i found a gas station that pumps out 100 octane fuel($7.99/gal), i put 3 gallons of it to see how it would feel. it made a lot of difference! im just wondering if i'm doing harm to my injectors or to any other parts in the engine?

 

i put 110 in mine when i went to the track... it most deff ran faster but my cel came on after I used it all .. lucky i didnt burn a fuel like it smelled like straight alcohol.. lol

 

So what does that much octane actually do?

 

the good thing about higher octane fuel is that it burns hotter and will burn out carbon and gas varnish, higher octane ignites later so it will combust at a more efficient time in the power stroke because because it won't ignite from too much heat or pressure. It's basically fuel that is harder to combust by compression got it?

 

you guys....that is all in your head. without a tune for the higher octane, you are actually just burning the fuel less evenly, and you are either making the same power, or you could even be making less. Plus, you are not cleaning up carbon deposits, you are making them because of an uneven fuel burn. and you don't use higher octane fuel because it burns hotter...let me explain something.

iso-octane(octane), or the eight carbon chain, has more tolerance to compression and heat than the other hydrocarbon's and carbon chains in gasoline, so the more of it there is, the higher heat, and compression you can run without detonating/knocking. This allows for more extreme conditions inside the engine without adverse effects on internal engine components. Basically, with a tune for higher octane fuel, you can get more power out of the same setup because of a more aggressive tune, while keeping the same safety. With your stock tune which i beleive is for 93, your ecu will automatically drop some timing if you use lower octane gas because it will detect knocking, so you will lose power with lower than 93. You are not going to make more power with higher octane though, because your tune is not going to change at all the higher you go over 93, which is where the extra power comes from when you use higher grade fuel. If you guy too high (like 100 and DEFINATELY 110) your tune is likely, "too mild" for that fuel, and the fuel may not burn evenly which is what leads to carbon deposits on top of your piston and other problems. run 93...you are just wasting your money on anything higher unless you are tuned for it or if you want extra safety with some mods run something just a bit higher than 93 or 91, whichever you are tuned for stock, but like i said before, don't go too much higher than your tune is for, because you are just wasting money. T

 

yea good point, if you have a tune for a higher octane than 93 its fine... but without the tune like u said its almost pointless

 

thanx for detailed breakdown.

 

Yeah, I learned in college that octane is the resistivity of the fuel to combust. I finally get to apply that somewhere! lol

 

Well 8cd03gro seemed to hit it pretty spot on. I'm amazed how many times these post come up on different boards. If your car doesn't need the extra octane the only performance you are getting is a lighter wallet. And if you insist on putting in the high octane stuff steer away from leaded gas. It'll kill your o2's.

 

Its a measure of resistance to detonation, or pre-combustion due to heat or other externalities.

The higher the octane, the higher the measure of resistance to that. It's good in that it is more resistant to engine knock on most high hp cars and what not but useless for the average joe.

 

Like said above higher octane does not help if it is not tuned for. My bro's 84 monte ss sbc 350 with 8.5 to 1 compression ran hard on 87 octane. But when we put 93 in there thinking more octane more power the car ran like **** and was definitely slower.

 

definitely with 8.5:1 damn. But your car ^^^^ will run harder.. since it's tuned to run on the ragged edge of 93 octane (has meth injection to help that) through in 100 and it'll run even better.

 

lol i thought it was better because it burned hotter and cleans the engine?

Most of what everyone is saying is correct, but a few pieces of information are being left out. Higher octane is used to resist detonation. Detonation is caused because the gas/air mixture in the cylinder ignites before the spark ignites this. This occurs doing the compression stroke, so you can on imagine the strain it puts on the engine when while its trying to force a piston up, the piston majorly refuses to move, and puts pressure on the entire engine. Just remember this Heat+Compression=Detonation

93 octane is pretty useless if your using any stock GM parts, so stock, stage 1 and stage 2. But if your running a smaller pulley your putting more air into the engine which does a few things.
A smaller pulley means the supercharger is working harder, this creates more heat, the hotter air is going into the engine.
A smaller pulley also means more air is going into the engine, the more air you cram into the engine, the higher the compression is going to be.

I honestly suggest anyone with a smaller than Stock size tune pulley run a 93+ octane atleast at the track to get your best times. So basically you can use higher octane as a patch for a bad tune.

 

ummm... completely contradicting yourself? at first you say you ran faster, then you say it's pointless after you are corrected. not important... just seemed odd.

Anyways, I dont know where people keep getting the misconception that higher octane = more power. As everyone else has stated, it just allows you the ability to run a more aggressive tune.

 

the ONLY TIME you are actually going to want to run higher octane than your tune is for (and only a bit higher, but its a good idea just to be safe) is if you are going to be hot lapping like a bitch. Wether it be at the strip or on a road course, if you think you are going to be hotlapping like crazy, which i'd advise against anyway, you may want to use the next level up in octane rating. not from 93 to 100, but if you are tuned for 91, you should use 93 just to be safe because you are going to be running much higher temps by hot lapping.

 

I had a tune for 100 octane not 110 so it did help me out... I would have just put 100 octane but it was the same price so i figured what the hell

 

Will 100 octane hurt our cars??? well a stock one??? im not one to try something on my car since it will be turned in, in about a week. but my friends wants to run it in his stock ss/sc.

 

no it wont "hurt" it, but there is just no point unless you are tuned for it...it's just a waste of money, and 100 octane is pretty expensive.

 

Won't hurt unless it's leaded like stated above, but you'll see NO gains and in fact you could even lose a couple hp with stock timing. It's not worth anything if your car doesn't need it.

 

Strongly disagree with that statement.

I have stage 2, Intake, Exhaust.

and My aeroforce gauge tells me that 91 octane = 4-5* of knock
94 octane = 0* of knock.


that would suggest that 93 octane is far from useless.

 

I strongly agree with your statement here. With stage II, 93 is probably perfection.

 

I think you mean pre-ignition here........there is a difference

 

sunoco 93 has alcahol in it, and leaded gas will burn out your stock valve guide seals.

 

Does octane booster work?

 

technically, yes it does "work," but not well enough. Say you add a bunch of octane booster and do the math so it works out to be 100 octane....well the problem with octane booster is it is not a perfect solute for all gasolines, so some areas in your gas tank will get more concentrated amounts of the booster than others meaning you are gonna be injecting the equivalent of 100 sometimes and maybe 95 others, so tuning for pump gas with octane booster is a bad idea. You are better off mixing race fuel into your tank.