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I've been reading comments concerning the extra expense of running higher octane gasoline in the 2.0 turbo. We've put 8,800 miles on a 2019 Redline all on 87 octane gas with no knocking, pinging or performance problems. The owner's manual allows the use of 87 octane unless knocking occurs. 93 octane is recommended - not for engine longevity but for performance and better economy. At best 93 octane gas is about .30 (or 15%) more than regular gas. Has anyone tried comparing fuel economy of premium vs. regular? If gas mileage is 15% or more higher with 93 octane it would make sense to use it.

The owner's manual does recommend 93 octane for towing.
 

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I bought my 2.0 in July. Service manager told me regular would be fine. I have used mostly 87 octane with no problems. I have tried 89 & 93 octane. Best gas mileage has been with 89. I have over 8000 miles on the vehicle. Usually get around 24 mpg. With 89 around 25-26, Two tank fulls of 93 was the same as 87. Does seem to feel a little quicker with the 93 though.
 

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I had tried both 87 and 91 (93 is hard to find near me) for several months/fuel fills each. I didn't observe any significant MPG difference, either via the DIC or hand calculated. Perceived performance was nearly the same, with a slight nod towards 91 octane.

The biggest difference was the amount of soot a the chrome tip on the tailpipes. There's much less with 91 octane, but still some soot.

While I didn't have any issues with the 87 octane fuel, I decided to go with 91 not knowing what the long term effects would be with 87. I tend to keep vehicles a long time. The trade-in for my '18 Terrain was a '98 Pontiac minivan, which itself was purchased new after I totalled an '81 Chevy. I still have my very first vehicle, a '67 Chevy Camaro.
 

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I have a 2019 Redline 2.0 that has only been fed 93, sometimes 91 octane fuel. I've never experimented with using 87 or 89.

These small displacement, direct injected, turbo boosted engines have the tendency to exhibit the LSPI phenomenon that has preceded internal engine damage/broken pistons.

This along with the 9 speed transmission that tends to favor shifting into a higher gear ratio sooner than maybe desirable; this tends to make the engine lug somewhat, contributing to a pre-ignition issue.

Another factor is summer driving in hot ambient temperatures with the AC on, thinner air, leaner air/fuel ratios and higher expressway speeds; this also places extra demands on these tiny engines that could enhance a pre-ignition issue.

I do realize that the engine is calibrated for 87 octane, and under many conditions this is an adequate fuel choice. If the engine controls sense a knock or excessive temperatures, the computer will do a couple of things; one is to pull timing advance, the other is to add fuel; both of which aren't desirable for performance or economy. The problems arise when the engine control systems cannot compensate enough to protect the engine, and the operator doesn't realize there is something going wrong.

Because of the above concerns, and the GM powertrain engineers high recommendation of using premium fuels; personally I will use the recommended octane, as I'm not one to gamble losing an engine to save a few dollars worth of fuel.

Note: This is my perception and an opinion; I'm not saying using one fuel or another is either right or wrong; it's just something to consider before making a decision how to fuel your vehicle.

.
 

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In some cases wording gets flipped during the discussion on Top Tier Fuels to Premium Fuels and Premium Fuel. While the GM recommendation on the 2.0 turbo is to use 93 or above according to the manual, it also states that 87 can be used as long as you don't experience knocking, etc..

Regardless of what octane you are using, if it is not a Top Tier Fuel, you increase your risk of pinging, knocking and soot buildup. The specific blends that meet the recommendations of some manufacturers, and GM is one of the manufacturers, the information about Top Tier fuels can be found here. https://www.autolist.com/guides/top-tier-gas

If anyone is using a lower octane and other than Top Tier fuels, then the chances of increased soot or other issues increases. If a vehicle is used as a standard passenger vehicle, no harsh driving, weather or towing, then a lower octane, within the vehicle manufacturers requirements, with a Top Tier fuel should be fine. For my own vehicles, I use Top Tier fuel and 87 octane the majority of the time. If I get into a state that their regular is less than 87, then I go up to mid-grade, the state minimum requirements are available here: https://en.wikipedia.org/wiki/U.S._State_Fuel_Octane_Standards

When I'm going to the mountains, then I make sure that I am using a minimum of 89 since I know it will be working more pulling the inclines. As for the mileage, I have noticed any real difference with the octane level, but I do see a difference between winter blend and summer blend, with better mileage coming from summer blend.
 

