Gas. 87, 91, 93 Octane?

[Marc Collins]

I only use 94. Very obvious mileage gains with 94. The odd time I’ve been forced to fill up with 91 I burn through the fuel noticeably faster.

Avg 9.8L/100km @94
Avg 11L/100km @91

Not sure if this can be verified by anyone else but I keep a log on Fuelly and have definitely noticed a difference.

Sorry, but there is close to zero chance a mileage difference of that magnitude is a result of only that octane change.

 

[bugaboo90]

I get what you are saying about going to 87 during winter and get the idea of a couple of hundred bucks ( assume $0.50 cost difference, assume 20 gal/wk, assume 16 wk of winter = 200ish dollars..) But, I wonder if saving 200 is worth the "wear" you get on your engine for 1/3 of the yr. I'm not a car guy at all but love this car... I go back and forth about 87 vs 91... I think I'll stick with 91 but may drop to 87 since costco is a drive for me sand i tend to stay home more during winter.

Most of Canada is cold and requires winter tires and a change in driving behaviour for half the year. There’s no way I’m going to use the vehicle’s peak performance during this time.

There’s a significant gap in price between 91 and 87 octane, so an incentive exists to use a lower octane if possible.

I’ve been gradually experimenting with blending octanes of Top Tier gas until I was down to pure 87. And I have to say, my butt doesn’t notice any difference in performance.

I think I’ll use 87 all winter. Figure I’ll save a couple hundred dollars.

I’ve been using 91 octane for the past decade in my previous car. I’m sure there’s a calculable performance difference, I just can’t tell when driving it.

 

[SilverNitr8]

I get what you are saying about going to 87 during winter and get the idea of a couple of hundred bucks ( assume $0.50 cost difference, assume 20 gal/wk, assume 16 wk of winter = 200ish dollars..) But, I wonder if saving 200 is worth the "wear" you get on your engine for 1/3 of the yr. I'm not a car guy at all but love this car... I go back and forth about 87 vs 91... I think I'll stick with 91 but may drop to 87 since costco is a drive for me sand i tend to stay home more during winter.

The car was designed to run on 87 so if you are concern about the wear, I highly suggest you stick to a top tier gas. That's a proven fact that top tier gas prolongs wear and tear on your engine. Dont confuse top tier gas with octane number. They are different. What I'm referring to is Shell vs. 7-11 gas.

 

[bugaboo90]

OHHH I thought top tier only applied to premium gas octane.

Is shell and costco 87 octane top tier?

The car was designed to run on 87 so if you are concern about the wear, I highly suggest you stick to a top tier gas. That's a proven fact that top tier gas prolongs wear and tear on your engine. Dont confuse top tier gas with octane number. They are different. What I'm referring to is Shell vs. 7-11 gas.

 

[SilverNitr8]

OHHH I thought top tier only applied to premium gas octane.

Is shell and costco 87 octane top tier?

Here's the article about it and yes both are on the list. They are specific to the brand, not the octane so an 87 shell is also top tier. A 91 octane 7-11 gas is not.

Study Shows Top Tier Gasoline Worth the Extra Price

Full list of top tier gas stations
Top Tier Detergent Gasoline - Wikipedia

 

[CDv6]

Full list of top tier gas stations
Top Tier Detergent Gasoline - Wikipedia

Top Tier is a licensed fuel standard, so it's probably best to use their official list of licensees, rather than relying on unknown edits from Wikipedia.

 

[twig2121]

interesting posts. I've had turbo cars for the last 20yrs so 93 octane is natural for me.

If you buy a nice (and special) vehicle like the stinger, you definitely shouldn't cheap out on the fuel. It'll make more power and keep the engine cleaner. Go with highest octane in your area and top tier - simple as that! If you can't afford a couple extra dollars to maintain your car, you have the wrong car and re-evaluate your life choices.

I just returned from a trip to iceland and although fuel was 3X more expensive than here (we really should stop complaining), they only had Diesel OR 95 octane. This thread wouldn't even exist in iceland! We did have a Kia rental - diesel sportage...

 

[davebo]

I'm gonna go ahead and disagree. Top Tier is of course proven to keep the engine cleaner, yes. Whether people want to spend X dollars per gallon Y months of the year for Z amount of additional horsepower is entirely up to them, and doesn't make them cheap or mean they have the wrong car, which is ludicrous of you to assume.

 

[Clearly Canadian]

You’re welcome and I understand your analogy, but that version is missing half my point. A cereal bar is somewhat healthy and probably would still be part of their “recommended” diet. That would be like running mid grade 89 octane at least. I’m only talking about users of lower quality 87 octane that insist on ignoring manufacturers recommendations. 87 almost always has less additives(leaves 19 times more carbon buildup)and will negatively effect engine performance, efficiency and longevity. I feel this equates to a closer comparison of an athlete "occasionally" eating junk food which would still have those compounding negative effects, especially over repeated uses.

