Gas. 87, 91, 93 Octane?

[Todd Piefer]

No sir, and I quote: "Intake valve comparison showing a new valve compared to the results from the 100-hour engine test."

They are saying that after 100 hours (approximating 4,000 of driving), this is how the valve compared to a brand-new one.

Yes, I do see that fine print below the picture now. I'll pay closer attention before posting replies in the future.

 

[Marc Collins]

No offense but this is completely incorrect and I’m amazed at how many people are still ignorant of facts. Without going into a long explanation I’ll try to clarify some misconceptions.

Although higher octane ratings do relate to better knock resistance, it also ties directly to how efficiently the fuel burns when in combustion. Higher octane helps the engine produce power more efficiently, requiring less fuel. This typically will increase fuels economy by 5-10%. Do research and you will see most people get better mileage using higher octane fuels.

Also, not only do higher octanes burn better, they also burn cleaner leaving less carbon buildup in the cylinder, valves, etc. That buildup can cause decreased performance & gas mileage quickly and will get worse overtime. Using lower octane fuels than recommend negatively effects engine performance & reliability. This in turn will continue to hurt fuel economy and potentially cause combustion issues over time.

Lastly, I and many others already save more money getting 5-10% better fuel economy from premium gas than the $6-8 a tank you save using 87. Not only are you not saving any money, your also hurting the efficiency & longevity of your engine...

Facts speak for themselves and anyone following these misconceptions will just have to find out the hard way.

And this is the basic reason why premium fuel is "recommended" by so many manufacturers in so many situations. Why wouldn't they recommend it?

Nevertheless, I'd still like to know what octane was used for the official Stinger power output ratings.

 

[Jenny Wang]

Lastly, I and many others already save more money getting 5-10% better fuel economy from premium gas than the $6-8 a tank you save using 87. Not only are you not saving any money, your also hurting the efficiency & longevity of your engine...

Is this also the case for cars that don't require anything higher than 87? Using 93 would give better gas mileage?

 

[Marc Collins]

Is this also the case for cars that don't require anything higher than 87? Using 93 would give better gas mileage?

Yes. If premium was less expensive (less incremental increase) it would always be the preferred choice. You can calculate yourself what % higher cost it is in your location. In my area, it is as much as 20% higher, but is more typically 12-15%. Even at 12%, the cost increase is far greater than any fuel savings (that are typically 1% at best).

 

[SteveCo]

Is this also the case for cars that don't require anything higher than 87? Using 93 would give better gas mileage?

Generally, NO if regular gas is recommended for that vehicle, YES if premium is recommended but not required (economics aside). Here's a link to a study done by the AAA on using premium fuel in vehicles that do not require it.

https://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

An excerpt:

“AAA’s tests reveal that there is no benefit to using premium gasoline in a vehicle that requires regular fuel,” said Megan McKernan, manager of the Automobile Club of Southern California’s Automotive Research Center. “Premium gasoline is specifically formulated to be compatible with specific types of engine designs and most vehicles cannot take advantage of the higher octane rating.”

And a newer test by the same organization on use in cars where premium is 'recommended'.

https://newsroom.aaa.com/2017/12/dont-fueled-premium-not-always-worth-price/

 

[Marc Collins]

Generally, NO if regular gas is recommended for that vehicle, YES if premium is recommended but not required (economics aside). Here's a link to a study done by the AAA on using premium fuel in vehicles that do not require it.

https://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

An excerpt:

“AAA’s tests reveal that there is no benefit to using premium gasoline in a vehicle that requires regular fuel,” said Megan McKernan, manager of the Automobile Club of Southern California’s Automotive Research Center. “Premium gasoline is specifically formulated to be compatible with specific types of engine designs and most vehicles cannot take advantage of the higher octane rating.”

And a newer test by the same organization on use in cars where premium is 'recommended'.

https://newsroom.aaa.com/2017/12/dont-fueled-premium-not-always-worth-price/

Those are the best, unbiased sources for details around all of this issue that I have seen (the full reports are available for download). Off the cuff, I said above 1% increase in fuel economy versus 12-20% additional cost for premium. The AAA study says 2.7%, but what I didn't realize was the range went from -1.0% to +7.1%. So, even in the most optimistic scenario of a car gaining even more than 7.1%, you'd likely still never even break even.

However, for higher performance cars like the Stinger, there will be people willing to pay 12% - 20% more for fuel to gain power (range was -0.3% to +3.2%, with an average of 1.4%). Everyone can decide for themselves if they are one of those people Unfortunately, without specific testing, we don't know where Stinger is on the spectrum for fuel economy or power gains/losses, and it will also vary by engine.

