Octane
 

What is the proper octane for a 1994 4Runner? 93 or 87?

What does the manual say about the 3vz engine and octane?

Thanks for any advise ...

manual says 87 octane or higher.

87 octane is all it wants.

i run 93 b/c i get better mileage and response
i would recomend 89 if you drive over 50 miles a day
i drive over 350 miles a week in town

...what makes you say use 89 octane for a lot of driving? the only thing it really does is make the fuel take more heat to ignite it, which prevents detonation in high compression and forced induction engines.

i conducted an experiment on my 22R-E to see if there was any benefit to using slightly higher octane gas due to the relatively high 9.5:1 compression, and there was no difference in feel between the two, and my mileage stayed the same. i'm buying 87 from now on, unless i need to tow my boat over the pass, then i might consider 89 to keep my engine from pinging under the heavy load.

Mine runs best on Black Butte Porter.
No, wait, it's me that prefers beer...

Yeah, one of the most misunderstood things in all of autodom is octane ratings. HIGHER IS NOT NECESSARILY BETTER.

Higher octane fuel actually has LESS energy than lower octane. This is more than made up for with high compression ratios on forced induction engines (especially turbos due to the ease of adding wastegates).

You should run the MINIMUM octane that prevents preignition (at full boost for the forced induction guys).

no kidding. it's like my boss who says he needs 92 octane in his '78 dodge pickup with a 318 to get the most power. that thing would probably burn kerosene, and it's only got probably 8:1 compression!

just goes to show how much of a placebo effect it really has...

Just to chuck in my 0.02 but I've noticed that with my 3.0 if I run 87 the engine turns about 3000 to give me 110Kph, if I run 93 it only turns about 2600-2700 to give me the same 110 Kph. This on same highway same time of day same load similar weather conditions. it runs fine on 87 but just seems to run a little better on the 93. (not that I can afford it all the time). I also pick up about 40 more klicks to the tank too. Any thoughts?

I don't think the choice of gas octane will automatically change the gearing of your truck??

Nothing more than octane doesn't change the gear ratios.
Running 2 much octane raises emessions, and while I'm the last person to care - being I live in Alabama & we still ahve an environment that can deal with pollution - so I dont' have any EGR, or cat myself...
It also decreases power if the engine isn't tuned to run it.

If the Toyota book says:
Select Research Octane No. 91 (Octane Rating 87) or higher.
It could also say:
Select Research Octane No. 91 (Octane Rating 87) or higher. For improved ve3hicle performance, the use of premium unleaded gasoline with a Research Octane No. of 96 (Octane Rating 91) or higher is recommended
Lastly:
Select Research Octane No. 96 (Octame Rating 91) or higher.




All Toyota engines say:

Gasolines containing MTBE:
Gaolines that contain MTBE (Methy Tertiary-Butyl Ether) are avalible in the market. if you use a gasoline mixed with MTBE, make certain that it does not contain more than 15% MTBE.
If the use of gasolines containing MTBE causes poor drivability and/or poor fuel economy, you should stop using them

Gasolines containing alcohol:
Gasohol is a mixture of gasoline and ethanol. If you use gasohol in your lexus. be sure that it is unleaded, has an octane rating no lower than (Insert your octane here) and does not contain more than 10% ethanol. lexus does not recommend the use of gasolines containing methanol.

If you use gasoline containing methanol, use only gasoline meeting the requirements above and also not containing less than 5% methanol with cosolvents and corrosion inhibitors for methanol.











Anyways I digress.
Use the lowest octane possible that the engine does not knock on. If your engine knocks on 87... Retard the timing until it stops, deal with at most a couple (couple = 1, or 2) peak horsepower loss, and repeap the savings of 20-50 cent cheaper gas!

To clarify... With the higher octane I don't have to use as much throttle to get the same road speed, so my rpms are lower. :hillbill: It also seems more drivable with the extra giddy-up too :hillbill: :hillbill:

with the price of gas i only get 87 is $2.31 and 91 is like $2.91

While it may indeed be true that you need less throttle position to make the same speed, the engine RPM will be the same as it is directly linked to the speed of the vehicle by the gears in the diffs, transfer case, and tranny.

I am not disputing what you say and feel - just saying there's no scientific basis behind it...

another twist to the question:
i've found this winter, for the first time, i'm able to run 85 octane with MTBE, without knocking. and this is up and down the mountain to play in the snow. can this be due to my finally finishing the cat back, and with the headers and airbox mod, i've got better flow? in other words, can these upgrades effect pre-ignition?
or is it more due to the MTBE in the winter gas, and i just didn't recognize this before?

i wish we got 85 here -- i'd run it in my hybrid. doesn't ping a bit after i put the weber carb on and richened up the mix proper.

i've thought of filtering the waste gas bucket we have at work(all kinds of wonderful stuff in there, ancient lawnmower gas, used laquer thinner, 2 stroke mix etc) and burning that up.

the kicker is out here we can get 85, but we pay what you pay for your 87. and our 87?--your 91 price. don't ask about our 91.