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Turbos = premium Non turbo = regular except my Malibu that has a tune in it. That's how I feed my fleet.
Little baby turbo motor hardly uses gas and that is on the boost more than you realize and being ''frugal'' for a buck or two a tank of gas isn't worth it. IMO better bank that savings as you will need it down the road.
 

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Agree with the above and do generally the same in our 3 GM vehicles. Mostly run 87 ethanol blend in two of our vehicles.

Interestingly, I do most often run 91 or 93 octane in our 2017 1.8L Sonic. One reason is -

with the OBD II scanner hooked up I could see timing getting retarded under even some moderate spirited gas pedal pressure. I'm talking about enough to get into mid torque curve at 3,500 to 4,000 RPM shift points, but even at 2,500 RPM timing was getting pulled by the ECM to prevent knock.

Now, mostly we don't drive in the "spirited" manner and strive to hold the RPMs in the 4,000 RPM for shift points, so we many times just go with 87 or 89 at fill up time.
But with only a 12 gallon tank and getting 29 to 33 MPG, putting 91 or 93 in the tank isn't that much of a cost factor.


But the point is, for some cars, or even many, it would a good idea to hook up a scanner and and see if knock retard is occurring in order to see whether your particular driving style might benefit from using a higher octane.
 
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In our's as I have shared before we use 89 for all driving other than when we go on a trip, then we burn premium.

The concern I plan to try and verify this issue this upcoming summer with a spark plug read, is the extreme low rpm loads that are placed on these motors as many here have stated due to the automatic transmission shift points. Look at it this way, with my Harley or if this 4 banger had a manual trans I would never run the RPM's under 1700/1800. I routinely see this motor run at 1200 RPM's and IMO that is just to low for a motor this size with this compression.

Many concerns raised here about heavy loads small motors and high compression increasing the need for Octane. This low RPM issue I am hoping to address with a program tune that allows me to set the min RPM's at my minimum.

1200 RPM's and the savings that buys us at the pump is the equivalent of the pennies we save by shutting off the motor every time the vehicle stops...another penny wise dollar foolish decision we have been forced to accept or not.

I have worked in oil industry for nearly 40 years and make decisions daily based on risk and experience...neither of these options pass my risk adverse test and as I said if I can change the ECM shift points I will be doing that down the road...
 

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Agree with the above and do generally the same in our 3 GM vehicles. Mostly run 87 ethanol blend in two of our vehicles.

Interestingly, I do most often run 91 or 93 octane in our 2017 1.8L Sonic. One reason is -

with the OBD II scanner hooked up I could see timing getting retarded under even some moderate spirited gas pedal pressure. I'm talking about enough to get into mid torque curve at 3,500 to 4,000 RPM shift points, but even at 2,500 RPM timing was getting pulled by the ECM to prevent knock.

Now, mostly we don't drive in the "spirited" manner and strive to hold the RPMs in the 4,000 RPM for shift points, so we many times just go with 87 or 89 at fill up time.
But with only a 12 gallon tank and getting 29 to 33 MPG, putting 91 or 93 in the tank isn't that much of a cost factor.


But the point is, for some cars, or even many, it would a good idea to hook up a scanner and and see if knock retard is occurring in order to see whether your particular driving style might benefit from using a higher octane.
JayTee--Thanks for sharing your experience with the scan tool showing timing being pulled. I have used premium in my 2.0 under the assumption that would happen--timing being pulled--even when I couldn't hear the engine actually "pinging" under load. Your experience validates--for me at least--the decision I have made and operate under. Thanks again for sharing!
 

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The concern I plan to try and verify this issue this upcoming summer is the extreme low rpm loads that are placed on these motors as many here have stated due to the automatic transmission shift points. Look at it this way, with my Harley or if this 4 banger had a manual trans I would never run the RPM's under 1700/1800. I routinely see this motor run at 1200 RPM's and IMO that is just to low for a motor this size with this compression.

Many concerns raised here about heavy loads small motors and high compression increasing the need for Octane. This low RPM issue I am hoping to address with a program tune that allows me to set the min RPM's at my minimum.

1200 RPM's and the savings that buys us at the pump is the equivalent of the pennies we save by shutting off the motor every time the vehicle stops...another penny wise dollar foolish decision we have been forced to accept or not.

