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Discussion Starter #1
Found this post on Reddit that talks about the benefit of higher octane in these high compression 2.4L and 2.0T engines.

The most interesting point was that on regular gas the 2.0T was actually slower than the base 2.4L even though the turbo engine has a substantial amount more horsepower.

Do any of you use 89 or higher? Do you see any benefits?

https://www.reddit.com/r/Hyundai/comments/jx1fd0
 

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Discussion Starter #3
where is this bozo getting his 0-60 times? not here:

every one i see is at least 2 sec faster. in cars, that is a LOT.
On that site, 2.4 vs 2.0T Santa Fe.
0-60 only a 0.3 second difference, so what he's saying may not be impossible.


Hyundai Logo

2018 Hyundai Santa Fe Sport 2.0T Ultimate AWD
0-60: 8.0
Quarter Mile: 16.2
More Info

Hyundai Logo

2018 Hyundai Santa Fe Sport
0-60: 8.3
Quarter Mile: 16.4
 

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I’ve used both high test and regular grade gas in my 2.4 and may have felt something different? Could just be a placebo effect. The fuel mileage did improve by a little, but it can also be because of a different driving habit. I haven’t seen any concrete evidence of it being a benefit but it would be nice to know
 

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I’ve alternated between ordinary 87 and 94 in my 2.0T and I didn’t see any difference. Nor did I feel any difference in acceleration, normal or flooring it, and no measurable difference in fuel economy either. Maybe in extremely hot temperatures and going up long inclines where the engine has to work harder and pinging is an issue I could see a need for premium, but I haven’t.

I do remember reading at some point, I don’t remember where and when, but I remember something along the lines that the 2.0T would produce around 10 lb/ft of extra torque using premium fuel vs ordinary. I don’t think 10 is noticeable, nor is it worth the extra price to fill up. If I floor it to pass, it gets up and goes plenty for the passing to be done quickly. Way more than the 2.4 I had in my ‘09 Sonata.
 

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I’ve alternated between ordinary 87 and 94 in my 2.0T and I didn’t see any difference. Nor did I feel any difference in acceleration, normal or flooring it, and no measurable difference in fuel economy either. Maybe in extremely hot temperatures and going up long inclines where the engine has to work harder and pinging is an issue I could see a need for premium, but I haven’t.

I do remember reading at some point, I don’t remember where and when, but I remember something along the lines that the 2.0T would produce around 10 lb/ft of extra torque using premium fuel vs ordinary. I don’t think 10 is noticeable, nor is it worth the extra price to fill up. If I floor it to pass, it gets up and goes plenty for the passing to be done quickly. Way more than the 2.4 I had in my ‘09 Sonata.
There are some important variables, that can alter knock occurance:
1. Intake air temperature
2. Coolant temperature
3. Engine RPM. The most knock-prone region is below 2000 rpm, because piston remains long near TDC.
4. Load. The more throttle valve is opened, the more pressure inside cylinders we have.

Now look at 2.0 t-gdi. Turbocharger gives us massive pressure increase below 2000rpm. That's why this motor behaves a lot like a diesel. BUT. To fully utilise this feature, only high octane fuel is suitable. Especially, if you use ECO mode.

And remember, the mission of an AT is to isolate you from an engine. To give you the same amount of acceleration, it can use lower gears and higher rpm with lower throttle opening (load).

Moreover, it takes time for ECU to adapt for the new octane number.

And yes, LSPI. Conventional knock is an LSPI trigger.
 

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In my opinion any turbo charged car that is designed to run on regular unleaded isn't a performance car.
Forced induction engine and low-octane fuel are direct opposites.
No matter, if the car, where turbo is installed, is performance oriented or conventional SUV.

To make the engine suitable for regular, there is only one effective way - low compression ratio. Turbocharging dramaticly increases effective CR.
For example, effective CR for forced induction motor with geometric CR 9:1 and 0.8 bar boost pressure is equivalent to 12:0 in similar NA engine.

