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I would like to share some of my input that I've been able to "log" with 2 simple devices: an OBDII scanner along w/ car scanner app for iphone, and a dragy perf. meter...
Coming from a car that RECOMMENDED 93 octane for better performance, and doing some "research" on the 1.6t engine prior to buying the Forte, I decided to continue on w/ fueling up w/ 93...

Did a few runs/pulls 0-60s, 45-65, 20-60, 80-100 mph plus a few others, 1/4 mi, 1/8 mile...cool. Quick car.

After 2 1/2 months of fueling up w/ 93, I decided to try out 89 octane...

There are NO differences between 89 and 93....at all. None that dragy can show. Taking into account variations in temperatures and DA, of course. I am at sea level.

Back when I was running 93 octane, the car scanner app "logged" 226.76 hp @ 55F, on 89 octane the app logged 221.65 hp @73-77F... Granted, I do not know the accuracy of the OBDII scanner in proving engine HP, seem pretty accurate for other values I occasionally track, and 220-227 at engine would equal ~182-192 at the wheel...

I don't know if there are any differences between the 2020 and 2021 Fortes, (I don't think so), but at least that's what my '21 is showing me.
Wow! Imagine than. Higher octane doesn’t create higher horsepower. I said that months ago but the “experts” here said I was crazy. Better be careful, you might get banned for telling the truth. Thanks for the data.
 

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Wow! Imagine than. Higher octane doesn’t create higher horsepower. I said that months ago but the “experts” here said I was crazy. Better be careful, you might bet banned for telling the truth. Thanks for the data.
Ok, I see you have a strong opinion on this. Would you care to explain what the purpose of higher octane fuel is? Perhaps you can add some kind of value to this forum? Or are you just here to be passive aggressive?

For anyone interested in learning something
Octane is a measure of knock resistance. Knock occurs when the air/fuel mix explodes before the spark plug ignites it. Lower octane fuel will randomly combust at lower temperatures and pressures than higher octane fuel. This makes higher octane fuel a better choice for high compression engines and forced induction engines, as there are higher pressures in the cylinders.

Modern engines (Like the 1.6L Turbo in the GT) can change the timing for when the intake and exhaust valves open and close, the length of time the valves are open for, the spark plug timing, the boost pressure, and the air/fuel ratio using computers. These variables are changed based on sensor data and driver inputs. If the driver demands power, the computers will try to get the most power before it starts sensing knock, then it rides that fine line until full power is no longer requested. Then the computers go back to balancing fuel economy and emissions when cruising.
 

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Except he's not passive aggressive lol.

(I've been honored the last go-around with getting a PM stating "Piss off asshole and mind your own business.")
 

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Ok, I see you have a strong opinion on this. Would you care to explain what the purpose of higher octane fuel is? Perhaps you can add some kind of value to this forum? Or are you just here to be passive aggressive?

For anyone interested in learning something
Octane is a measure of knock resistance. Knock occurs when the air/fuel mix explodes before the spark plug ignites it. Lower octane fuel will randomly combust at lower temperatures and pressures than higher octane fuel. This makes higher octane fuel a better choice for high compression engines and forced induction engines, as there are higher pressures in the cylinders.

Modern engines (Like the 1.6L Turbo in the GT) can change the timing for when the intake and exhaust valves open and close, the length of time the valves are open for, the spark plug timing, the boost pressure, and the air/fuel ratio using computers. These variables are changed based on sensor data and driver inputs. If the driver demands power, the computers will try to get the most power before it starts sensing knock, then it rides that fine line until full power is no longer requested. Then the computers go back to balancing fuel economy and emissions when cruising.
Higher octane doesn't create power. Octane is a resistance to pre-ignition. What creates more power on higher octane fuel is the tuning in the computer that allows for more aggressive timing that would cause pinging on lower octane fuel. So it's not the fuel that makes more power, it's the tuning. The fuel just allows that tuning to be used.

Now, the factory tuning does not take advantage of the higher octane so that's why it doesn't make more power. That's what I've said all along. Cars designed to run on 87 will not make more power on higher octane. Now, if you change the computer tune that's a different story. But, on a FACTORY TUNE car that has a STOCK, unmodified engine, you are getting zero benefit from higher octane fuels.
 