I have worked in oil industry for nearly 40 years and make decisions daily based on risk and experience...neither of these options pass my risk adverse test and as I said if I can change the ECM shift points I will be doing that down the road...
I concur completely.
 

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Agree with the above and do generally the same in our 3 GM vehicles. Mostly run 87 ethanol blend in two of our vehicles.

Interestingly, I do most often run 91 or 93 octane in our 2017 1.8L Sonic. One reason is -

with the OBD II scanner hooked up I could see timing getting retarded under even some moderate spirited gas pedal pressure. I'm talking about enough to get into mid torque curve at 3,500 to 4,000 RPM shift points, but even at 2,500 RPM timing was getting pulled by the ECM to prevent knock.

Now, mostly we don't drive in the "spirited" manner and strive to hold the RPMs in the 4,000 RPM for shift points, so we many times just go with 87 or 89 at fill up time.
But with only a 12 gallon tank and getting 29 to 33 MPG, putting 91 or 93 in the tank isn't that much of a cost factor.


But the point is, for some cars, or even many, it would a good idea to hook up a scanner and and see if knock retard is occurring in order to see whether your particular driving style might benefit from using a higher octane.
What scan tool are you using and which PID are you monitoring. My UltraGauge and Bosch only shows current timing advance.
 

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All the gasoline in my area comes out of the same terminal.The tankers are operated by different companies with no brand name on them. The terminal used to be Standard Oil. Not sure what it is called now. Not sure which brand of gas I am buying at any local station.
 

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LSPI is not guaranteed not to happen if your using High Octane. Its was discovered that the oil is one of the reason for it. This is why GM changed its Oil specs and Amsoil is the only Oil that beats the GM LSPI occurrence specifications. All other Oil that are Dexos meet the specification for LSPI prevention. They made some chemical changes to the oil to stop LSPI.
 

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They made some chemical changes to the oil to stop LSPI.
I don’t understand this statement. The oil is not even in the chamber. It’s not part of the combustion process. How does “making chemical changes to the oil” stop LSPI?? If they’re gonna say it reduces friction and therefore heat, I’d say “prove it”. You’ve already got Heat Transfer Fluid (ie “antifreeze/coolant”) circulating to remove heat.

The high octane gas I understand. The oil angle I don’t understand.

Do you have a link that discusses this?
 
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I don’t understand this statement. The oil is not even in the chamber. It’s not part of the combustion process. How does “making chemical changes to the oil” stop LSPI?? If they’re gonna say it reduces friction and therefore heat, I’d say “prove it”. You’ve already got Heat Transfer Fluid (ie “antifreeze/coolant”) circulating to remove heat.

The high octane gas I understand. The oil angle I don’t understand.

Do you have a link that discusses this?



gms reasoning for switching the dexos specs to help with it. wether or not it helped i can’t say but there’s a bunch of info on the net explaining gms reasoning


Sent from my iPhone using Tapatalk
 

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I don’t understand this statement. The oil is not even in the chamber. It’s not part of the combustion process. How does “making chemical changes to the oil” stop LSPI?? If they’re gonna say it reduces friction and therefore heat, I’d say “prove it”. You’ve already got Heat Transfer Fluid (ie “antifreeze/coolant”) circulating to remove heat.

The high octane gas I understand. The oil angle I don’t understand.

Do you have a link that discusses this?
https://www.oronite.com/about/news/low-speed-pre-ignition.aspx

This link explains the LSPI phenomenon about as good as any, as how oil is a factor. It has to do with the calcium content of the oil, and minute amounts entering the combustion chamber, either by deposits or droplets.

Fuel trim is also a factor that contributes along with octane.

There isn't just one cause.

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I read it and I'm not trying to start a debate really...I'm only stating my opinion!

I might just be an old set in my ways 60 yr old hard head but I'm calling that BS and a sales pitch. I've worked long enough in the Technical field to have witnessed data to be used (manipulated) to drive decisions and when influenced enough curves fit into the data that support bunk.

JMHO!
 

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Today's engine use low tension rings on the pistons, that lets a little more oil through into the combustion chamber. Corporate fuel economy standards and the quest to meet them. Not only GM, Honda had a big problem with their motors a few years ago with oil getting past rings. Adding turbo boost into the equation is today's game changer. Want to get into oil then surf Bob is the Oil guy website. Those guys are intense.
 
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