Gas Octane

Anything above 87 is a waste unless you have the supercharger, or you raised your compression somehow. High octane is for high compression engines. Your owners manual wouldn't lead you wrong. Though you're not hurting anything by running a higher octane either, so if you have money to burn (pun intended) have at it.

 

I work at 3800 ft, live at exactly 6000 ft. All out gas stations are 86/88/91. All the science says you are supposed to need less octane at higher elevations...but my baby just don't like the 86. I run 88 in town and average 17 high, mid 18s. I run premium on long road trips as the speed limit out here is 75 and I average just over 21 (barely high 19s on 88).

 

i run 91/93, i think its best for my truck and it responds well with it. i put race gas in a few times just to see if it did anything and did see an increase in mileage but it wasnt worth the extra money spent.

 

I run regular(87) in winter and premium(91) in summer. If I run regular in summer, I get "rattling" slight predetonation on level, no acceleration driving. Weird, I know With everything being computerized, they cannot adjust anything anymore

 

I run Shell V-Power 93 exclusively. It makes me feel better and as long as I can afford it I'll keep doing it. It might not make a "huge" difference but it isn't going to hurt the engine.

Didn't read the entire thread so if this was posted before I apologize in advance.

http://www.youtube.com/watch?v=WTaBngvsPrc​

 

He probably lives somewhere like I do, vancouver BC. I typically go to chevron. The lower octanes are grouped togethor, that states up to 10 ethanol right beside the handle. Then 91 is by itself and ses no ethanol.

I ran the first 14,000km of my truck on 87 with 10% ethanol. After reading this thread I`m goona switch to the 91 ethanol free and see what it does.

 

Just make sure you really do have ethanol free 91 before you pay for it. The octane rating and ethanol content have zero to do with each other.

 

Ethanol does bad things to gas lines on older cars....and now they are trying to up the percentage from 10% to 15%...

If you were to run on pure ethanol, you gas mileage would plummet...so, now they are going to force 15% stuff on us, meaning LESS mpg...somehow this all doesn't make any sense except for corn farmers...

Bleh..

I run the 87 stuff most of the time, higher octane at higher elevations though...

 

+1 this is why in FL have Non-Ethanol stations down here for boats. It reeks havoc on boats down here.

 

93 is the only gas I've ever put in it. Dont know how other octanes perform.

 

89 is all I use in any of my vehicles. Happy medium between cheap and premium.

 

Page 395 of 2006 owner's manual:
http://www.toyota.com/t3Portal/document/om/OM35858U/xhtml/OM35858U_OM0019.html?locale=en

 

My truck pings on accel when air conditioning is on when running 87 or 89, went to 91, all better.....will always run 91 in this truck now......

 

Just FYI.

Page 74 of the 2010 US Owners manual states:

Fuel types:
Use unleaded gasoline. (Octane Rating 87 [Research Octane Number 91] or
higher)

Page 483:

Toyota allows the use of oxygenate blended gasoline where the
oxygenate content is up to 10% ethanol or 15% MTBE.

 

That is odd and I wonder how many here have overlooked your post. I just checked my 09's manual and in the specifications part it just says "87 or higher" and then later on it has a section about fuel but just says not to use anything with higher than 10% ethanol. No where that I can find does it say "for better performance use 91".

I wonder when that was changed? EDIT: answered my own question, changed in 2007, see p. 402 : http://www.toyota.com/t3Portal/document/om/OM35869U/pdf/07omsour/2007/07tacoma/8.pdf

As far as I can tell, it's been the same 1GR engine since 05, right? Did toyota make any changes to the engine at all, and if not I wonder why they stopped recommending the premium fuel for better performance?

http://www.toyota.com/t3Portal/document/om/OM35883U/pdf/sec_6-1.pdf
p.479 in the 09 manual

 

I posted results 6 months ago here but now an update.
I have carefully logged over 50 fillups and find that 93 octane gives me between .5 and 1.0 mpg better mileage than 87 octane. But, the cost difference doesnt make it worth it.
However, I have noticed knock a few times using 87. Typically when the engine has not quite warmed up, at low speed and low rpm, which puts the engine under load.

 

87 on a v6 with no issues.

 

Changing octane will do nothing but hurt your performance unless you go to a higher compression engine where (like one of the first posts said) it burns slower so the higher compression engine will not detonate ( where the fuel ignites to soon because of the compression, also known as the diesel affect) as for a dyno showing more hp with higher octane, you don't know much about engines. If the temperature drops 1 degree or the humidity drops 1% or the barometric pressure goes up one point between pulls, THE HORSEPOWER WILL GO UP, there's you explanation for that
Wanna know my source of this info?
I'm a NASCAR technical institute graduate with a 4.0 and two "crew chief" awards in high performance engines

 

So nobody has any answer as to why the manual used to recommend high octane gas for better performance?

 

At what point during the stroke is the piston in the cylinder programmed to be when the fuel is ignited on 87 octane? What does the program change when engine is operating on 93?

Do the changes the programming makes change the effective compression ratio?