2.0 T-GDI has geometric CR 10:1 and boost pressure 1.13 bar. Any other questions?
 

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Some people think that GDI is a magic technology, that eliminates knock at all. But, unfortunately, the cooling effect of fuel evaporation isn't as big, as it is advertised.
Let's take a look at the pair of the same engines, except for fuel injection system.
1. Theta 2 2.4 MPI that has traditional PFI.
It has CR 10:3.
2. Theta 2 2.4 GDI
It has CR 11:3.

Not a massive increase, isn't it?
An important note: high CR = high fuel efficincy, so engineers do their best to improve this parameter.
 

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My family have 3 Hyundai’s, 2013 Sonata Hybrid 80k, 2010 Santa Fe 112K, 2010 Tucson 65K. I like to run regular gas most of the time with Chevron Techron every other gas fill-up. When the weather changed dropping below 45f, I ran one tank of 94 pure petroleum (no ethanol) gas. It smooth out the idle and made the engines run smoother overall, better acceleration, better GPG 1-2, and even returning to reg. Gas the cars continue to run smoother.

Could it be the additive, detergents and fuel injector cleaners in the premium fuel with no ethanol? Ethanol has 1/2 the energy of pure petroleum-gas. Therefore 10% ethanol could cause 5% drop in fuel mileage. 1-2 mpg better fuel economy running premium (no ethanol) fuel certainly confirms it.
 

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My family have 3 Hyundai’s, 2013 Sonata Hybrid 80k, 2010 Santa Fe 112K, 2010 Tucson 65K. I like to run regular gas most of the time with Chevron Techron every other gas fill-up. When the weather changed dropping below 45f, I ran one tank of 94 pure petroleum (no ethanol) gas. It smooth out the idle and made the engines run smoother overall, better acceleration, better GPG 1-2, and even returning to reg. Gas the cars continue to run smoother.

Could it be the additive, detergents and fuel injector cleaners in the premium fuel with no ethanol? Ethanol has 1/2 the energy of pure petroleum-gas. Therefore 10% ethanol could cause 5% drop in fuel mileage. 1-2 mpg better fuel economy running premium (no ethanol) fuel certainly confirms it.
Don't know why I'm so cranky in the morning, but let's just say you're certainly not going to see 1-2 mpg increase when using premium fuel.
 

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Modern engines with knock sensor(s) can identity knock immediatly and change the timing immediately. The only thing that takes time is the fuel trims.
 

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Lately I will use two pumps. A half tank of 87 octane and a half-tank of 93 Premium. The trick is prior learning of how many gallons of fuel you will need that day.

If I am going to pay the in-between price for mid-grade 89 octane, then I may-as-well pay the exact same in-between price and pump my own custom-blend 90 octane, by mixing 87 with 93 octane.

Yes, my engines feel improvement with higher octane. But you can't measure the improvement on one or two consecutive tankfuls. Try measuring the performance & cleaning difference on 4-5 consecutive tankfuls.

If all you are interested in is to keep preventing lspi, then 87 octane is your cup of tea. Some of us want better gas mileage - better performance - less or no ethanol......etc. That's why we don't stick with 87 octane, even thou 87 provides us with a non-pinging / no lspi drive.

If I was not a 1st and last owner of my vehicles, I would cut financial corners and keep costs down. Then pass the lesser maintenance M.O. to the next owner, who's usually a stranger since a majority of Kias and Hyundais purchased new get traded-in.

Gonna rid the vehicle prematurely?.... buy 87
Gonna keep it until the junkyard gets it?..... then 89-93 octane
 

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Modern engines with knock sensor(s) can identity knock immediatly and change the timing immediately. The only thing that takes time is the fuel trims.
Don't forget, that you lose your efficiency and performance.
Moreover, permanent retarded timings could lead to exhaust valve's and turbocharger's overheat. Catalyctic converter won't thank you also.
 

