moisture that causes corrosion and also attacks plastics. A true contradiction is you can only use E10, but not E15, both contain ethanol, only advantage of E10, takes a bit longer to cause fuel system problems. Ha, worked with Japanese, said Americans are stupid, no argument here from me.

Worse part of ethanol is using our food to power SUV's, can't buy a pound of hamburger for 50 cents anymore nor a pound of cheese, more like 5 bucks now! Forget about a New York strip steak.

You want reasons, learn something about the facts.

Gas is not very good either, HC's, H is okay, but its those C's that cause a lot of well over 100 year problems, very low heating value, a gallon is about 5.5 pounds of carbon, fouls your valves, blocks your fuel injectors, shorts out your spark plugs, and requires frequent oil changes and pollutes the air we breathe.

 

[ChevyGuy]

I do not subscribe to the theory you must buy Top Tier as I see the same top tier station truck filling the non top tier station

Top Tier assures you of minimum quality levels. Others might be ok, but the emphasis on "might".

Yes, you might see a Top Tier truck at that station - they might have won the bid that week. What will it be next week? Secondly, those tankers have multiple tanks - just to carry the different blends. Is it coming out of the same tank? And are you sure it's stocked with "Top Tier" gas for that particular trip?

And that "secret blend" might be what it takes to be a Top Tier. Leave it out and you may end up with deposits in your engine - even if you're starting with the same refined product.

Sorry, but one of my pet peeves is when someone says that a particular product comes from the same factory as another known brand. Sure, it comes from the same factory, but they may be "building to spec". Are you sure they're being built the same way? Maybe, maybe not. Short of careful and detailed analysis, you won't know.

 

[NickD]

Really no defined definition of Top Tier gas, does contain additives to help fight carbon build up, with some of these affecting our health, like MBTE's that can cause cancer in California rats, not sure about Wisconsin rats.

One reason why the cost of fuel is so high, EPA has 155 different blends causing maximum confusion in a limited amount of pipelines. Really don't have to prove if one blend is better than another.

Finally getting summer gas again, fuel economy is increasing by 25%, EPA is just concerned about that slightly longer warm up time during cold winter months as the current emissions systems are worthless until they heat up. But sure paying the price after the engine warms up.

 

[2015LT2]

I have been running the 89 in mine with good results. Gas is somewhat affordable now, although I would not consider my Cruze a performance car, even though she is a turbo.

 

[jblackburn]

I run 89 in my Gen 2, and will run 93 in summer months. Did the same with the 2012. 93 does help it avoid knock or hesitation more in hot weather.

Both seem to pull timing on 87 (so much so on the 2012 that it was almost undrivable at times), but do fine on 89. At sometimes 40c/gallon more for 93 than 89 in months where i notice no power gain or MPG gain, no thanks.

 

[obermd]

I've tested my 2012 ECO MT with 85 (regular in Denver), 87, 89, 91, and 93. Even in the winter I run 91 or higher. The EPA recall on the 2011-2013 automatics did retune them slightly to tolerate 87 octane better and the 2014-2016 Limited definitely run better on 87. The 2nd generation Cruze apparently runs fine on 87 octane as well.

I also tested a 2012 LS MT and found it performed slightly better and got slightly better fuel economy in Denver running on 91 octane as well.

Neither car I tested had an aftermarket tune.

 

[wasney]

I was running 93 for awhile. Now I am running E83!

 

[NickD]

We do have ten ethanol producers in the state of Wisconsin, state controlled, quite a variation between the ten of them. Also the gas station you purchase this stuff from, some do not have impellers to maintain this mix, so really don't know what you are buying.

Multiplied by 50 different states, can be either good or bad, so no set standards. Just use whatever you find to be the best. One thing about a gallon of gas, a lot cheaper than a gallon of milk. Farmers around here can make a lot more money selling their corn than feeding it to a cow.

 

[aaron.terveen]

91+no ethanol, I get way better fuel economy!

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