What OBDII code is set when your check engine light comes on?

I've run two tanks of 93 octane and did not have a CEL - I went back to 89 octane because I didn't feel any seat-of-the-pants difference.

 

Go to a different gas station? Racechip not a real tuner. You should never get a engine light running 93 on this car.

 

You might if the fuel is achieving 93 octane by running 25% ethanol or something, but that would be unusual, because I think they'd have to label the pump for that. Pretty much every car sold in North America can run E10 (10% ethanol) fuel, but beyond that concentration, ethanol would screw with the O2 sensor readings (and potentially damage seals in the fuel system), so it's a pretty big deal if the fuel has more than 10% ethanol without it being labelled on the pump.

Also, I'm pretty sure my Canadian 2021 Forte manual (there is no separate manual for the GT) states 87 octane or better fuel. It doesn't provide a maximum octane rating, and I have never seen that in any car ever. It does specify the maximum amount of ethanol allowed and that fuels containing methanol should never be used. There's also possibly no use in running 93 octane fuel. Has anybody been able to determine if the engine with a stock tune actually provides better performance above 87 octane? Most turbo engine do, but they always tell you in some way. Something like "87 octane acceptable, 91+ octane recommended" (like my Dodge Dart 1.4T did) or they actually provide the reduced horsepower rating with 87 octane (like the Ford Focus ST did). Kia just says "87 octane or better" on an engine they are advertising as 201hp, so they could be in hot water if it can't make 201hp on 87 octane fuel.

 

Mine is stock, and I've run 93 almost exclusively since I bought it 4K miles ago. It's not the gas.

 

I have a 2021 Forte 6MT with the naturally aspirated 2.0. Reading the specs on the engine, it has 12.5:1 compression ratio. Typically, once you hit 11:1 you require 91 octane if your engine does not have variable timing. This in and of itself suggests potential for effective utilization of higher octanes. In another thread I noted an odd acceleration curve, and after using 91, I can say that they has definitely smoothed out, although I can't say it has had actual performance gains. My next step is to boost the octane even further with additives, and then abruptly go back to 87 to see how much of a difference I feel.

Theoretically, if the engine has higher compression and variable timing and fueling, it should extract more kinetic energy with higher octane.

 

I have a 2021 Forte 6MT with the naturally aspirated 2.0. Reading the specs on the engine, it has 12.5:1 compression ratio. Typically, once you hit 11:1 you require 91 octane if your engine does not have variable timing.

Sorry but that is not correct. Static compression does not take into account valve duration and timing. You will not see any gains by using higher than 87 on your stock n/a motor.

 

I have a 2017 Forte S and have always run on 93. Never had a Check Engine light.

 

You’re wasting money.

 

The car makes more power with better fuel even on the stock tune (GT). Enough to feel? No, Enough to make a difference? Sure if you fix all the other issues (the launch, shifting, DA, track conditions).

My car has made 195 whp uncorrected Map 0 (pass-through) on 91 octane. It's made 201 whp with 20% Ethanol.

I am really tired of this debate especially coming from the same guy who's car is stock, s-slow and is a typical Hyundai/Kia owner IE they don't really know it's strictly guessing.

 

I am really tired of this debate especially coming from the same guy who's car is stock, s-slow and is a typical Hyundai/Kia owner IE they don't really know it's strictly guessing.

Higher octane in on a stock N/A forte is doing nothing draining your wallet.You are getting zero performance increase. Period.

 

Take it to the dealer, you shouldn't get a code at all.

Racechip? No

 

Do your research:

13:1 Compression and 40 mpg on 87 Octane fuel? Introducing Mazda’s Skyactiv Technology - Page 2 of 7 - MotoIQ

, One of the Skyactiv G engine’s design goals was weight reduction, particularly reciprocating weight. The old Mazda 2 liter engine’s crankshaft was designed to take the load of turbocharging…

motoiq.com

Mythbusting Octane, The Truth About Gasoline

The next time someone tries to pass these gasoline-related myths off on you, you can try explaining to them how octane ratings really work.

www.nicoclub.com

 

The Forum Warrior is back in a thread he doesn't belong in again, doesn't even own the car, and does more internet search copy pasting. Most ppl have alrdy told you to leave threads and mods deleted ur nonsense and posts. Why bother patrolling here. Go find a different hobby. Another derailed topic for u to weasel ur way in.
This person who made this thread just needs to go the dealership and get the car looked at for a check engine light on when using pumped gas or go to a different station and see if its that's the issue. If mixing E blend to achieve a higher lvl he might want refigure his mix numbers. Ill be getting a mod in here to keep from back and forth nonsense that i see is happening.