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Gonna rid the vehicle prematurely?.... buy 87
Gonna keep it until the junkyard gets it?..... then 89-93 octane
Guess I can't ever get rid of these ridiculous statements.
Just another waste of money, and as asked in other threads,
please supply specifics to back up your claims.
I can supply specifics to only using 87 octane, can you supply
specifics that indicate a vehicle lasts longer using higher octane?

Don't forget, that you lose your efficiency and performance.
Moreover, permanent retarded timings could lead to exhaust valve's and turbocharger's overheat. Catalyctic converter won't thank you also.
If and when a KS ever intervenes, how far back to you think the timing is retarded? Permanent retarded timing????? It's not like the timing is retarded every mile you drive.
 

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Guess I can't ever get rid of these ridiculous statements.
Just another waste of money, and as asked in other threads,
please supply specifics to back up your claims.
I can supply specifics to only using 87 octane, can you supply
specifics that indicate a vehicle lasts longer using higher octane?



If and when a KS ever intervenes, how far back to you think the timing is retarded? Permanent retarded timing????? It's not like the timing is retarded every mile you drive.
Every time you accelerate when your engine is below 2000 rpm, your timings are retarded on 87 AKI. You can clearly feel it. AT usually shifts to lower gear to save the engine.
 

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When I know the weather will be 90+F I add a 1/2 tank of premium to 1/2 tank of my normal regular.
Runs a little peppier, especially in stop-and-go with AC cranking, but no change in MPG.
Also did this with my previous 2006 Toyota, which also had a knock sensor.
 

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Don't forget, that you lose your efficiency and performance.
Moreover, permanent retarded timings could lead to exhaust valve's and turbocharger's overheat. Catalyctic converter won't thank you also.
lThere is nothing permante about the timing changes. They are based on static tables and the knock sensors add and stubtract from those tables if knock is heard. It's one and done how ever many times it knocks as far as the changes. It does slowly ramp back up to the full table value after a few rpms.
 

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Discussion Starter #19
Lately I will use two pumps. A half tank of 87 octane and a half-tank of 93 Premium. The trick is prior learning of how many gallons of fuel you will need that day.

If I am going to pay the in-between price for mid-grade 89 octane, then I may-as-well pay the exact same in-between price and pump my own custom-blend 90 octane, by mixing 87 with 93 octane.

Yes, my engines feel improvement with higher octane. But you can't measure the improvement on one or two consecutive tankfuls. Try measuring the performance & cleaning difference on 4-5 consecutive tankfuls.

If all you are interested in is to keep preventing lspi, then 87 octane is your cup of tea. Some of us want better gas mileage - better performance - less or no ethanol......etc. That's why we don't stick with 87 octane, even thou 87 provides us with a non-pinging / no lspi drive.

If I was not a 1st and last owner of my vehicles, I would cut financial corners and keep costs down. Then pass the lesser maintenance M.O. to the next owner, who's usually a stranger since a majority of Kias and Hyundais purchased new get traded-in.

Gonna rid the vehicle prematurely?.... buy 87
Gonna keep it until the junkyard gets it?..... then 89-93 octane
When I know the weather will be 90+F I add a 1/2 tank of premium to 1/2 tank of my normal regular.
Runs a little peppier, especially in stop-and-go with AC cranking, but no change in MPG.
Also did this with my previous 2006 Toyota, which also had a knock sensor.
I like the mix, I do around 25-33% 94 octane and the rest regular 87.
This leads to an end number of 89 or so.
A difference of only about $5 CAD. Much cheaper than filling only midgrade 89 for the full tank.
 

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I been running a few tanks of Shells V-Power lately to clean out the fuel system being winter is here just for Mantance purposes. i will say though it does seem to start a little Quicker & run smoother latley on Shells V-Power engine does like the Fuel. also with V-Power theres no ethanol in it.
 
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