Gas ? Octane ?

[badcertified]

 

Hi You All , I'been reading some thoughts on Gas and Octane . I was always under the assumption the higher the Octane the fuel would burn Hotter , therefore Cleaner , . What I have been reading on this post say's i'm wrong ! What is the general idea for best brand and best Octane for 5.7 in a 98 silverado. Thank you in advance ! P.S. I love reading these posts , you guy's know a lot about GM Trucks . Also is Citgo that bad , been using it .

[robsawatsky]

In general, unless your engine pings/knocks, run it on the lowest octane recommended by the manufacturer. Higher octane rating does not mean burning hotter or cleaner, in fact it could be the opposite. However, several brands increase the amount of fuel system cleaning additives in their higher octane blends, which does not mean cleaner burning in term of pollutants but clearner in terms of deposits in the fuel system, injectors and engine components. I think it a gimmick to get consumers to buy more expensive premium when it isn't needed and all the major brands claim their regular grade has all the detergents needed.

 

There are a few engines/engine control computers that will adjust their timing to take advantage of higher octane and protect against engine knock but most typical engines the regular timing is set for the recommended octane even if they have knock sensors to retard timing if knock is detected.

 

Anyway, burning hotter doesn't equate to cleaner. Engine combustion chemistry is much more complicated than that with all sorts of trade-offs between the various pollutants generated with higher/lower combustion temps, leaner/richer mixtures, etc, etc.

[95_togo]

i use LOW grade in my 95 5.7 haven't had a problem since it was new!

my mustang MUST have super unleaded -- ironically enough, i tried the chevron with techron to help "clean the inside" as their ad says but the car pings terribly with chevron....with texaco super it purrs like a kitten-- there are a few others....i think the car runs pretty good with phillips 66, and 76. you really should experiment on your own!

but like said earlier....use the lowest octane recommended by the manufacturer -- or the lowest octane you can get away with and not degrade performance.

 

[01Burb]

Octane is a hydrocarbon with 8 carbon atoms chained together. Methane, butane, propane, heptane are all similar organic compounds. Octane is your common gasoline.

 

The Octane rating however is also a level of knock resistance of the gasoline. The lower the rating the less resistance to knock. In a high compression engine you need a higher octane gasoline.

 

There is NO advantage to putting 93 in your vehicle if the manufacturer recommends 87. You will NOT go faster nor will it benefit your engine.

 

Similarly, in a modern higher compression car engine, accidently putting in 87 instead of the recommended 93 will not damage the engine as the computer will advance/retard timing as necessary to reduce knock. Your performance will suffer somewhat.

[Black02Silverado]

I can say this much. I just put 12 gallons at a total cost of $40 of BP gas that has 100 octane on the pump, in my 65 Impala with a 10.5:1 compression engine and it makes it run sweet. Not to mention the exhaust smells like I'm at an NHRA event.

 

The fuel has a blue color to it in my fuel filter.

[MCourson]

We used to run Cam 2 and VP red in the karts before we ran methanol. The Cam 2 smelled nice, but the VP was normal. I liked the Cam 2.