 

Holy Cow! I didn't realize 93 octane would cause this kind of "misfire"!

 

Holy Cow! I didn't realize 93 octane would cause this kind of "misfire"!

Haha, I see what you did.

Just put what grade fuel Kia recommends. Will you get better performance with 93 octane? Probably but will it be noticeable, probably not.

Sent from my SM-T380 using Tapatalk

 

 

Alright well, that was fun. Thread has been cleaned up, let's get back on topic, please.

 

Fun? Not really. Maybe just get rid of the problem and then never have to deal with it again. Sending nasty PMs to someone doesn't sound like fun to me.

 

Oh you got one of those too?

I don't understand, he's not arguing from a position of strength.

I have gained 57 whp from stock with one mod. To get more than that from a traditional V8 would take nitrous oxide. Nothing wrong with that as it makes similar gains with the 1.6T -



The problem comes from trying to move nearly 4000 lbs of metal. When the Forte comes in around 3000 lbs.

Remember: 10 hp = 100 lbs = 1 tenth = 1 mph (1/4 mile)

So he would have to make more than 250 hp with his current SBC build and additional 100 hp on top of that. What he doesn't know is that forced induction, especially turbocharging makes nitrous more efficient.

First it's doubtful his Nova even makes that with the engines mild spec sheet when considering the accessories, automatic transmission, driveshaft, rear end housing and axles.

This is all off topic and I didn't drag it there. The original post was from a GT owner, it's the 2.0L owner that derailed it making it off topic, not understanding that you'll see zero or any benefit off anything higher than 87 octane. The GT with the turbocharged engine is a different kettle of fish. In your manual (if you own a GT) it say "87 octane or HIGHER". Knowing how OE's get their rating with performance vehicles they used the best fuel available, since the majority of the country has access to 93 octane or RON 98 overseas.

The Pro'Ceed GT makes 204 hp overseas.

Even though the new 2021 Elantra N-Line has the new Smart Stream engine it still rated at 201 hp

As I've said before this type of performance hasn't been available to the Hyundai/Kia community until recently so the majority of it's ownership base is inexperienced. That's not a knock but it allows others to play on your ignorance, just be aware of that.

 

Well, hopefully @d2freak82 was ran away and comes back to share what happened if he changed octane or gas stations. Curious on why he got the CEL.

 

Sorry for the delay I've been at the lake all weekend, quite a thread for my question lol.

So I did take this to the dealer when the CEL was on, they had it for 3-4 days, couldn't figure out what was wrong with it. They kept saying bad fuel, too much alcohol. They changed the plugs, put 87 octane in and it shut off. After a few fill-ups with 93 octane it came on again, and the next fill I used 87 octane and it shut off.
The reason I'm putting 93 octane in - it's cheaper here than 87, and if my car performs the same or even has a hint of better performance I'm happy to use the cheaper. My wife has an infinti q50 3.0t - we fill it with the same fuel have for a couple years, no issues. My mother has a Kia Soul or whatever those hamster mobiles are, she fills with it too - no issues (she doesn't have the turbo though, I believe the 2.0).
Not sure what to do - I will try another station with higher octane fuel and see what happens

 

Sorry for the delay I've been at the lake all weekend, quite a thread for my question lol.

So I did take this to the dealer when the CEL was on, they had it for 3-4 days, couldn't figure out what was wrong with it. They kept saying bad fuel, too much alcohol. They changed the plugs, put 87 octane in and it shut off. After a few fill-ups with 93 octane it came on again, and the next fill I used 87 octane and it shut off.
The reason I'm putting 93 octane in - it's cheaper here than 87, and if my car performs the same or even has a hint of better performance I'm happy to use the cheaper. My wife has an infinti q50 3.0t - we fill it with the same fuel have for a couple years, no issues. My mother has a Kia Soul or whatever those hamster mobiles are, she fills with it too - no issues (she doesn't have the turbo though, I believe the 2.0).
Not sure what to do - I will try another station with higher octane fuel and see what happens

Now I think it's the gas you are purchasing. Doesn't make sense for the CEL to set - still would like to know what code they are reading!

 

I want to know where you live that 93 is cheap than 87!

 

I went to the fueling station a few minutes ago - the 93 octane has 30% ethanol

 

Well there's yer problem, glad you figured it out! E10 or less from now on.

 

If it's true that your local 93 octane is up to 30% Ethanol, then yes you will benefit from a JB4. The others will require additional apps like Torque to ensure nothing strange is happening and if you don't know how to read logs, then you are better off with the JB4.

Because the base Map 1 tune (no OBD-II port connection) is +4 over stock and that request for more boost makes more power.

