Juggalo

Just wanted to make sure...

I've always been using 93 octane gas for whatever I drive, regardless if it says 87 is ok.

Am I wasting money for nothing? I always think to myself that 93 octane helps keep the fuel system cleaner for a longer period of time, and that it helps for acceleration just a bit (which the 3.0 lacks a lot of)

So what do you guys think, will it run any worse on lower octane fuel?

Mike Murrell

What does your owners manual call for?

Use that octane rating.

Higher octane doesn't clean any better unless you believe the propaganda pushed at you by the oil conpanies.

Most of today's vehicles run on the lowest rating - 87 in most; lower at higher altitudes.

My 2 cents.

Yoter

My 3.0 loves Supreme fuel & especially when I throw in some FS cleaner. I ran MidGrade last fill up and god im paying for it. The Supreme makes the 3.0 run smoother but gives me throttle response. The lower you go in grade the slower you go every day IMO. Cant wait to run what fuel ive got out this weekend while muddin so I can put the "good stuff" in it.

Blue

Yoter

yeah they run but how well/smooth?

MTL_4runner

The higher octane gas does have some cleaners in it but it is no different than running some fuel injection cleaner every now and then. There is a myth that high octane gas has more power than lower octane gas.....NOT TRUE. The higher octane gas may allow a higher compression modified engine to run smoothly (and thus make more power) but it will not do much for something that is completely stock. For instance high octane gas may help to lessen the pinging that happens with a supercharger but the gas itself is no more powerful. The trick is to run the lowest octane gas that your truck will accept and still run smoothly. If you do experience pinging, then move up to the next octane level.

AverysDad

higher octane gas only benefits engines with a higher compression ratio......

such as sports cars for example. ive tried running higher octane in all the vehicles ive ever owned and have not ever noticed an increase in mileage or power.

i say put in what manual recommends (most likely it says 87 octane) and save your money.

Brendan

switching grades isn't good either. pick one and stick with it. if your engine isn't getting a high enough octane gas, it will usually diesel (continue to run) after you shut if off. other things can cause this, but low octane fuel is the first thing to look at.

MTL_4runner

The dieseling is from cabon buildup and a lack of cleaners in the fuel.
Once you get carbon buildup running a high octane fuel is a bandaid.
Running an injector cleaner like techtron will solve this.

Yoter

TECHRON RULES ALL! oh & Blue loves it BTW!

Juggalo

Same here, though I haven't put any additives in yet. I have tried 89, but it just doen't feel the same

I belive in the saying "you get what you pay for"

Jboy

I was always using high octane until gas prices increased. Now I`ve been using 87 for the past 3 years and I`ve noticed no decrease in performance or anything else other than getting more gas for my money.

Lahaina, HI Gas price for 87: $2.33

Fink

I think I am going to be switching to the premium gas...after this pinging sound I've been hearing I think I may try the premium stuff and see what it does for me...

JBoy - $2.33???? Wow...

Fink

Los Gatos?

Stick with 87 in your stock 3.0 unless you have pinging. There's no reason to spend more money on gas unless you have to, 91/93/94 is no better than 87 if your truck is tuned to run on 87. 3.slows are not running 12:1 compression or using forced induction.

Juggalo

Why not?!?!:cry:

FireMan

I used to have a 65' Pontiac Catalina w/ a 421 and triple duces. For anyone who haas never seen a carburated engine, that means (3) 2-barrel carbs all linked together. Kinda like a 4 barrel but with one more 2-barrel carb. I digress.

So, I could not run anything under 92. I was all ORIGINAL. I had to add the lead additive and all. The "diseling: SizzleChest talks about it called detonation. This occurs becase there is unburned fuel left in the cylinder. If you run a fuel, shuch as 87 octane in a high compression engine, bad things happen. The lower the Octane rating, the less pressure it takes for the Air/Fuel mixture to spontaneously ignite. The higher the octane, more compression is required to get the Air/Fuel mix to ignite.

Hence the high performance sports cars need 92+ Octane Only because they might have the same displacement and the average car, but the engine is set up for higher compression = MORE POWER !

The 3.slow should run fine on 87. There is NO NEED to buy anything higher. The bad thing to do is run lower than what you need. The detonation could be from bad spark plugs, leaky injectors, ect. ect .ect. Either way, unless you have a race car, go CHEAP!

MTL_4runner

Dieseling occurs only after you turn the ignition off yet the engine continues to run for a (hopefully small) period of time later. It was more common on carbureted engines and can only happen on an EFI if you have a seriously leaky injector(s). It comes from carbon deposits in the engine which become red hot and act like a glow plug igniting any fuel that enters the combustion chamber.

Pinging or detonation is a similar phenomenon, but the two should not be confused. Detonation occurs with the engine running and the fuel is ignited before you want it to (ie before the spark happens). It may be a suffiient combination of heat and pressure to set it off or it may be also from heated carbon deposits similar to dieseling. This is where the high octane gas does help a bit because the flame front (ie the speed of the gas exploding in the chamber) moves slower. If the was was ignited before you wanted it to, then the slower flame will make the time between when you asked for it and when it should have ignited (by the spark plug) will be relatively smaller.

Have I sufficiently confused everyone yet.

nolongeraneqaddict

i run 87, but i usually get it from Shell, Chevron, 76, i can notice a differance between Shell and say ARCO, its just a lot smoother.

chuckd

I run 87 and it's fine. My 69 Chevelle and Q45 however would always run noticably better with the good stuff. I've heard that some Mitsus actually run better on the cheap stuff. But 87 works for me.

My99

Everyone who's running higher than needed ocatane fuel needs to do some reading. "cleaner burning" <---- horsemess! Unless you're pinging, yes, you're throwing away money. If you're pinging and you're running the correct grade gasoline, as someone else stated, you have a bit of a problem to begin with. However, with today's gas prices, throwing away an extra 20 cents per gallon is the discretion of the wallet holder.

Yoter

I am not sure about the numbers but is it like this:
87=regular
89=mid
91=supreme

I dont pay much attention to the octane ratings. I just grab for mid or supreme. I dont put regular in because even with mid sometimes I get a sluggish feeling while driving. If I put supreme in its not so bad. Its a little hard to be saying whats what this time of year anyway. I mean the fuel sucks with the crap thats in it right now. But I seriously can see if you put regular in that you may get that pinging sensation aswell as lower fuel efficency. Im not a brain surgeon like some of you that know so much about fuel but I do know what feels right when I drive my vehicle.

Blue