100 Octane

[cody.freeman1]

Is it alright to put 100 octane in the LLT (V6).......or is 93 octane what I should use for some performance boost?

[HondaPowered]

You get no performance boost, your engine is direct injection, therefor 87 should be perfect. If you want a "performance boost" get a nitrous kit or some other "performance" add ons

[Russell James]

Go into your bathroom and start flushing $20s.

Same end result.

The LLT is calibrated for 87.

[rollinhard]

If your talkin race gas or avgas as in LL100 I would think it is bad as it is usually leaded fuel and catalitic converts hate that stuff. My uncle poured some left over VP110 in his truck and his cats got so hot one almost was on fire.

[10spokess]

I only run 110 octane at the track but I also usually run out of gas trying to get to the track so that is my only option. I have no cats tho

[canadian ss]

It will only give you a very clean burn because its refined much better than 87. Google octane and cetane ratings and you will get a better understanding of fuel ratings and whats in it and what it does when you burn it.

[canadian ss]

Straight-run gasoline has an octane number of about 70. In other words, straight-run gasoline has the same knocking properties as a mixture of 70% isooctane and 30% heptane. Cracking, isomerization, and other processes can be used to increase the octane rating of gasoline to about 90. Anti-knock agents may be added to further increase the octane rating. Tetraethyl lead, Pb(C2H5)4, was one such agent, which was added to gas at the rate of up to 2.4 grams per gallon of gasoline. The switch to unleaded gasoline has required the addition of more expensive compounds, such as aromatics and highly branched alkanes, to maintain high octane numbers.
Gasoline pumps typically post octane numbers as an average of two different values. Often you may see the octane rating quoted as (R+M)/2. One value is the research octane number (RON), which is determined with a test engine running at a low speed of 600 rpm. The other value is the motor octane number (MON), which is determined with a test engine running at a higher speed of 900 rpm. If, for example, a gasoline has an RON of 98 and a MON of 90, then the posted octane number would be the average of the two values or 94.

High octane gasoline does not outperform regular octane gasoline in preventing engine deposits from forming, in removing them, or in cleaning the engine. Consumers should select the lowest octane grade at which the car's engine runs without knocking. Occasional light knocking or pinging won't harm the engine, and doesn't indicate a need for higher octane. On the other hand, a heavy or persistent knock may result in engine damage.

[Doc]

Octane doesn't "boost" performance. It's actually the measure of how much detonation retardant is in the fuel to slow down the burn. High compression engines run hotter in the cylinder so there's the possibility of "hotspots" in the compression chamber which can act like spark plugs, pre-igniting the fuel before the spark plug fires. This produces power-robbing engine knock and can actually destroy an engine. They put retardant in the fuel (marketed as octane) to make it impossible for these hot spots to ignite it so only the spark plug has enough heat to ignite the mixture. In a high compression engine (also boosted, forced injection, etc) this is critical to performance.

They assign an octane rating based on how much retardant is in the fuel; the more retardant, the higher the octane number. So it isn't the octane that boosts the performance; it just raises the flash point of the fuel so it doesn't pre-ignite. In engines that do NOT require this, (like your V6) the higher octane fuel won't burn as well because you don't have the heat in the compression chamber required to burn it completely so you may actually get less power. And you'll see more soot and un-burned fuel making it's way through your exhaust system.

87 octane fuel actually ignites quicker and easier than 100 octane does. If you can run on 87 without losing power because the ECU has lowered the engine performance to prevent knock (pre-ignition) then by all means run 87. The SS V8's can't run it without losing power; they have to run premium but your LLT V6 should run on it quite well. Saves money too.

[canadian ss]

Regular Unleaded Gasoline
The recommended gasoline for most cars is regular 87 octane. One common misconception is that higher octane gasoline contains more cleaning additives than lower octane gas. All octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against engine deposit build-up. In fact, using a gasoline with too high of an octane rating may cause damage to the emissions system.

• Gasoline and Octane Ratings - This article defines octane ratings and provides an overview of how gasoline in made.


Mid-Grade Gasoline
The octane ratings 'regular', 'mid-grade', and 'premium' are not consistent. In the United States, for example, one state may require a minimum octane rating of 92 for premium gasoline, while another may allow an octane rating of 90 to be premium. Check the octane rating on the yellow sticker on the gas pump rather than relying on descriptive labels.


