Premium gas or regular

[Sparko]

Originally Posted by mikeman

If that's true, then why do people always say that it's okay to run 87 and anything higher is a waste of money? Not that I'm disagreeing with you, I'm not, but just what people around here say when stuff like this is mentioned.

Because if you are not upping the octane for purely performance gain it is a waste of money. Higher octane is more resistant to ignition which decreases fuel economy and starts harder in cold weather. If you put anything other than 87 in a car that can operate on 87 to go get groceries and/or put-put around you are wasting money. If you're ripping up the road operating at WOT, that is when high octane is useful.

[CamaroBarb]

The fact is the v6 engine is no different than the v8 engine when it comes to fuel. The only reason you can use regular in either one is because the computer pulls the timing out.
This goes for the LLT LFX and so on.

[CamaroBarb]

Originally Posted by Sparko

Because if you are not upping the octane for purely performance gain it is a waste of money. Higher octane is more resistant to ignition which decreases fuel economy and starts harder in cold weather. If you put anything other than 87 in a car that can operate on 87 to go get groceries and/or put-put around you are wasting money. If you're ripping up the road operating at WOT, that is when high octane is useful.

Back when compression ratio's were 8.5 to 1 yes but the fact is if you put regular in your v6 or v8 11 to 1 compression ratio engine the computer pulls timing so it doesn't ping detonate and destroy itself. AND GDI engiines are prone to Low Speed Pre Ignition. So at low engine speeds using regular the computer actually pulls the timing NEGATIVE to try and prevent it.

[gtstorey]

Even if the car only has the low octane table, it's still "safe" to run the higher octane gas. I think a lot of people think that high octane means more "power" in the fuel or bigger explosions in the cylinders, hence "unsafe" to run in motors not designed for it.
To the O.P., don't let this discussion of high and low octane tables throw you, within reason, it will be "safe" to run higher octane in a vehicle that is designed to run well on lower. There may be some special race gas with a very high octane rating that may not run well, but even then its's probably "safe".

[ariZona28]

Does the LFX in my '15 have a "table" to take advantage of 91 octane fuel? Car is completely stock, no mods or tune work done. How can I check/monitor timing. Gone are the days of hooking up the Craftsman timing light and eye-balling the marks on the harmonic balancer.

[Badbubba]

Originally Posted by CamaroBarb

Let me explain it in terms you may understand. Your v6 Camaro has 2 yes 2 timing tables programmed into the tune. If you use REGULAR fuel it will use the low octane table, if you use PREMIUM fuel it will use the high octane table. So you can use either one, your choice. There are benefits to using premium fuel like more detergents, better fuel mileage and better performance. Your experience may be different than other, all cars are slightly different. Good Luck.

In my v6 premium makes a huge difference.

OP displays the ownership of a 2011 LS. Therefore that engine is a LLT. In 2012 the LLT was replaced with the LFX. The LLT tables differ from the LFX tables by not having 2 tables. The ECMs are different. The Bosch ECM for the LLT will continue to ramp up timing until it detects knock, then back off. In the LLT, add the premium fuel and drive somewhat aggressive to adjust. If there are better detergents in the premium fuel used, they will do nothing to help with the coking of the intake valves. Which might be the issue for the CEL.

[ChibiBlackSheep]

Originally Posted by ariZona28

Does the LFX in my '15 have a "table" to take advantage of 91 octane fuel? Car is completely stock, no mods or tune work done. How can I check/monitor timing. Gone are the days of hooking up the Craftsman timing light and eye-balling the marks on the harmonic balancer.

Yes, but just putting premium in once won't reset your fuel trims and put you into that table. If you put premium in, unplug your battery for the night. Or else you'll have to run a few tanks through before you start to have any difference.

You can check timing with an OBD2 program or HPTuner software.

[pyroguy]

Originally Posted by mikeman

If the factory tune has two fuel maps, low octane and high octane (like ChibiBlackSheep mentioned) then wouldn't it be better to run the higher octane fuel if you wanted better performance?

Yeah, I realize the V6 is not really considered a performance engine, but the driveability will be a lot better on the higher grade fuel. Many years ago, I used to have an old '76 Buick Century 350 that always ran better on high grade fuel than the low grade stuff. And, that was a low compression smogger motor.

Run what you want, but it is set up to run regular as the optimal fuel. Additionally, other than the two being internal combustion engines, your Buick 350 and Camaro V6 are about as different as they come. Comparing the two of them and how they react to the different octanes isn't a real good comparison.

[CamaroBarb]

Originally Posted by mikeman

Yeah, I realize the V6 is not really considered a performance engine,

Its not just considered a Performance engine, its considered a EXTREME performance engine! 326 HP from 217 cubic inches NA is outrageous. That's 1.5hp per cubic inch! By comparison the l99 SS only makes 1 hp per cubic inch and the LS3 only slightly more. Don't kid yourself putting anything other than the best fuel in the engine is no different than putting regular in a SS or ZL1. They are all High Performance engines with ultra high compression. Don't believe it please read the specs on all these engines. The compression ratio, hp rating and cubic inches don't lie.

[Badbubba]

Originally Posted by CamaroBarb

Its not just considered a Performance engine, its considered a EXTREME performance engine! 326 HP from 217 cubic inches NA is outrageous. That's 1.5hp per cubic inch! By comparison the l99 SS only makes 1 hp per cubic inch and the LS3 only slightly more. Don't kid yourself putting anything other than the best fuel in the engine is no different than putting regular in a SS or ZL1. They are all High Performance engines with ultra high compression. Don't believe it please read the specs on all these engines. The compression ratio, hp rating and cubic inches don't lie.

The hp difference per cubic inch is due to the 3.6 being direct injected. The advantages of DI also allow for 87 octane to be used to achieve rated hp. The compression ratio for the LLT is 11.3 and for the LFX is 11.5. Which is not extreme for DI engines, it is on the low side. Mazda, for one, is running 13:1 and 14:1 static compression ratios for their DI engines.

[mikeman]

Originally Posted by Badbubba

The hp difference per cubic inch is due to the 3.6 being direct injected. The advantages of DI also allow for 87 octane to be used to achieve rated hp. The compression ratio for the LLT is 11.3 and for the LFX is 11.5. Which is not extreme for DI engines, it is on the low side. Mazda, for one, is running 13:1 and 14:1 static compression ratios for their DI engines.

Wow.. That's getting up there almost into diesel territory.

I wonder how far they can go before the fuel just self-ignites?

[KenKat]

Originally Posted by Badbubba

The hp difference per cubic inch is due to the 3.6 being direct injected. The advantages of DI also allow for 87 octane to be used to achieve rated hp. The compression ratio for the LLT is 11.3 and for the LFX is 11.5. Which is not extreme for DI engines, it is on the low side. Mazda, for one, is running 13:1 and 14:1 static compression ratios for their DI engines.

That plus dual overhead cam and 4 valves per cylinder.

[SSEssence]

premium gas only, the highest octane available

[CamaroBarb]

Regardless what the engines are any engine with 11 to 1 compression needs premium. Only way you are running regular is if they cripple the timing.

Again 323 HP from a 217ci engine is extreme performance and needs premium, GDI or not. LLT LFX l99 LS3 doesn't make any difference. These are all HP engines.

GM is careful not to call the v6 High Performance for good reason. Its their economy Camaro engine, they do however call it their High Feature engine<makes me laugh. It makes 1.5hp per CI much more than their v8 @ 1hp per ci. Which one do you think is a high performance engine.