Premium vs Regular Fuel

[Jmlo96]

Not driving TourX since last year, but it does run better on 91. But if only 5% difference in mileage that is not gonna cover the spread in price.
I have been burning regular in LS3 in G8 and it seems to run fine on it. Much easier to not mind power loss when you have plenty to start with.

Gas mileage and power aren’t necessarily my primary concerns. When these LTG 2.0 turbos were released in Cadillacs, GM had tons of problems with the pistons melting due to low speed pre ignition. If the computer is pulling timing, that means it’s actively pulling timing to hopefully prevent damage from occurring to the motor. GM seems to have fixed the issues with these motors but I personally would rather not find out the hard way.

 

[autocomman]

They will ping at low rpm still to the point where you can hear it, even with premium. Proof is in the pudding. Retarding timing even just a few degrees makes a big difference in overall performance and efficiency. Pulling 7 degrees is quite substantial. There are limits as to how much timing the ECU will pull....so you may now be able to overcome the low octane at a certain point, at that point you will start to damage things.

This is an argument people will always have, it runs fine on regular....well I can twist and tape an extension cord together from bits of wire. It works fine. Is it a great idea? There are people who wouldn't care, and people that would go, well not so much

 

[L J]

Gas mileage and power aren’t necessarily my primary concerns. When these LTG 2.0 turbos were released in Cadillacs, GM had tons of problems with the pistons melting due to low speed pre ignition. If the computer is pulling timing, that means it’s actively pulling timing to hopefully prevent damage from occurring to the motor. GM seems to have fixed the issues with these motors but I personally would rather not find out the hard way.

Had a 15 ATS with 272 hp turbo 4 I traded on TourX.
I assume the TourX with 250 hp version is less stressed then Caddy version so melting pistons probably not issue unless you mod to over 500 horses, that they say is not a problem.

 

[adam728]

Can't beat real world technical results. That's a pretty significant jump. What types of temperatures were you seeing when this was occurring? If this was in cooler weather, I can only imagine what would happen with higher heat.

Definitly in colder temps, it was during Thanksgiving to Christmas time in Michigan.

 

[jmf432]

I've run both 89 and 93. Ran 89 a couple winters ago to see how it would handle. Definitely noticed a loss in performance and anywhere from a 5-10% drop in fuel economy. Back to 93 now all the time since it's not that much more at Costco than 89 and at current prices basically pays for itself in the fuel economy gain.

 

[L J]

GM may not be the brightest bulb in the pak but
if they thought regular fuel was a problem on damaging a engine, they would say premium required.. not recommended for best performance.
PS Like with GM tune on my coupe they supplied prem required sticker for fuel flap.

 

[adam728]

Gas mileage and power aren’t necessarily my primary concerns. When these LTG 2.0 turbos were released in Cadillacs, GM had tons of problems with the pistons melting due to low speed pre ignition.

Had a 15 ATS with 272 hp turbo 4 I traded on TourX.
I assume the TourX with 250 hp version is less stressed then Caddy version so melting pistons probably not issue unless you mod to over 500 horses, that they say is not a problem.

500 hp? I think the limit on stock pistons/rods is MUCH lower than that.

The problem isn't so much that these are tuned to the bleeding edge of power. Rather, they are set to operate for best emission and fuel economy. Gasoline engines are most efficient when throttling losses are low. This means, in general, that it's almost always better to be in the tallest gear possible, with the throttle open more to reach the power necessary for the situation. This is why stock the TourX seems to always want to go straight to 8th gear and never leave. Best fuel economy. Watching may car I've seen it lug along at like 1200 rpm in 8th, but with the throttle body at wide open going up a mild hill. Pedal was FAR from the floor, but rather than downshift and use like 30-40% throttle, it will run 100% throttle and lug. Better fuel economy.