Map 1 on my car made 211 whp on Map 1 on 91 Octane and 222 whp on E40 (40% Ethanol mixed with 91 octane @10%)

Stock is 190-195 whp (DCT vs Manual Transmission)

*My Enkei Wheels look like they are worth 3-4 whp (40+ lbs drop in unsprung weight). With stock wheels 207-208 whp on 91 and 217-218 whp on E40

If you aren't interested in that (you did mention a Racechip) then run 89 or if available 92 ethanol free fuel. I lost power higher than E20 on the stock tune.

Nobody has done more dyno testing than me, period.

 

Stock is 190-195 whp (DCT vs Manual Transmission)

This surprises me, since it's only rated at 201 brake horsepower. I'm not questioning it, since I assume it's the result of your extensive dyno testing, I'm just surprised.

 

What is surprising? Unless you know exactly how much power the manual or DCT takes to drive transmissions it really shouldn't surprise.

The car made 201 whp with E20 (20% Ethanol), stock tune.

It's made 210, 208, 208 and 211, three different dynos, two Dynojet and one Dynapak. Map 1, 91 octane.

198, 195 & 195 stock tune, 91 octane. It makes less power with Sport mode off, about 4-5hp and it's repeatable.

The car is capable of low 14's to high 13's in the 1/4 mile on premium fuel. The problem is the person behind the wheel and the lack of traction.

Any 60ft above 2.0 won't cut it.

The car is not slow.

 

The car is not slow.

This is very true, it's not a slow car, especially for its price point, and I absolutely love that about it! I was curious how it fared performance-wise compared to other cars and found that numbers-wise, it's comparable to the most recent Civic SI. It's not priced like a Civic SI, though, and it has a DCT option to make it more accessible (that's actually the only option in Canada, there's no manual GT here).

It's surprising because it means that either the transmission only has ~3-5% parasitic power loss (not possible), or Kia rated it at 201hp using 87 octane fuel and it actually creates more power using higher octane fuel on the factory tune, which seems likely, considering your testing results. This is just not how automakers generally go about making hp claims on turbocharged engines. Usually they advertise the hp number it makes on premium fuel, and then allow you to run it with regular fuel with a decrease in performance.

I do appreciate all the testing you done and the sharing of the knowledge you've gained. It's people like you that make these forums more than a place for "how do I fix X?" stuff.

 

Lots of OE's don't fully tell the truth about their car's output, likely for insurance reasons or even EPA MPG requirements, who knows.

The Neon SRT-4 was heavily underrated. The Mk7 Golf GTI was not really 225 hp, it's dyno'ed way higher than that on premium fuel.

I am not surprised one bit what I found on the dyno. As soon as I was able to take it to an open 1/4 mile, it took two passes to run 13.75@101.9 (JB4 only, Map 3). About two weeks after that same track this time with the WMI on, it ran 13.77@103.47 in 90 degree heat but track is only 15 ft above sea level so DA stays under 1,000 ft.

I took it to Arizona for high temp, high DA testing, ran a bunch of low 14's and one 13.96@98 mph. The 60 ft times aren't great but I am hard at work on fixing that and about 90% done. I also got in some Whiteline anti-lift bushings not sure I'll need those we'll see, I hope to get rid of these rear engine mount inserts, I just don't need the NVH but it did help with wheel hop.

Sport Mode, TCS off, burnout.

2.0x mostly, a few 2.1x

Much better results coming.

 

I work for Kia, what's the DTC? Sounds like bullshit to me. I run 92 in mine without issue. It's not a octane rating problem. Alcohol problem could be possible but your car would run terribly as a most likely scenario. I've seen some bad gas but it is quite literally one of the least common problems. Buy ethanol free if you like, won't hurt. These cars do run fine with 10% ethanol and in order to create a drive ability issue. You'll need at minimum a 15% ethanol mix to create huge problems.

I've seen em run fine at 11, 12, 13 % ethanol. 14-20% is a no go and they run like crazy. I seen a guy put 14,000 dollars worth of parts in a car, all for bad gas. However, as stated earlier. Bad gas is very rare. I wanna know what your DTC is.

 

The part I hate is that when you fuel up the message on the gas pump says: "May contain up to 10% ethanol". I take that to mean it may be 5%...6%...10%...12%...13%...15%! All depends on how much ethanol the delivery truck filler felt like putting in it...

 

Gas is really all the same. They pull it out the same tanks. Arco, 76, Shell etc... its all the same gas with a slightly different additive. When people say, I got bad gas and Arco sucks. In fact, Arco is one of the best fuels out there and I have routinely checked Arco fuel for alcohol and volatility and consistently find Arco alcohol content hovers between 7-9%. There is no such thing as bad gas.

