Gas Talk

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Mar 13, 2003
North Front Range, CO
We have a oil expert with us, do we have a gas expert on hand?
On my trip I ran some gas with 10% ethanol, some were super (high octane) and some were 85(in Denver). The ethanol was cheaper in IA and NE. I use normal gas in WI most of the time.
I see Shell posts that their gas gets more MPG. Is there a different in brands of gas? What does higher octane do in the 1FZ?
Sorry that I've nothing to add directly to this post, but unleaded is $1.99 in Stamford, CT -- I LOVE THIS STUFF --

-- premium is $2.18!!
[quote author=erics_bruiser link=board=2;threadid=4623;start=msg34865#msg34865 date=1061837481]
-- premium is $2.18!!

Well, in PHX, Premium was about $3.99/gallon last week, even more in outlying areas! Count yourself lucky! Low-test gasoline after last week now ~$2.49/gallon.
[quote author=landtoy80 link=board=2;threadid=4623;start=msg34864#msg34864 date=1061837062]
What does higher octane do in the 1FZ?

I'm not a big believer in high-test fuel when not needed, but in my 1FZ-FE I do in fact note a better running engine on the premium unfortunately. With low-test I get a slight `knock;' more of a tick than a knock that is solved with premium fuel. But I'm one of very very few who have this problem in their FZJ80s. Normally, 85+ octane will be just fine for the 1FZ-FE.

And no, my timing is not advanced.
With the SC I have to run premium, so I'm glad I don't live in Phoenix :D.

The higher octane mostly serves to reduce detonation by reducing the spontaneous/unconrolled combustion of the fuel in the cylinder--this is what causes knock. It doesn't make the fuel any less "burnable" or flamable. But the premium fuels also happen to contain less contaminants, like sulpher. It probably doesn't make much difference to the LC, but I've read that in my Spyder, that engine can suffer longevity problems (i.e., worn rings) due to the higher sulpher content in regulary fuel (this was an actual Toyota engineer's report) as the sulphur is somewhat corrosive or abrasive when the engine is cold.

Around here, Getty used to use 10% EtOH in their gas during the winter months instead of adding MTBE. The EtOH served as the oxygenator instead. I don't know the pros and cons of doing this, but it certainly didn't smell as bad as that MTBE, and I never noticed any difference in quality. In both cases I think you get somewhat reduced milage since you're getting less "gas" per gallon--the EtOH or MTBE doesn't have the same "fuel" properties as does gasoline.

That's my story and I'm sticking to it.

MTBE does result in lower fuel mileage, it was well documented when it was foisted upon us in California.

I generally run 87 in the Cruiser, but have found that it seems to get a bit better miliage and power on 89. My Nissan Pathfinder is the same way. The wife's BMW wants 93 octane, problem is that we can only get 91 in the Republic of California.

On a related topic, has anyone actually tried the timing advance suggestion at cool80's? What was the result?

Cary--What's the timing advance thing? Wouldn't your ECU just adjust and bring the timing back to spec (within reason)?

Think I'll pass on the advance...with the SC, I think I'm already pushing things.


I agree, I would not go past baseline 3Deg BTDC with a blower. It's hard enough to control knock as is. I'm at 5000 ft and the best pump gas is 91 and it's got O2 enhancers in the winter. I fueled yesterday at $1.899 gal for premium at

I heard that Chevron puts more Tecron - or whatever they call the fuel injector cleaner- in the higher octane gas. Heard that about Mobil also.

I alternate between 89 and 91 octane, mainly to get the added cleaners. Or maybe I'm just a sucker for those cute little talking cars.


>> On a related topic, has anyone actually tried the timing advance suggestion <<
>> at cool80's? What was the result? <<

My engine is a stock '97 1FZ-FE with 125k miles. I'm running at 7 degrees BTDC (+4 over spec.) I did this change about a year ago and have continued to run regular fuel. I can't hear any pinging but C-Dan told me he heard mine pinging during a couple of WOT runs up a sand dune a few weeks ago. No degradation in engine cooling or anything else.

The result was a tiny improvement in mileage (.1 to .2 mpg) and a noticeable improvement in power.