What's not better is the opportunity that opens up for detonation or low speed pre ignition. You have a high charge density in the cylinder, and lots of time (relatively) for things to heat up and go boom too soon. The time factor is a big one. You are far more likely to run into engine damaging uncontrolled combustion (detonation or preignition) at low rpm rather than high. And while the engine's not in a greatly stressed state of tune, the transmission strategy puts it in one.

 

[L J]

GM has had almost no issues with engine damage with 87 octane fuel, now if you put 85 octane farm gas in it in Utah maybe.

 

[Jmlo96]

I used to work at a Cadillac dealer back in 2016 and stock ATS and CTS with the 2.0 turbo were coming in with melted pistons. GM contended that LSPI based on the Dexos 1 Gen 1 standard was a partial contributor. Thus, where the Dexos 1 Gen 2 standard came from. GM claims to have fixed the problem but I'd be willing to be that a large number of those impacted vehicles were running 87 octane fuel rather than the recommended 91 octane.

 

[L J]

GM may not be the brightest bulb in the pak but
if they thought regular fuel was a problem on damaging a engine, they would say premium required.. not recommended for best performance.
PS Like with GM tune on my coupe they supplied prem. required sticker for fuel flap.

 

[L J]

Plus they have to consider all variables involved, they sure don't want to pay a shitload of high priced warranty claims.

 

[L J]

I used to work at a Cadillac dealer back in 2016 and stock ATS and CTS with the 2.0 turbo were coming in with melted pistons. GM contended that LSPI based on the Dexos 1 Gen 1 standard was a partial contributor. Thus, where the Dexos 1 Gen 2 standard came from. GM claims to have fixed the problem but I'd be willing to be that a large number of those impacted vehicles were running 87 octane fuel rather than the recommended 91 octane.

I guess buying a new Syclone is off the table, since going out of state to get 93 octane required pump gas may be a problem.

 

[saab93driver]

Lots of cars with this engine (including the Regal) are in the rental fleets and you know those folks aren't filing up with premium, even before gas prices went crazy. Past teething pains for this engine aside, if it were an ongoing issue today I think there'd be a lot more posts about melted pistons and broken engines.

 

[L J]

Hope power companys dont start charging a premium for 220 over 110 when we are charging vehicles, if I actually buy one.

 

[L J]

Lots of cars with this engine (including the Regal) are in the rental fleets and you know those folks aren't filing up with premium, even before gas prices went crazy. Past teething pains for this engine aside, if it were an ongoing issue today I think there'd be a lot more posts about melted pistons and broken engines.

No shit Sherlock..
I mean KimoSaab93...

 

[saab93driver]

No shit Sherlock..
I mean KimoSaab93...

Nice...

 

[L J]

Nice...

Thanks
That could be the nicest thing anyone has texted me.

 

[adam728]

Lots of cars with this engine (including the Regal) are in the rental fleets and you know those folks aren't filing up with premium, even before gas prices went crazy.

While I haven't traveled much since 2020, I did a LOT prior to that. Can't say I have ever seen a Regal at National/Hertz/Enterprise. Don't know on others. And I've certianly not stumbled on a 2.0T Malibu or Equinox, only their smaller engined brethren.

 

[L J]

While I haven't traveled much since 2020, I did a LOT prior to that. Can't say I have ever seen a Regal at National/Hertz/Enterprise. Don't know on others. And I've certianly not stumbled on a 2.0T Malibu or Equinox, only their smaller engined brethren.

No doubt they have a short rental career.
Dam idiots burning cheapest fuel they can find, while driving it like they stole it....
I mean drove it like a rental.
I am sure GM has powertrains pretty idiot proof.
PS A friend did say they rented a 2.0T Terrain.

 

[saab93driver]

While I haven't traveled much since 2020, I did a LOT prior to that. Can't say I have ever seen a Regal at National/Hertz/Enterprise. Don't know on others. And I've certianly not stumbled on a 2.0T Malibu or Equinox, only their smaller engined brethren.

Herts shows Regal, Malibu, Camaro, CTS Caddy, all with the 2.0L turbo engines.

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