2019 Kia Sportage. SX with AWD. 2.0L Direct Injected Turbocharged & Intercooled Gas.
I am pleased you finally agreed that an engine can reach higher levels of HP output on Higher Octane Fuel.I don't know how many ways I can say this, BUT THIS IS JUST NOT TRUE FOR OUR CAR. This subject has been researched by people far more knowledgeable than you or I -- and I read much of the research. It is confusing because there are many cars where this is true. It all depends on the design of the engine and the way the ECM has been programmed. What happens is that when you put in premium, the car doesn't know that fact. So the ECM constantly tries to improve performance by pushing the limits. If you get a high performance vehicle with a large engine, then there will be a difference in the majority of cases. But in the tests I've seen for turbocharged small 4 cylinder vehicles, there has been no added performance WHEN THE MANUFACTURER SAYS TO USE 87 GAS. To make the generalization that premium will ALWAYS give you higher power FOR OUR CAR is just wrong. Technically, you're not going to hurt your car with premium gas either. You are just wasting your money for no added benefit.
Your statement that 87 gas won't hurt anything is important. Those who use premium gas so their engines will last longer are clearly wrong and you and I would agree on that. So, for argument's sake, let's say you do have a power increase with premium fuel. The first question is how much of an increase will it be. In the testing I've seen for other cars WHERE THE MANUAL SAYS THAT PREMIUM WILL GIVE YOU ADDED HP, the increase is in the range of 5%, i.e., 20hp for a 400hp engine. In these engines, when you use 87 gas, your car is detuned. (It is NOT detuned for our car). So let's say that you can achieve half that result, or 2.5% or about 6hp on the 2.0 turbo. Because of engine dynamics, that 6 hp will only be fully useful when the engine is pushed -- not when you are driving normally. So, you MIGHT get it when passing a car or accelerating on the freeway. The question for the owner then comes down to how much extra money do you want to spend for a slight performance increase useful only a small part of driving time.
I've seen a few tests where using premium actually decreases power. I have trouble believing this, but they were done by competent organizations and mostly in Hondas. It seems you can program the ECM to provide more economy with higher octane gas and this actually decreases hp. This strategy would make sense if you are selling economy vehicles. I don't know if Kia does this and until our car is tested, there's no way of getting this answer.
Much of what happens when we buy a car, given that it is one of the most expensive purchases by most of us, is that we are human and it affects our psychology. We want to treat it well as if it was a member of the family. So we clean it often, we buy "jewelry" for it, and we "feed" it the very best. Is this really necessary? No, but it makes us feel better. I've changed the Kia logos and put a trim ring on my steering wheel. Does this make the car perform better? Again, we both agree that premium will not make your engine last longer and your car just doesn't need it.
I guess I just don't know how you can make your generalizations with the abundance of tests by competent organizations saying there is NO benefit for using premium fuel in cars designed to use regular. They clearly don't agree with you. Don't get me wrong, your argument does make "common sense" based on generalizations. And, it was exactly what I believed over a decade ago when I retired and had the time to research issues like this. The research changed my mind from the simple "common sense" argument, to a more sophisticated understanding.
In the end, what's important here, is that there is no benefit to the HEALTH of your car in using premium fuel. And we both agree on that. There might be a very slight power increase if your generalizations are true for our specific car, but is that worth all of the extra money you pay for it? For me, after doing all of my research, tuning track cars, and actually visiting engine manufacturing facilities and talking with the engineers, I just don't buy the generalization FOR OUR CAR. So, are you willing to spend all of that money for the life your compact, economy SUV just on the speculation that there might be a power increase that's only usable a small part of your driving time????? Hmmmm.... The answer for me is clearly no....
Its actually higher than 6 HP. More like 10 to 15, as measured on a chassis dyno. And, that was the basis of this thread that the OP raised the question. Max HP. Have a blessed day!