Lower octane in turbo engine

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poiuy223

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I've been reading the Hyundai forums and many are posting that the 2.0t engine should use high octane fuel, 91 or 93. Manufacturer and manual both say that the engine is suited to use 87. The complaints that people have been posting pertain to detonation issues with 87 octane in the egine, causing plugs to melt.

Has any of you heard a case like this? With any turbo engine? Should I immediately just go for 91 octane starting now?
 
Originally Posted By: poiuy223
I've been reading the Hyundai forums and many are posting that the 2.0t engine should use high octane fuel, 91 or 93. Manufacturer and manual both say that the engine is suited to use 87. The complaints that people have been posting pertain to detonation issues with 87 octane in the egine, causing plugs to melt.

Has any of you heard a case like this? With any turbo engine? Should I immediately just go for 91 octane starting now?


I would bet your manual says your car need a minimum of 87 octane. And that a higher octane may improve performance.

I would run 93 octane. Wait. . . . I do run 93 octane! lol
 
Originally Posted By: PZR2874
They running the stock tune and 100% completely stock ?

If so, I'd do what the manual says.

All stock here.

Compression ratio: 9.5:1

Seems like majority still says to go with the manual, but some turbo owners are advising higher octane as cheap insurance.
 
Originally Posted By: poiuy223
The complaints that people have been posting pertain to detonation issues with 87 octane in the egine, causing plugs to melt.


If that is true, then it's your answer. Would you like to have detonation, melted plugs, and holes in pistons?

Maybe the 87 gas Koreans tested with is not the same as the 87 gas sold in USA?

Toyota had a glitch in early 2000's when they tested cars OK with Japanese gas (low sulfur) and suddenly their cars would smell like **** in US with high sulfur gas.
 
Originally Posted By: friendly_jacek
Originally Posted By: poiuy223
The complaints that people have been posting pertain to detonation issues with 87 octane in the egine, causing plugs to melt.


If that is true, then it's your answer. Would you like to have detonation, melted plugs, and holes in pistons?

Good point. Without actually taking out the plugs, how can I tell if they have been destroyed?
 
If they have been destroyed, you wouldn't be asking that question. You would already know.

The engines will run fine on 87 octane, but if the knock sensor reads detonation, the ECU will retard the spark, and you will be down on power. If you want max power, run premium.
 
Originally Posted By: gathermewool
93 is too high. 91 is what I'd run.

Does anyone run 89? Seems like 87 is to save money and 91/93 is for optimum performance.

But thanks guys, 91 will be the going forward fuel.
 
if it wasn't for US consumers, the imports would never try to get their cars to run on 87. Mazda introduced the CX-7 (turbo 2.3) requiring premium but had to detune it to run on low octane on later models because of the backlash.
Cadillac went through that w/ the northstar years ago; old lady caddy drivers resisted using premium.
I'd be willing to bet hyundai has the computer pull timing way back to prevent detonation (and giving up a good amount of hp) and using higher octane will allow the engine to run where it really wants to.
 
Originally Posted By: mpvue
if it wasn't for US consumers, the imports would never try to get their cars to run on 87. Mazda introduced the CX-7 (turbo 2.3) requiring premium but had to detune it to run on low octane on later models because of the backlash.
Cadillac went through that w/ the northstar years ago; old lady caddy drivers resisted using premium.
I'd be willing to bet hyundai has the computer pull timing way back to prevent detonation (and giving up a good amount of hp) and using higher octane will allow the engine to run where it really wants to.


Agreed!
 
Originally Posted By: mpvue
if it wasn't for US consumers, the imports would never try to get their cars to run on 87. Mazda introduced the CX-7 (turbo 2.3) requiring premium but had to detune it to run on low octane on later models because of the backlash.
Cadillac went through that w/ the northstar years ago; old lady caddy drivers resisted using premium.
I'd be willing to bet hyundai has the computer pull timing way back to prevent detonation (and giving up a good amount of hp) and using higher octane will allow the engine to run where it really wants to.

That's what some people are reporting too. You just end up losing HP. I don't really care for that since I can just use premium fuel to get that back...but the issue that is alarming is the melting of the plugs.
 
Originally Posted By: poiuy223
Originally Posted By: gathermewool
93 is too high. 91 is what I'd run.

Does anyone run 89? Seems like 87 is to save money and 91/93 is for optimum performance.

But thanks guys, 91 will be the going forward fuel.


Since you're in SoCal, I assume that 91 is the maximum octane that you can get for street pump gas, true?
 
If the tune is designed to run on 87, but will occasionally pull timing, then a higher octane is warranted. Using 91 over 87 will provide an engine with a tune designed for 87 plenty of margin to detonation. Heck, maybe they cut it close with the 87 statement, but 89 would be sufficient. In that case, even 91 would be overkill. However, if the engine never experiences any knock and adds full timing using 89 or 91, then 93 would simply be a waste of money, with zero value added.
 
Originally Posted By: gathermewool
If the tune is designed to run on 87, but will occasionally pull timing, then a higher octane is warranted. Using 91 over 87 will provide an engine with a tune designed for 87 plenty of margin to detonation. Heck, maybe they cut it close with the 87 statement, but 89 would be sufficient. In that case, even 91 would be overkill. However, if the engine never experiences any knock and adds full timing using 89 or 91, then 93 would simply be a waste of money, with zero value added.


Yes, but today's computers on todays cars and VVT can also advance timing, over time, to get even better performance and MPG.

I would give 93 a try for a few fill ups and see if there is any gain before I rule it out all together.
 
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