 

[bugaboo90]

After reading all these latest posts, I've transitioned to going with the 93. Shell and others have cleaners in them which help the engine long term and the higher performance is nice, although I doubt if I'll notice. In the old days there was a $0.10 difference between grades, when did the difference before do big. Lol

 

[NYLAWBIZ]

How about the ethanol content? does anyone care about its effects of the fuel injection system?

 

[SteveCo]

How about the ethanol content? does anyone care about its effects of the fuel injection system?

The owner's manual states that the fuel system is tolerant of up to 10% ethanol, which is a standard fuel blend. It also specifically states that the car is not compatible with E85, which can cause fuel system damage.

I try to purchase pure gasoline where I can find it, as alcohol contains less energy than gasoline - a given volume of alcohol blended fuel is going to give less power and decreased mileage. See pure-gas.org.

 

[StungBlueGT2]

Is this also the case for cars that don't require anything higher than 87? Using 93 would give better gas mileage?

In general yes, and even more so if 91+ is "recommended" but not required. All cars will benefit from higher quality, higher octane fuels. However, as others have stated the amount of benefit varies on many factors. The most significant factor being forced induction vs. natural aspirated engines. A N/A engine requiring 87 will see a minimal increase, while a boosted engine like our Stingers will see 5-10%(up to 7.1%=AAA) better fuel economy.

 

[GTB]

Dyno and 1/4 will prove all

 

[Berzerker]

If anyone has a Costco near them, try to compare gas prices and see if the $30 $60 membership is worth it for you. For me, Costco premium around me is about 30c cheaper than the cheapest Shell or BP around me, which equates to around $130 saved/year, so that $30 $60 goes a long way. And since they're Top Tier, you don't need to worry about fuel quality.

Edit: Costco Membership is $60 not $30, I split it with a friend (you can have 2 people on the membership), which is where I got $30 from.

 

[StungBlueGT2]

Those are the best, unbiased sources for details around all of this issue that I have seen (the full reports are available for download). Off the cuff, I said above 1% increase in fuel economy versus 12-20% additional cost for premium. The AAA study says 2.7%, but what I didn't realize was the range went from -1.0% to +7.1%. So, even in the most optimistic scenario of a car gaining even more than 7.1%, you'd likely still never even break even.

However, for higher performance cars like the Stinger, there will be people willing to pay 12% - 20% more for fuel to gain power (range was -0.3% to +3.2%, with an average of 1.4%). Everyone can decide for themselves if they are one of those people Unfortunately, without specific testing, we don't know where Stinger is on the spectrum for fuel economy or power gains/losses, and it will also vary by engine.

I also agree that this is a very informative article and gives a good average baseline of increases to power & fuel economy. However, the comparisons between fuel cost and increased economy using percentages are a little deceiving. These are completely separate values and cannot be related using percentages. Lets break this down to see what actual savings may come from these differences.

Comparison based on AAA values & EPA using 87 as baseline:
87 fuel-15 gallons@$3.00/g=$45.00
93 fuel-15 gallons@$3.50/g=$52.50
Approximate savings of $7.50
EPA combined mileage-21mpg=21x15g=315miles/tank
EPA combined mileage-21mpg+2.7%(avg gain using 93)=21.6x15g=324m
EPA combined mileage-21mpg+7.1%(max tested gain using 93)=22.5x15g=338m
These results seem conservative and will probably be higher for turbocharged cars geared for more performance. My and others personal experience with Optima & Stinger gained 5-10%mpg using 93. 21mpg+10%=23.1x15=347m

That means that avg gain of 9miles/tank would be 41% of a gallon or $1.44 off the $7.50=$6.06/tank savings.
Max AAA gain of 23miles=110%gallon or $3.85-$7.50=$3.65/tank.
Max customer gain of 32miles=152%gallon or $5.32-$7.50=$2.18/tank.

Estimated savings using 87 ranges from about $2-$6 per tank, or only 3.8%-11.4% less cost, not the 12-20% difference stated above.

Nothing personal and no offense to anyone, but I cant understand how this is even a debate. Why buy a $50k performance car, but then fill it with cheap fuel that negatively effects economy & power? This is like an Olympic athlete eating junk food before an event just because a high protein/low fat diet wasn't "required" and could save them a few dollars. I agree that they could survive on poor quality foods, but doesn't that defeat the purpose and intention of being an athlete?

Maybe I'm missing something, but can anyone explain why a person that is trying to pinch pennies would get an expensive performance car that only gets 20mpg?

Lol, sorry all and just realized I really fell off my soapbox...

 

[Berzerker]

I also agree that this is a very informative article and gives a good average baseline of increases to power & fuel economy. However, the comparisons between fuel cost and increased economy using percentages are a little deceiving. These are completely separate values and cannot be related using percentages. Lets break this down to see what actual savings may come from these differences.