You just found a bad tank or a bad station.

 

The ACTUAL ethanol content may be the reason why sometimes it appears that you get really good gas mileage after a fill up and then the next time you fill up it seems to be worse mileage...

 

2020 Forte GT2. Never have put anything less than 93 in my car and never had issues. That gas station is probably one you shouldn't visit. 30% ethenol... That explains that.

 

Octane requires higher compression to burn.

The 1.6 has a 10. 5 to 1 compression ratio and doesn't require 93 octane. Ocane is fuels resistance to burning. Only higher compression engines need the higher octane to prevent pre detonation. I run 87 all the time and no issues. Any mid grade between 87 and 93 is ok to run but your wallet is the only one who cares. Anyway run regular and keep it to the floor.

 

Octane requires higher compression to burn.

The 1.6 has a 10. 5 to 1 compression ratio and doesn't require 93 octane. Ocane is fuels resistance to burning. Only higher compression engines need the higher octane to prevent pre detonation. I run 87 all the time and no issues. Any mid grade between 87 and 93 is ok to run but your wallet is the only one who cares. Anyway run regular and keep it to the floor.

The octane rating is a measure of a fuel's resistance to knock under pressure. The "compression ratio" of an engine is a static figure that represents the difference in cylinder volume between bottom dead center and top dead center. It doesn't necessarily represent anything about the actual pressure in the cylinder. The 1.6L engine might have a compression ratio of "only" 10.5:1 (I believe it's actually 10:1), but it's also turbocharged, and it's really disingenuous to ignore that. Yes, a Forte GT with the 1.6T engine will run just fine on 87 octane fuel, but it will make even more power on 89, 91, or 93 octane fuel. Modern engines use advanced variable valve timing, fuel injection, and electronic ignitions to allow this, but what is typically happening with 87 octane fuel in a turbocharged engine is that you are taking a more powerful engine and de-tuning it so that it will still run properly without detonating. Many automakers advertise the power generated with 91 octane fuel (Ford with EcoBoost engines, for example, where they actually note the reduced hp/torque figures with lower octane fuel in the owner's manual), but Kia has apparently taken the route of advertising the 87 octane power rating, which is pretty impressive at 201hp (just over 125hp per liter). Since 87 octane or higher fuel is what they specify, they have seemingly made the choice of deliberately under-rating the performance of their 1.6T engine for whatever reason. In any case, it makes the Kia Forte GT an exceptionally good value for its price point, and a very fun car indeed.

 

Y'all can pretend that these 1.6T engines are lazy lumps of cast iron, but this is no Corolla. Kia have tuned this tiny little 1.6L turbo engine to produce a lot of power. The turbo raises intake pressure in the cylinder by more than 15PSI under load and adds a lot of heat. It only takes a simple google search "Kia / Hyundai pre-detonation issues" to see that they have already had to update software in older cars because these tiny 4-cyl engines with all of this tech and high compression destroy themselves trying to meet EPA regulations. Personally, I have learned too much about what causes Low Speed Pre Ignition and what it can do to your engine to feel comfortable putting 87 in a forced induction engine, or even a high compression NA engine.

For me, an extra ~$5 per fill up is pretty cheap peace of mind.

 

Y'all can pretend that these 1.6T engines are lazy lumps of cast iron, but this is no Corolla. Kia have tuned this tiny little 1.6L turbo engine to produce a lot of power. The turbo raises intake pressure in the cylinder by more than 15PSI under load and adds a lot of heat. It only takes a simple google search "Kia / Hyundai pre-detonation issues" to see that they have already had to update software in older cars because these tiny 4-cyl engines with all of this tech and high compression destroy themselves trying to meet EPA regulations. Personally, I have learned too much about what causes Low Speed Pre Ignition and what it can do to your engine to feel comfortable putting 87 in a forced induction engine, or even a high compression NA engine.

For me, an extra ~$5 per fill up is pretty cheap peace of mind.

If you watch all the videos in this thread and listen to those that write about "compression ratios" you'll notice that they all talk about low compression ratios in turbo engines. Kia's 1.6T has a 10.5:1 compression ratio - THAT is not low compression! You can bet that during high load conditions the engine is reducing power by retarding the timing to prevent pre-ignition because of 87 octane gas.

 

IMO 87 is fine! It is what Kia recommends...for normal driving. However, for people who drive their cars and only use two throttle positions - idle and WOT - a higher octane would be better.

 

lol maybe if youre in constant "abuse" mode , sure