Premium Gasoline
Certain high performance engines benefit from use of high octane fuel. For other engines, using a fuel with a higher octane rating than the vehicle requires sends unburned fuel into the emissions system and catalytic converter. This puts unecessary stress on the emissions system. For some vehicles, a rotten egg smell coming from the tailpipe signals use of too-high octane gas.

Leaded Gasoline
Many countries continue to use leaded gasoline, even though lead exposure has significant health and environmental consequences and the cost of switching to unleaded gasoline is relatively low. Although greatly improved, research indicates significant health and environmental effects from use of leaded gasoline remain even in countries that have switched to unleaded fuel.


Synthetic and Reformulated Fuels
Some major cities with air pollution problems require the use of reformulated gasoline. Reformulated gasoline is an oxygenated fuel that burns cleanly but can lower fuel economy and engine performance slightly. Reformulated gasoline may cause pinging or premature burn in engines with excessive carbon deposits. Older/dirtier engines may benefit from stepping up to the next grade of gasoline.

[canadian ss]

Will Higher Octane Gasoline Clean Your Engine Better?

As a rule, high-octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car’s engine. In fact, the U.S. Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

Should You Ever Switch To A Higher Octane Gasoline?

A few car engines may knock or ping — even if you use the recommended octane. If this happens, try switching to the next highest octane grade. In many cases, switching to the mid-grade or premium-grade gasoline will eliminate the knock. If the knocking or pinging continues after one or two fill-ups, you may need a tune-up or some other repair. After that work is done, go back to the lowest octane grade at which your engine runs without knocking.

Is Knocking Harmful?

Occasional light knocking or pinging won’t harm your engine, and doesn’t indicate a need for higher octane. But don’t ignore severe knocking. A heavy or persistent knock can lead to engine damage.

Is All "Premium" Or "Regular" Gasoline The Same?

The octane rating of gasoline marked "premium" or "regular" is not consistent across the country. One state may require a minimum octane rating of 92 for all premium gasoline, while another may allow 90 octane to be called premium. To make sure you know what you’re buying, check the octane rating on the yellow sticker on the gas pump instead of relying on the name "premium" or "regular

[E.T.]

This has been discussed in numerous threads. People will say there is no performance boost, but it has been proven that timing is being pulled when using 87 in our V6's. This equates to a loss in power. It was also shown that timing was not pulled when running 93.

The manual states: use 87 octane or higher. Many members have reported that the engine seems to run better/smoother with the higher octane. Not sure about the diff. (if any) between 93 and 100 octane.

Edit: here's one discussion--

http://www.camaro5.com/forums/showthread.php?t=111580

[cody.freeman1]

Thank you for all the responses and help Camaro 5. I enjoyed the flushing joke haha. Big thanks to canadian ss and Doc for your help and clarification.

[sooneRS]

LLT runs better with 91 or even 93 compared to 87.

[jeff4946]

I have the pleasure of working in a refinery, and even better, my job is to blend giant tanks of gasoline. A lot of what has been said is true, some is gibberish.

Without going into great detail... it has a lot to do with vapor pressure, as well as octane, but no such thing as being" refined more". Cleaners, or detergents, are added after the tanks are blended, and are defiantly not equal. Without mentioning where I work, I will say, Techron is a huge cut above the rest, and is only intended to clean intake and injectors. Not cleaning squat when burned.

If you are not boosting with Nitrous... 87 octane is what your car is tuned to run , and is what you should use, because the "knocking" part of all that up there is completely true. It will destroy your engine if you dont pay attention to it.

I run nitrous, and I use 91 octane with about a quart of Toluene. Runs good for juice, but a waist when not spraying... and will deposit carbon in you exhaust.

In short, "gas" is a blend of finished "cuts" off a column or cracked of a chain of carbons, then blended. There is no such thing as "pure gas". Different octanes are produced by the blends. And as far as the heavy straight part... heavy straight run is feed for a light end plant called a reformer , and isn't used for blending ,unless we have to much octane give away, and it is not clean enough, so we use the very next cut which is heavy light straight run. Heavy straight is too sour.

The egg smell is h2s, and I wouldn't buy that gas if they haven't stripped that out good enough.