The fact is that our Stingers were built to run on premium fuel. Just because the ECU has the ability to protect itself from poorer fuel and retard timing doesn’t mean it should be used that way. This is simply a defense mechanism of the engine management system, and NOT how it was designed to operate. IMO you shouldn’t purposely go against manufacturers recommendations and potential cause combustion issues just because its possible.

In reference to the the Buick GS, I think you may have misunderstood the point of my question. I agree there is a wide market gap the Stinger is covering and there are less powerful alternatives to the Stinger. However the Buick GS is still designed as "GrandSport" performance car with priorities focused on power, not economy. If saving a few bucks on fuel was a deciding factor, then why not get a more economical car like the 2.0L Stinger?

Again no offense to anyone, but I just dont understand the purpose of paying $6k-$20k more to get a high performance 3.3TT, but then try to save a few bucks using fuel that negative effects the performance you paid extra for in the first place.

Mysteries of the universe I guess and just trying to help educate people on the negatives of 87 octane so they don't create future problems for themselves.

Another informative video from Engineering Explained.

 

[SilverNitr8]

Another informative video from Engineering Explained.

Great information to sum things up.

 

[NOBODY]

All modern cars will adjust timing to prevent engine damage as you switch from one octane to another.

The question that is important to get a confirmed answer is whether the power and torque ratings of the car are valid with 87 octane gas. If so, great and you will get a nice boost if you use higher octane. If the car is "recommended" to use premium/91 or higher octane just to achieve the advertised power numbers, then that is a different story. Most European turbos require premium to get the advertised numbers.

totally agree

 

[Manchuz]

I only use 94. Very obvious mileage gains with 94. The odd time I’ve been forced to fill up with 91 I burn through the fuel noticeably faster.

Avg 9.8L/100km @94
Avg 11L/100km @91

Not sure if this can be verified by anyone else but I keep a log on Fuelly and have definitely noticed a difference.

I can't verify this but I did notice a similar fuel economy difference between 87 and 91 - on 87, it burned through the fuel noticeably faster. Maybe I'll try using 94 on my next fill up and do that for a few months and see what kind of fuel economy I get. I've been using 91 for the past 7 months so I know what fuel economy I get given my commute pattern.

 

[Marc Collins]

I can't verify this but I did notice a similar fuel economy difference between 87 and 91 - on 87, it burned through the fuel noticeably faster. Maybe I'll try using 94 on my next fill up and do that for a few months and see what kind of fuel economy I get. I've been using 91 for the past 7 months so I know what fuel economy I get given my commute pattern.

Unfortunately the change in temperature between the two tests will reduce your accuracy significantly...as in so much that the test will not be worthwhile unless you do continuous testing all year round for several years and can then weather-normalize your findings.

It would be much easier to assume little to no difference in economy (1% to 2%) (see video above) and accept that you are investing in higher octane because you think there might be a performance gain. Until KIA releases information, or the car gets included in a comprehensive test like in the video, it's just guesswork and people here can argue back in forth until they are all blue in the face. There could be no impact, or a reasonable impact--no one knows yet and no one's anecdotal tests will reveal anything because conditions are not constant and the tests don't last long enough.

The only thing we do know is that, at best, higher octane will give a few (low single-digit) per cent more HP. If there is a hp gain, it may or may not be accompanied by a fuel economy gain. If there is an accompanying fuel economy gain, it will not be offset by the higher cost of the higher octane fuel. Therefore, the only reason to invest in higher octane is if you need the performance gain (that may or may not exist or may be 0.5%), which could be the case if you were taking your car to the track or pulling a trailer. I think that most reasonable people will agree that commuting to work in northern North American winter conditions does not constitute an urgent need for more than 365 hp. Otherwise, people can feel free to spend more to get zero or a small increase in power (hopefully the Stinger is not like the vehicles in the video that got worse performance with premium!!!) as they choose. No need to try to justify it with impossible economics about fuel economy.

 

[SteveCo]

IMHO, any possible marginal gains in fuel economy aren't going to even come close to offsetting the fuel price on premium gas, especially in Canada. As far as detergent additives in the fuel, all top tier gas has them - any additional benefits in the premium gas package still won't address my main concern in a GDI engine, which is deposit accretion on the back side of the valves.

That's going to require a Seafoam or similar cleaner application run through the intake. KIA has a product they use for this, which is part of the maintenance schedule.

 

[StungBlueGT2]

Another informative video from Engineering Explained.

Great explanation. He reinforces some of my points and gives a few things to consider that are much more relevant to our Stingers.

First, he shows how higher octane fuel will produce more power which means you can use less fuel for equal performance/acceleration.

Second, he shows that advancing timing increases power and new engines advance/decrease their timing based on knock which is directly tied to octane.