Comparison based on AAA values & EPA using 87 as baseline:
87 fuel-15 gallons@$3.00/g=$45.00
93 fuel-15 gallons@$3.50/g=$52.50
Approximate savings of $7.50
EPA combined mileage-22mpg=22x15g=330miles/tank
EPA combined mileage-22mpg+2.7%(avg gain using 93)=22.6x15g=339m
EPA combined mileage-22mpg+7.1%(max tested gain using 93)=23.6x15g=354m
These results seem conservative and will probably be higher for turbocharged cars geared for more performance. My and others personal experience with Optima & Stinger gained 5-10%mpg using 93. 22mpg+10%=24.2x15=363m

That means that avg gain of 9miles/tank would be 41% of a gallon or $1.44 off the $7.50=$6.06/tank savings.
Max AAA gain of 24miles=109%gallon or $3.82-$7.50=$3.68/tank.
Max customer gain of 33miles=150%gallon or $5.25-$7.50=$2.25/tank.

Estimated savings using 87 ranges from about $2-$6 per tank, or only 3.8%-11.4% less cost, not the 12-20% difference stated above.

Nothing personal and no offense to anyone, but I cant understand how this is even a debate. Why buy a $50k performance car, but then fill it with cheap fuel that negatively effects economy & power? This is like an Olympic athlete eating junk food before an event just because a high protein/low fat diet wasn't "required" and could save them a few dollars. I agree that they could survive on poor quality foods, but doesn't that defeat the purpose and intention of being an athlete?

Maybe I'm missing something, but can anyone explain why a person that is trying to pinch pennies would get an expensive performance car that only gets 20mpg?

Lol, sorry all and just realized I really fell off my soapbox...

Good comparison, but if you're going to be commenting on buying the GT2, you should use the 21MPG number, and the fuel tank capacity is 15.9gal, close to 16.

It's a straight number swap, so the percentages should be similar, but just something to consider.

 

[+StingerGT2]

92 Octane for me

 

[StungBlueGT2]

Good comparison, but if you're going to be commenting on buying the GT2, you should use the 21MPG number, and the fuel tank capacity is 15.9gal, close to 16.

It's a straight number swap, so the percentages should be similar, but just something to consider.

Good catch and corrected the MPG in my original post, but the percentages did stay the same. Also, I left the fuel capacity for comparison to about 15 gallon since most people refill before completely running out of gas.

 

[davebo]

Nothing personal and no offense to anyone, but I cant understand how this is even a debate. Why buy a $50k performance car, but then fill it with cheap fuel that negatively effects economy & power? This is like an Olympic athlete eating junk food before an event just because a high protein/low fat diet wasn't "required" and could save them a few dollars. I agree that they could survive on poor quality foods, but doesn't that defeat the purpose and intention of being an athlete?

Maybe I'm missing something, but can anyone explain why a person that is trying to pinch pennies would get an expensive performance car that only gets 20mpg?

I appreciate all the math you put into the post, and your comparison to an Olympic athlete works when we're at the track or driving aggressively on public roads, but it's not so apt when people are facing a long highway road trip or boring commute to work. A better analogy would be an Olympic athlete having a cereal bar for breakfast instead of a properly cooked and nutritionally balanced meal on a day that they have nothing special planned at all, maybe just a routine workout.

As for who would buy the Stinger then put regular gas in it to save money, I guess anyone who was considering the Buick Regal GS but thought it had too little power, and there weren't any other liftback sedans available in that price range with 320-350hp. That's the sort of gap in the market Kia was here to fill, but within any market gap there's gonna be some wiggle room. You could just as well ask why anyone is putting LAP3 chips to get their Stingers over 400hp instead of just buying a faster car to begin with. I imagine the reasons are numerous.

 

[LeoDragon]

91 for me.

 

[SteveCo]

Nothing personal and no offense to anyone, but I cant understand how this is even a debate. Why buy a $50k performance car, but then fill it with cheap fuel that negatively effects economy & power?

No offense taken, but at my local Shell filling with premium (in liters) adds 12 dollars to the fuel bill. If I'm going to be driving in the mountains, enjoying a Sunday drive on secondary roads, or testing the car's limits on an autocross, I'll pay the extra. If I'm going to be on cruise control on a primary highway for a few hundred kilometers or putting around town, chances are good I'm going to fill with regular. Nice to have a choice - the car is fine with it, and so am I ...

 

[davebo]

No offense taken, but at my local Shell filling with premium (in liters) adds 12 dollars to the fuel bill. If I'm going to be driving in the mountains, enjoying a Sunday drive on secondary roads, or testing the car's limits on an autocross, I'll pay the extra. If I'm going to be on cruise control on a primary highway for a few hundred kilometers or putting around town, chances are good I'm going to fill with regular. Nice to have a choice - the car is fine with it, and so am I ...

I guess the one benefit to a car that gets poor mileage coupled with a tiny gas tank, is we have plenty of opportunities to switch fuel based on our anticipated use that week.