Pitbull

I did a search but did not find anything on this subject? Can't believe I'm the first one to ask. Maybe I'm doing something wrong on the search? Oh well here's my question.

With the price of fuel, how low can I go on octane rating? I don't want to harm my engine or my gas mileage. I know Toyota recommends 91 octane. In my area regular is 87, midgrade is 89 and premium is 91. What are you other 4th generation V-8 guys/gals doing???
Thanks

Taints2k3

I use 87 in mine and no problems with MPG/Performance..If I remember correctly I beleive the manual even says 87.

dcampen

Um, that is not what I get from the manual. The way I read it they recomend 87 octane but allow that if you feel that 91 octane gives better performance then it would be OK if you want to use 91 octane. I use 87 octane. If I was expecting to be towing a heavy load on steep mountain roads at high altitude then I would probably fill up with 91 octane.

Biff

This has been discussed many a time. 87 is the standard

kenandjenn

Higher octane itself will NEVER produce more power from any engine. It can actually lower your power. Higher octane makes the gasoline have a higher flashpoint, which makes it harder to burn. MOST N/A engines need nothing more than good quality 87 octane for optimal performance. With advanced timing, high compression, or boost, higher octane is recommended to reduce detonation. Detonation will hurt power, so only in this aspect can more octane help the power output of an engine.

BT17R

2UZ has knock sensors that might allow more power and better economy on premium grade 91 octane. Might. It depends on whether it knocks on your brand of regular. Also, if you're at altitude, higher octane is unnecessary in an N/A engine.

I'm at sea level. My old Tundra ran fine on regular and never knocked. But my FJ-100's knocked so I switched to premium and gained around 1 mpg, too. The 2UZ is tuned differently for those applications. I always ran premium on my 4Runner, but most everyone here has been fine with regular grade.

HBoss

I think he meant "Premature-Detonation will hurt power". He's right...the octane does not boost power. But pre-detonation will certainly reduce power and ruin your engine. You should always use at least what your manual recommends. Often enough you'll have to go higher octane as the engine mileage gets up there and you're closer to sea level (altitude).

tom4416

Toyota does not recommend 91 octane. Toyota recommends 87 octane but adds that you may notice increased performance on premium. The engine has enough sensors to avoid knock and so may advance your timing some on premium, perhaps yielding a tad more power but I've tried both in the V6 and no noticeable difference in gas mileage or performance. Good thing, premium (93 octane) is up to $1.79 in Virginia while regular is $1.59 and climbing. I know, I know, I've got nothing to complain about since the news is constantly showing Calif. at $2.00+ per gallon but then, we don't have the excitement of earthquakes, forest fires and mud slides in Va. :~)

bulldog-yota

I run an premium with mine, and pretty happy with the performance and mileage. Have not tried 87. The way I read the manual was 91 recommended but 87 will work. Probably need to check it again.

Also remember the higher the altitude the less the octane requirements become for most vechiles (thinner air less air coming into comb chamber less pressure I would think). At sea level I would say 91 would be good, at higher places 3000 feet + less should be fine.

The only way to tell is run a couple tanks on 87 and then a couple 91 and see what works for you. You shouldn't have knocking with the engine as it has a pretty advanced engine management system.