Lastly, the power gains were more significant over the whole powerband opposed to just peak power differences. Power under the curve is the most important!

You have to understand that all of these factors are much more significant to our high performance tuned twin turbo engines. There isn’t another similar engine tested by AAA however the closest comparisons showed the most dramatic gains.

The F150 3.5T is the closest overall and the Mustang & Escalade V8s are more performance orientated. The F150 & Mustang both saw up to 8% better MPG and the Escalade saw almost 15%! The F150 gained 11HP and Mustang 9HP or 4.3% increases.

I believe our advanced DI 3.3TT would have similar if not better results than listed above. Using EPA estimates that would mean almost 3/4mpg city/hwy improvement and conservative 10-15HP difference just by using premium! For a 16g tank that’s 48/64mile gain or a 2-4gallon savings depending how aggressive you drive. That’s almost a $8-$16/tank savings using premium and basically offsets any extra you pay vs regular.

I know these are all just rough estimates but I don’t understand going against manufacturers recommendations to lose 10-15HP and not really see much cost savings. Using anything less than premium fuel shouldn’t even be a discussion on a $50k high performance twin turbo GT, but to each their own..

 

[Ucinn]

My first tank that the deale filled up with, I got just over 19 MPG, I have been using 93 since that tank and have never ha below 22. Also you can definitely tell the difference in power on the butt dyno.

 

[Waynerm002]

I’ve been using the highest octane fuel I can get in my cars over the years, since my BMW 535 (turbo 6) developed some engine issues which they contend might be due to bad fuel. Did I purchase gas from Shell or other top tier brands all the time? No. I would look for the cheapest place with premium (91 at least) and get it there. My in car fuel economy meter would register 24.7 after a week of driving my 60 mile or so daily commute, staying in Comfort or ECO mode. It I still now down to 23.5 since my buddy picked up his car and we have been doing some weekend drives with me flooring it in Sport mode at times. I only use 93 in the Stinger and do most of my fill ups at Costco, although I have found “pure” gas (93 octane) out in Winchester and filled up twice out there when the car was in for service. My 50+ mile one way trip back netted an average of 29 mpg on the in car computer, taking different routes back when I got the “pure” gas.

For me, i’ll stick to the highest octane I can find (not race fuel, but i’d love to mix in some 100 octane) for my cars, Stinger for sure only gets the highest. I know the Optima hybrids felt better with 93 over 87 and I got more miles out of the tank when driving economical and better response when flogging it. Might just be in my head but it does perform better to me. These debates come up from time to time and knowing what the potential cost would have been if I had to pay to fix that BMW engine, i’ll stick with the top tier gas and the best oxtail I can get for my cars.

 

[MerlintheMad]

Count me in the "best for my car" camp. I put UHP "Y" tires on my car because I want the pleasure of knowing that its (potential) performance is not in any way restricted by less capable tires. And HP is the same thinking. Enough car guys say that higher octane (top tier) gas is better for the engine over time. And now this resurrected thread resurrects the debate between "no real benefit to mileage or HP" and "10% to 15% gains". Does anybody really know? Is the argument between cars more than octanes? Unless somebody can show that the Stinger "doesn't care", I will continue to buy the gas that might benefit the engine, rather than the gas that might be inimical to the engine over time.

 

[davebo]

Well that Engineering Explained video was about as much of a controlled environment with scientific results as you could ask for, but obviously since it didn't include the Stinger GT no one can say exactly what the results are for our cars. Hoping to get 15% hp boost from premium is essentially confirmation bias in action. All anyone has determined is that if you feel like paying a fair amount more for gas to get a little bit more power and it makes you feel good to do so, then you should. If you enjoy saving money more than a couple hp and can't feel the difference then that's fine too as long as it's top tier. Although if anyone here is just leasing a Stinger for three years then you probably don't need to care about clean gas anyway, if you want to be a jerk for the next owner. That's something I'd definitely be concerned about buying a formerly leased BMW.

 

[Paul32]

Count me in the "best for my car" camp. I put UHP "Y" tires on my car because I want the pleasure of knowing that its (potential) performance is not in any way restricted by less capable tires. And HP is the same thinking. Enough car guys say that higher octane (top tier) gas is better for the engine over time. And now this resurrected thread resurrects the debate between "no real benefit to mileage or HP" and "10% to 15% gains". Does anybody really know? Is the argument between cars more than octanes? Unless somebody can show that the Stinger "doesn't care", I will continue to buy the gas that might benefit the engine, rather than the gas that might be inimical to the engine over time.

I don't care what the experts say, I ran two tests: 2 hundred miles, highway, 1 stop, cruise, 70mph, flat both directions, 89oct/93oct. Did not notice any significant difference, if anything felt better with the 89oct. The biggest difference was the price of gas. Still using 89 oct. I'll use my judgement and experience.