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Discussion Starter · #1 ·
I searched around and couldn't really find any posts about this so I thought I'd ask the question. What are you running for fuel, regular or premium?
 

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Regular. IMHO, premium would be a waste of money.
 

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If you run anything more than what's recommended in the owner's manual, you're wasting money and maybe getting less economy.
 
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Discussion Starter · #6 ·
Yea I know what the owners manual says I was just wondering what people were actually running.
 

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I'd like to see what the 3.6L does timing-wise with regular vs premium. My guess is "nothing interesting" ... but on the LTZ in my Colorado the difference is dramatic. However the LTZ is pretty modern by comparison (which has both pros and cons).
 

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For many engines regular is recommended, does not mean that premium is not better for performance. I run premium and I don't have a heat problem, no ticking at start, and my oil cooler has not leaked,, LOL. But my MPG sucks at about 12-13 average because of how and where I drive, not to mention lift, tires, and added weight.
 
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Regular and Premium require different ignition timing. If you have a tuner and can tune for Premium fuel you will see better mileage and better performance. If you don’t have a tuner and run Premium on a factory tune you will likely see poorer fuel economy however it my run smoother as it is a higher grade fuel with no ethanol.
I use to run Premium with a tune in my 2008 3.8L and that made a huge difference over 87 regular and the factory tune.


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I had the 3.8, now 3.6 and have used regular in both. Figured i wouldnt see enough performance or fuel mileage gain to justify the near 20 percent hike in cost around here, but wouldnt be surprised if that new 2.0L required premium.
 

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I had the 3.8, now 3.6 and have used regular in both. Figured i wouldnt see enough performance or fuel mileage gain to justify the near 20 percent hike in cost around here, but wouldnt be surprised if that new 2.0L required premium.
Yupp, 2.0 requires 91 minimum.
 

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Ethanol is a simple fact of life, beside being a oxygenator it is also a octane booster. The days of non-ethanol fuel are slowly going away.

Unless you have a tuner that calls for a specific octane run what is in the manual. If you are pinging or knocking you need to have the issue corrected as this should not happen on an otherwise healthy engine.
 
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Mine seems to hold 5th better on the freeway with 91. But it's probably just in my head.
 
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Mine seems to hold 5th better on the freeway with 91. But it's probably just in my head.


It probably does feel like more pull. Higher octane brings higher Ftlbs torque, especially when tuned for it.

My old Dodge truck manual suggested running premium when towing..


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99% of the premium gas sold in the US has just as much ethanol as the lower octane fuel marketed by the same co. Premium fuel is determined By the octane not Ethanol content.
The tier rating is determined by the detergent additive package by the distributor at the tank farm. The fuel from the refiner's to the farm in most cases all comes through the same pipe line and is graded , blended and sorted at the farm. You can choose to buy Ethanol free gas if it is available in your area but you will pay more. Ethanol is just an additive to reduce emissions
 

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It probably does feel like more pull. Higher octane brings higher Ftlbs torque, especially when tuned for it.

My old Dodge truck manual suggested running premium when towing..


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The word is only if it is tuned for it. Higher octane fuels have a slower burn allowing for more timing. It is the addition of timing that gives us more power. Unless more timing can be added there is no improvement on power. I left out compression because it is fixed.


Now there are some unknowns when it comes to our engine. From just watching my instruments I know this engine rides on the knock sensors, meaning it is adding as much timing as the program will allow. I also know the amount of timing you can have is based on IAT, which down here is always above 100 so max timing has been pulled.

The question being does the program allow for more timing if not on the knock sensor even though IAT is high. If it does then there would be more power available running a higher octane fuel.
 

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I’ll ask another similar question. Would it be worthwhile to put a tank of ethanol free gas in my 3.6 every few months?

Local QT and Racetrac’s sell it but it’s not cheap.


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