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Higher octane doesn't create power. Octane is a resistance to pre-ignition. What creates more power on higher octane fuel is the tuning in the computer that allows for more aggressive timing that would cause pinging on lower octane fuel. So it's not the fuel that makes more power, it's the tuning. The fuel just allows that tuning to be used.

Now, the factory tuning does not take advantage of the higher octane so that's why it doesn't make more power. That's what I've said all along. Cars designed to run on 87 will not make more power on higher octane. Now, if you change the computer tune that's a different story. But, on a FACTORY TUNE car that has a STOCK, unmodified engine, you are getting zero benefit from higher octane fuels.
Yes exactly, that is the real question here. I do know that other manufacturers have multiple fuel maps for different fuel types. Ford advertises HP ratings for both 87 and 91+ octane fuels. The real question here.

Does Kia only have one fuel map for 87 that makes 201HP? And will not allow more power to be created even with higher octane?
Or did Kia do like some other manufacturers have done: List 201HP on 91 Octane, then allow the engine to de-tune itself down so that it can run 87 octane?

The only thing that makes me think there is a fuel map for higher octane fuel is that it states under recommended fuel "87 Octane or higher" rather than just saying "87 Octane Minimum" like most other vehicles that are not tuned for 91+ I honestly have no idea. This is the type of thrilling conversation I was looking for though, sorry if my response came off a bit snippy. I am just tired of digital spaces where people just yell at each other and don't discuss anything with substance.

Tableware Facial expression Picture frame Gesture Tie
 

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The Forte GT is tuned for 87 Octane to produce the stated 201HP.

It is not like the EcoBoosts and others that needed the 91+ to produce the rated HP.
 

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Yes exactly, that is the real question here. I do know that other manufacturers have multiple fuel maps for different fuel types. Ford advertises HP ratings for both 87 and 91+ octane fuels. The real question here.
Fortes are not Fords.

Does Kia only have one fuel map for 87 that makes 201HP? And will not allow more power to be created even with higher octane?
Or did Kia do like some other manufacturers have done: List 201HP on 91 Octane, then allow the engine to de-tune itself down so that it can run 87 octane?
Fortes are designed to only run on 87. There is no secondary map for higher octane fuels like SOME other cars. Yes, there are cars out there that have multiple tunes that will decrease power when running on 87 octane fuel but Fortes are not one of those cars.

The only thing that makes me think there is a fuel map for higher octane fuel is that it states under recommended fuel "87 Octane or higher" rather than just saying "87 Octane Minimum" like most other vehicles that are not tuned for 91+ I honestly have no idea. This is the type of thrilling conversation I was looking for though, sorry if my response came off a bit snippy. I am just tired of digital spaces where people just yell at each other and don't discuss anything with substance.
They say 87 or higher because less than 87 will cause problems but higher won't. That doesn't mean higher gets you more power, it just means 87 is the minimum. Higher octane won't gain you any performance but it also won't hurt your engine like under 87 octane will.
 
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Yes, you are right. I'm aggressive when idiots like yourselves ask a for the lack of a better term "stupid question" and Master Mechanics like myself and Nova repeatedly explain knowledgeably without having to look it up online from a post written by another keyboard mechanic, then you want to get into a back and forth pissing contest. Would you argue with the doctor who answered your question because you read something different somewhere online? No, you wouldn't but you guys sure as hell want to do it here. I wish all of you the best with the mess that you have or will make of your cars. I fix and deal with enough ignorant customers all damn day long.
 

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Alright alright, @NovaResource & @BlueStang I will have to try it for myself. I have driven 6,000 miles so far using 93. I have an ultra-gauge I can use to monitor timing advance to see if it beings retarding the timing more and more. I'm curious now.

Yes, you are right. I'm aggressive when idiots like yourselves ask a for the lack of a better term "stupid question" and Master Mechanics like myself and Nova repeatedly explain knowledgeably without having to look it up online from a post written by another keyboard mechanic, then you want to get into a back and forth pissing contest. Would you argue with the doctor who answered your question because you read something different somewhere online? No, you wouldn't but you guys sure as hell want to do it here. I wish all of you the best with the mess that you have or will make of your cars. I fix and deal with enough ignorant customers all damn day long.
Well you're just being aggressive-aggressive.
 