I'm also running 7 degrees of advance, with a notable power increase, but no MPG increase. Over the 10 years I've had the Cruiser, I have noticed that premium gas gets me better MPG when running it hard - such as high speed freeway running or towing. So, I habitually run premium in anticipation of such use. I've never heard a single ping even with the crappiest gas, and I still have good hearing since I didn't ruin my ears with crappy music like the rest of you guys. Heh.

I run a can of Chevron's Techron (the concentrate, not the regular bottle) through it 1-2 times a year and have done this since new. My original plugs came out clean as a whistle at about 110k miles. I also use Chevron when possible, followed by national brands (Shell, Mobil, etc) and have probably put around 5 tanks of unbranded fuel in it in desperation over those 10 years. That stuff's terrible and often these unbranded/local stations get the dregs, or the old gas that won't pass muster with the majors, and they simply have a standing order out for the cheapest stuff that passes the lowest standards for gasoline. I once took a tour of a Chevron refinery, and befriended an engineer there I used to use for information on fuels and such. They routinely obtain samples of competitive fuels as well as these "second tier" gas stations. He says they'd find winter formulation in August, fuel formulated for other states, octane ratings all over the board (both high and low), contaminants, missing additives the gov't requires, etc. Enough to scare me. Kinda like touring a meat packing plant and becoming a vegetarian, I suppose....

Why do you lot call Petrol Gas. ???
Gas for B.B.Q.'s is a mixture of Butane and Propane, Where Automotive Gas is the Gas that comes off of Petrol during the Refining Process.

The main problems with Ethanol are: It breaks down the Rubber(Plastic) Fuel Lines. And Ethanol absorbs moisture, So Metal parts corode.

Petrol Octane ratings in Australia:
91 - Regular Unleaded.
95 - Premium Unleaded.
95 - L.R.P.(Lead Replacement Petrol).
96/97/98 - Specialty Petrol that is Exspensive for People whom are easily parted from their Money.
100 - Normal Japanese Petrol, Never been availible.

Toyota says for the 1FZ-FE in Australia to use 91 Octane.
I also use Chevron when possible, followed by national brands (Shell, Mobil, etc) and have probably put around 5 tanks of unbranded fuel in it in desperation over those 10 years.
In Australia Chevron is known as Caltex and they are the main supplier of Fuels to Independant Fuel Stations.

Caltex has the only Oil Rig in Australia that produces Fuels and Oils, Which is situated off South Australia. All other Oil Rigs only produce Natural Gas(The type that is plumbed into your house).

One Hundredth Post
Typical octane ratings in the US:

Regular unleaded: 85-87 octane
Mid grade: 89 octane
Premium grade: 91-93 octane

Many times, manufacturers "require" or specify higher octane fuel because these more expensive fuels also have better additive packages, detergents and are physically cleaner. This benefits the manufacturer by helping the fuel system components last longer with fewer problems, and by keeping cylinder deposits to a minimum - including injector tips, valves and spark plugs. If you're paying attention, it also helps you the owner if you're planning to keep the vehicle for a long time. It was the main reason Lexus vehicles specified premium when they first came out here in the US in '90 - greater reliability - as opposed to greater performance. I happened to be there when the decision was made. Quality vehicles built with tight tolerance quality fuel injectors for instance, might be susceptible to rough running if cheap fuel is routinely used and those tight tolerances quickly fill with deposits. Anyone care to make a bet that the BMWs, Mercedes, and Audis of the world also require premium fuel for the same reasons - not really for performance??

Anyone care to make a bet that the BMWs, Mercedes, and Audis of the world also require premium fuel for the same reasons - not really for performance??
In Germany their Normal Petrol is probably the equivelent of Premium Petrol. :flipoff2:

Just as in Japan 100 Octane is normal, Such as with the SR20DET in the Nissan Silvia - 95 Octane in Australia with 157kw and 100 Octane in Japan with 190kw. More Boost - Higher Octane resists detonation. :p
85-87 is good enough for me. The few times I have filled the tank with 91-93 octane the idle jumps at random and inoportune moments sometimes almost causing me to ram the poor old lady sitting in front of me at the light. Poor lady... I would crap myself if an ARB lurched at me in my rearview mirror. :D

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