100 octane?

KGB4187

New member
Would filling up with 100 octane make any significant increases in performance? Saw its only $5.69/gal not too far from here but thought it might mess up the engine. Any idea if its worth it?
 
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worth it for performance?

Short answer:
No.

Long answer:
contrary to what the oil companies would like you to believe, you actually get better performance with 87.

lower octane = easier to burn. the idea is to get the lowest octane possible BEFORE you detonate..becuase then the ECU will re**** the timing and cause poor performance.

Abe
 
100 Octane


'Only' $5.69???? Wow!

That is probably aviation gasoline, so be careful. AVGAS contains lead, which is illegal to use in your 4Runner and could harm the engine.

I doubt you would see any enhanced performance, so save your money. Fill it up with pump gas rated at '93' and pour in a bottle of Octane Boost and you'll get the same result. 100 octane is overkill and unnecessary for your truck.

Cam 2 fuel and other racing gasoline is best for older engines with very high compression ratios (such as 12.0:1, etc.).

My friend had a customized 1969 427-powered Chevelle that needed it, but it was pushing 620+ horsepower and he drag-raced it. It would not run on unleaded "pump" gas, unless he poured additives into the tank beforehand.

My 4Runner ran just fine on 87 octane, so I do not see how the huge extra cost of super-high octane gasoline could be justified for this type of vehicle.
 
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Just to clarify we are talking about a 4th gen, correct? If so it's been proven that the 1GR-FE's ecu will make use of higher octane fuels, but it does take it several tanks to adjust. Higher octane means better timing, which also leads to better efficiency.
 
It tops out at 91 octane though, and it adds 6 hp. It doesnt run any cleaner or otherwise better, and in fact will get slightly worse MPG (91 that is).


some exotic fuels do not have the same burning characteristics as normal gas, leading to relatively poor combustion at idle and mid throttle... I'm positive you'll notice a difference if you load up with 100. but it won't be a good one, unless you want to shave your heads first to increase combustion...

and its worth noting the timing for power and efficiency arent the same. higher octane gas does not equal higher fuel economy.
 
I can think of one advantage... The shelf-life of highly refined, non-additive fuel is substantially better. If you were going to park it for a year or more it might be a good choice. Back in the day Amoco 'white-gas' was sought after for a variety of reasons including shelf-life. Modern 100 Octane Racing unleaded is the closest thing you can find these days. Someone mentioned AVGAS. To my knowledge that's been outlawed even for off-road vehicles. It's still in airplanes because so many engines still may not have the correct valve guides and no other gasoline has a shelf life like 100LL AVGAS.

Power... The computer will adjust some but without learning that Isreal or some place has the same engine computer, 100 octane and a horspower rating higher than the US FJCruiser on premium I doubt it can adjust far enough. IHMO:biggrin2:
 
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Sorry for the vague post, it was late. I have an 05 V6 and it was race gas from a 76. I figured it wouldnt be worth it but after 50 miles of fun roads it sounded good. Around here premium (91) goes for $3.85 for the cheap brands to $4.07 for Shell/Chevron/76 stations. In parts of SF and Oakland I've seen premium go for $4.47 so 5.69 isn't that much of a leap...
 
ive run 100octane in the 4runner and off idle throttle response is improved along with midrange power but it does come with a downside of lower economy.

CHT's should be slightly higher with the 100octane and as such should help to burn up carbon deposits.

I havent used it in a while but might try a tank as right now im only getting about 20mpg combined highway/city.
 
Higher octane gas is used where very high cylinder pressures will be produced to prevent pre-igniton and that's where the gas will ignite before the cylinder reaches top dead center and the plug fires. This is caused by lower octane gas being used in like a turbo or SC'd car. Higher octane is less volitile and will ignite when the spark fires and not before but using higher octane that is required is a waste since it does absolutely nothing else to increase performance.

Cylinder pressure never gets that high in a stock 4Runner and even SC'd they don't require that high of octane to run properly unless you're really boosting it.
 
CJ3Flyr said:
Back in the day Amoco 'white-gas' was sought after for a variety of reasons including shelf-life.

They still sell Amoco premium at "BP" stations. The main advantage with this gas is, there is no dye used to identify it as premium (therefore "white/clear gas"). This dye ends up causing residue and/or carbon build up.

Koz
 
Koz said:
They still sell Amoco premium at "BP" stations. The main advantage with this gas is, there is no dye used to identify it as premium (therefore "white/clear gas"). This dye ends up causing residue and/or carbon build up.

Koz

True but you'd have to buy it the summer in some places and in others it's not availible as true, pure (with an incredible shelf life) gasoline. EPA's seasonal requirements and the addition of alcohol and other additives. That applies to all the gas including that from the BP. Coleman fuel and 100 Octane race gas are about the purest, longest lasting gasoline on a consistent basis.
:cheers:
 
CJ3Flyr said:
True but you'd have to buy it the summer in some places and in others it's not availible as true, pure (with an incredible shelf life) gasoline. EPA's seasonal requirements and the addition of alcohol and other additives. That applies to all the gas including that from the BP. Coleman fuel and 100 Octane race gas are about the purest, longest lasting gasoline on a consistent basis.
:cheers:

Shelf life seems to be very important to you so here is a product that is a one time device that insures gas stays fresh!

http://www.fitchcatalyst.com/index.php

Koz
 
But now it is rediculous silly to put anything except current price gas with the proper octane rating in your 4Runner.

So,when gas is really $5.50 will people be so willling to throw in 100 octane when it's almost $8/gal.?
 

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