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I have a 2012 Volt that was new and have always used premium gas but I've been told by other Volt owners that they switched to regular and have had no issues. What do you think?
 

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Depends on how crappy regular is in your area. In general, a modern engine control system can adjust for variations in octane. Expect an mpg hit if there is a lot of difference.

Keep in mind that the posted octane is the minimum. Octane may be much higher than posted.

Due to availability, I have occasionally had to use regular in my ELR. No obvious ill effects for a tank here or there.

The ‘05 HEMI I had was way pickier. Regular made it run very rough.
 

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The “Top Tier” gasoline’s are supposed to be better quality and retain good qualities while sitting for sometimes months in your tank. I have used regular, mid grade, even experimented with non-alcohol gasoline on road trips. Found they all work fine. You can judge an individual tankful by resetting your trip indicator and watching the real time fuel mileage calculation. Here in Michigan now that the better quality summer blend gas is being sold, everybody’s mileage goes up a tad.
 

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Not a good idea.

I've seen the data. You can't hear it or feel it but the knock sensor is working overtime on anything less than premium. Usually pulling out -6 degrees or more of timing. That means your engine is in serious danger. The sensor responds to knock, which means you already are in detonation.

I'll post a screen shot of one of my logs a little later.
 
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Discussion Starter #5
But the newer volts are setup to run on regular gas does this mean that something changed in the engine for the fuel injection system?
 

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The newer Volts have variable valve timing to compensate for low octane fuel. The older Volt can only adjust ignition timing.
 

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But the newer volts are setup to run on regular gas does this mean that something changed in the engine for the fuel injection system?
The engine is totally different between Gen1 (1.4l) and Gen2 (1.5l). Gen2 is specifically tuned to use regular. Using premium in the Gen2 is a waste of money.
 

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If you look on this forum there were some discussions in the past about this.
The conclusion I came to on it is, the Gen 1 motors run at a higher compression and are tuned to premium fuel.
If you run regular fuel in it, it won't blow up your motor because the computers try to compensate, but expect about a 10% drop in mileage efficiency.
In my case I like staying with the recommended fuel, the premium fuels tend to be available with no ethanol which is a better fuel to have in the tank if it is going to sit in there for a long time because you are running mostly electric.
And the price versus efficiency is about a wash, so at that point why stray off from the recommended fuel?
 
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In my area the premium fuel normally runs a drastic price premium (often 25-30%) compared to regular. It's not unusual to see regular at 2.69 and premium 3.39+. I've also seen about a 10% reduction in efficiency using regular 87 octane. It would probably be cheaper to operate the Volt on regular fuel here even with a 10% drop in efficiency but I would still use premium. Why?

First off, the Volt uses so little fuel anyway that the cost difference is literally a few dollars a month at most. Second, as fuel ages the octane rating goes down, so theoretically premium fuel would stay usable longer than regular. This might actually be a concern in the Volt if the extended range driving is not often used.
 

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I've been using 87 octane almost exclusively the last year or so. 91 is only available at a handful of stations around here (typical 87, 89, 93) and 93 is usually about $.50 more per gallon. I think the fuel economy is decreased a little bit, but I don't think it's anywhere near the 20% cost difference.
 

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I have a 2012 Volt that was new and have always used premium gas but I've been told by other Volt owners that they switched to regular and have had no issues. What do you think?
My son is driving a G1 and moved a while back to be 1/2 between his wifes work and his work. He burns gas daily but dramatically less gas. With that driving he also did the comparison of using premium gas (better MPG) and regular (less MPG) and determined regular was saving him money.

Honestly, I now don't think it matters if you use regular. I think one reason premium was used was so they could PR talk up the MPG numbers.
 

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I buy about 50 gallons of fuel a year, even doing the road trips that I do. That's about $30 a year extra for the 91 octane. Some people change their oil every year because leaving it for two makes them worry, and that probably cost them at least $30.
 

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The gen1 volt does have variable valve timing. also called cam phasing, to assist in low speed torque. I have been running 87 exclusively for the last 10k miles, I typically use 2gal per day. FE is around 35 on a bad, cold, windy day up to 44 under good conditions. http://ecomodder.com/forum/em-fuel-log.php?vehicleid=10178

Think about it, premium gave more mpgs and this car was sold on efficiency. They HAD TO require premium to ensure the EPA tests showed the best FE.
 

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The gen1 volt does have variable valve timing. also called cam phasing, to assist in low speed torque. I have been running 87 exclusively for the last 10k miles, I typically use 2gal per day. FE is around 35 on a bad, cold, windy day up to 44 under good conditions. http://ecomodder.com/forum/em-fuel-log.php?vehicleid=10178

Think about it, premium gave more mpgs and this car was sold on efficiency. They HAD TO require premium to ensure the EPA tests showed the best FE.
As I recall GM also claimed that premium gas was more stable, did not degrade as quickly as regular gas in the fuel tank. This was considered important given that most Volt drivers use so little gas.
 

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GM claims in owner's manual that using lower octane can result in engine damage (most manufacturers claim it will result in reduced performance).

Does someone have source where variable valve timing is on Gen 1? I was unable to find anything while looking.

I was able to find this 2008 article that mentions both intake and exhaust are variable. https://www.autoblog.com/2008/09/26/tech-analysis-of-gms-new-1-4l-four-cylinder-engine/

That gives me some hope it could adjust enough to prevent damage, but GM is oddly specific not to run low octane.
 

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This is one of my logs on 87 octane. It scared the crap out of me, and I'll never run 87 again. Notice the box to the right. Full of red. Red is bad. This indicates timing pulled due to the knock sensor losing it's mind.

Screenshot (23).jpg
 
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