Premium Gas and Better MPG

Is this exchange about the HP increase using premium fuel?

 

Yes (I think, I tend to bounce back and forth in the forum so I may be totally lost by now).

 

"The recommended level is usually octane 87. Some car models have high-compression engines, which are designed to utilize octane levels of 89, 91 or higher. Ordinarily, your vehicle won’t benefit from using an octane higher than your owner's manual recommends. But if your engine knocks or pings at the recommended octane level, you may need a higher octane gasoline to prevent knocking."

In short, assuming the vehicle is not worn out or has some other mechanical problem, premium will not benefit a vehicle rated for 87. The factory settings in the vehicles computer is pre-set for a certain octane fuel. If set for 87, then anything higher does nothing but drain your wallet.

Another link explaining the same
http://blog.hemmings.com/index.php/...the-fiction-behind-those-higher-priced-fuels/

In summary, most modern vehicles do not require higher octane fuels, unless specifically expressed in your owner’s manual (read carefully, because there is a difference between higher octane being “recommended” and “required” in the manual). There are a few high-performance engines that were built with higher compression ratings or use higher RPM camshafts where 91 octane may be needed, but your average Subaru or V-6 Explorer will see no noticeable benefit from using the more expensive blends.

 

I know about octane, I just was commenting on the vast amount of idiot proofing that Exxon link has going for it.

No real explaining at all, just really a basic, ultra simple statement.

 

No it doesn't.

I know the difference between RON and AKI.

Here's the page from a 2006 Manual:



...also, on the TRD webpage for the supercharger it says: Produces 304 hp @ 5,400 rpm and 334 lb.-ft. torque @ 3,600 rpm (from 239 hp @ 5200 rpm; 278 lb.-ft. @ 3700 rpm. http://www.toyotaracing.com/trd/par...tegories=Performance Engine&subcategories=all

I'd assume that's where folks are coming up with the premium fuel figure.

 

Good Question. I just double-checked and it was there until 2007. In that manual it mentions nothing about fuel with higher than 87 octane. Same with my 2011.

I suspect it was marketing since it was causing 3rd party websites to list the V6 Tacomas as "premium fuel recommended"

 

@js312

You are correct about that "improved performance" section regarding 91 octane (research octane 96). I just looked in my 2006 manual and it's there -- I just didn't read down far enough.

Maybe they didn't consider that there was enough "improved performance" to justify including the note in later manuals. They also may have been told by their statisticians that three horsepower was not significant in the testing. Or, there may have been an emissions or other engine change that negated the increase.

 

Yes & No

I've seen increased MPG in some of the vehicles I've run Premium gas into - not necessarily the Tacoma.

However - even though its increasing your gas mileage, the COST PER MILE is the same as buying the cheap gas - so there's no real benefit in cost savings as you'd assume.

After you figure out the MPG....figure out the COST PER MILE.

If you're feeling a performance gain - then that's a personal preference to keep using it. But.... gas mileage increases are minimal and not necessarily cost effective.

 

When I took a long drive in my Tacoma after going to pick it up I thought I noticed a power increase with 91 but I'm not really sure. 88 octane feels about the same and it is slightly more sluggish with 87. I haven't really owned it long enough to try the different grades for longer periods of time. It's got 88 octane non-deathanol in it right now. It has been said that deathanol lowers mpg so I'll find out.

 

Haven't looked into the details. Just know that when I went from CA to WA and fueled up in your state, my MPG jumped an extra 50%.

 

we have 93 octane here.

i remember one time back when i had a mitsubishi evo ix that it required 91 or higher. there was a couple of weeks where 93 octane was out at every gas station in town.

so i was forced to put 87 octane in it. it ran ok but it was low on power and knocked a tad going up a steep hill or something. so i went to this place that sells off road racing fuel that is like 106 octane or something and put about 1/4 tank of that in to balance it out. that car ran great and had awesome power when i did that. it was a very noticeable difference in power.

 

That's because it wasn't knocking anymore, which robs an engine of power. If a truck is engineered for 87 octane gas it really doesn't do all that much good to use 91 octane in it. However, as I might have mentioned, if your 87 octane contains ethanol and your 91 octane doesn't then you might see better mileage as the "regular" gas contains less energy per gallon. If both 87 and 97 do or do not contain ethanol they will have the same energy content per gallon. Higher octane doesn't significantly increase the energy density of gasoline. However, a gallon of E10 has only 96.7% the energy of a gallon of pure gasoline.

 

Tested it well on a recent trip to Arizona and back... premium one way, regular coming back... I actually got the best mileage with the regular tank! 19-20 mpg range. V-6 automatic, driving speed limit (65-75), empty bed.

I found that there was near no difference between using the two, except you pay more for premium and the mileage is the same or slightly worse. I posted all the results here a couple months ago.

None of the gas was labeled as ethanol free, and actually may contain up to 10% ethanol was on all the pumps, even Arizona.

I do believe ethanol free gasoline will give better mileage. I use it in Mexico (Pemex), but cannot do accurate gas mileages on it typically because I am heavily loaded for camping, use 4WD on some of the tanks, or cannot trust the pumps to be 100% accurate at most stations down there (to get a true figure for fuel put in the tank).

 

Supposedly, in America pump accuracy is tightly regulated. However, I once filled up at a station in Chicago and was interested to find that My 1987 Toyota truck's tank suddenly was capable of holding well over 25 gallons of gas.

 

LOL!!!

There is a running joke in Mexico how magical it is for a Pemex pump to be able to put 22 liters into a 19 liter (5 gallon) gas can!!!

There are honest stations. The station in El Rosario is one, and handy because it is about 230 miles from the border (San Diego) and about the same distance to the next open station going south.

Also, go where the locals go in bigger towns with several stations... and use the pump they use... not the one the gringos in their big motorhomes can more easily drive up to!

 

I believe there is something else to it, possibly the ethanol content. I filled up with premium from another station and my truck went back to running like crap again. This leads me to believe that it is not the octane but rather the quality of the gas. Moreover I believe that the industry doesn't regulate it as strictly as once thought. I think the levels of ethanol range depending on the vendor and time of year. I just read an interesting article which I will post below.


Heres the link; copy and paste


http://blogs.cars.com/kickingtires/...r-mileage-may-vary-for-the-worse-ethanol.html

 

The fun thing about wiki is you can back your bs with bs citations. Im pretty sure god himself chimes in from time to time. Its entertaining and does contain real info, but i consider most of it to be my brothers friends uncle once met a guy type info.

In the end 3 hp doesnt matter in the least. A 10 billion hp engine is only making 30hp 99% of the time, same as a 100hp engine under the same conditions.

A modern engine will retard itself when it detects knock. If your engine doesnt knock on low octane it wont. Thats pretty much the end of how octane affects your engine.

 

I agree with chris4x4 and have experienced similar results. My 2TR responds better to 91 (throttle response, part throttle and WOT driving, and pulls harder from a dead stop). Especially during Socals hot summer days.
And not all gas stations are created equal... lots of variables in the quality, freshness and storage of fuel. There are only a few stations in my area that I frequent.