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Tee EcoBoost in Ford's that require 93 Octane to produce rated HP do not have more than 1 map/tune.
As a former '16 EB mustang owner, Ford RECOMMENDS 93 for improved performance - it's in the manual. You can run 87 youll just be slow....
93 vs 87 on THAT car makes a HUGE difference. HUGE. lol 93 yields 0-60s in the 5.4-5.6 sec, on 87 good luck getting sub 6 secs (for the '15-1'17 models before the 10 speed), the 10 speed on 87 might do 5.85 sec..on a good run.
Mazda with their 2.5t's do the same thing, though Mazda is more transparent about it unlike Ford. You can fuel up w/ 87 , youll just be slower...

The Forte is not one of those cars.
 

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Kia Owners Manual:

83079


Use the fuel with the octane YOU want to. You're paying for it - not them. You don't need approval from moral superiors on the internet. BTW That is NORMAL OPERATION -- Kia is not about to add a statement for "performance operation" - that could turn out to be a warranty nightmare in a court of law...LOL!
 

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“Or Higher” just mean you are required to have a minimum of 87. Below that causes damage but above that does not give more power. It just wastes money.
 

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“Or Higher” just mean you are required to have a minimum of 87. Below that causes damage but above that does not give more power. It just wastes money.
That's my point! It's their money and their car. If they want to burn 89 or 91 octane fuel, and feel better for it, more "power" to them.

I do not understand why people who don't own the car or buy the fuel feel they have a say in what the owner does!

If it was ALL ABOUT the money then why not berate them for buying a more expensive model when they could have saved even more money by buying an FE model?
 

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All I set myself out to do was to find out if there was any differences in performance with higher octane. My testing proved there is NO improvements to be had with this specific car. I made a few comments that if you (owner) wishes to fuel up w/ 93 that's okay that I am not trying to steer you away from it. Like I posted in another comment, just know that it is no getting you better performance. That is all I wanted to contribute to this community. I don't understand why its such a heated debate...specially for the Forte, it is a great little car, and I actually like the fact that it can do mid-low 6 seconds w/ low octane whereas other cars NEED 93 to be FAST (EB mustang, Mazda, among others, of course, GTI/GLI's need 91, etc), but it is not set out to be a PERFORMANCE car.

By utilizing an OBDII, I've seen a peaks in boost of 17-18 psi with both octanes (that's impressive), avg of 16.5-17 psi.

If 93 makes anyone feel better, go ahead and fuel up w/ it. I am nobody to tell you what to do with your coin.
 

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What about air temps? Does the higher octane help with pre-detonation because the higher air temp, say like 90 or 100F (and higher lately lol)?
 

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That's my point! It's their money and their car. If they want to burn 89 or 91 octane fuel, and feel better for it, more "power" to them.

I do not understand why people who don't own the car or buy the fuel feel they have a say in what the owner does!

If it was ALL ABOUT the money then why not berate them for buying a more expensive model when they could have saved even more money by buying an FE model?
I’m not trying to change your mind. I’m just correcting misinformation being given out so that when people come here days, weeks, months, or years from now will see correct information, not false statements. If you or anyone else wants to throw away their money for zero gain, go ahead. But I’m letting the future owners/readers know the facts.
 

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What about air temps? Does the higher octane help with pre-detonation because the higher air temp, say like 90 or 100F (and higher lately lol)?
Yes, and when you're going up a steep hill, and when you give it gas at a low speed with the tranny in a high gear, and...

Kia says 87 octane or higher for normal operation. I'll bet dragstrip operation doesn't fit under "normal operation"...
 

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All I set myself out to do was to find out if there was any differences in performance with higher octane. My testing proved there is NO improvements to be had with this specific car. I made a few comments that if you (owner) wishes to fuel up w/ 93 that's okay that I am not trying to steer you away from it. Like I posted in another comment, just know that it is no getting you better performance. That is all I wanted to contribute to this community. I don't understand why its such a heated debate...
Because some people think they know everything and if you say anything that goes against their collective intelligence, they attack you for it. And then ban you. Actual intelligence used to be admired here. Back when this forum was active and vibrant and good.
 

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Because some people think they know everything and if you say anything that goes against their collective intelligence, they attack you for it. And then ban you. Actual intelligence used to be admired here. Back when this forum was active and vibrant and good.
Why is a different point of view an attack?

You made your point - they're probably wasting money...but then you come back and say "some people think they know everything" and "you're an idiot for using 91 octane fuel".

Everyone has an opinion...you can accept that or you can argue about it all day.
 
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