Regular Unleaded or Premium Unleaded? (1 Viewer)

[NMuzj100]

Ok, Bad example. I finally get the one-finger (or is that two ?) salute on this board. But I doubt you see many Branded trucks on the road anyway. Does that mean I get "Techron" in my Texaco ?

How about a BP truck loading fuel at Texaco. Here in ABQ all the gas sold is refined at a Giant (local Co) refinery and resold by the Majors and independents.

Gas is a featureless commodity and should be purchased on price so long as there are no obvious worries that it has been spoiled since refining.

 

[hank14]

For clarification- where exactly is the fuel filter? I though it was in the gas tank, attached to the fuel pump, which is accessed only by remiving the double wide second row seat and the access cover under the carpet/floor.

 

[Kalen]

The fuel filter is a black canister that's bolted outside of the engine on the driver side of the engine compartment.

I was told that they do not need replacement by the Toyota parts counter, but a Toyota mechanic says he didn't believe it.

It's not that expensive and easy to access, so I replace mine at 115K mile during a major maintenance anyway.

It could just be psychological, but I thought the LC ran smoother afterwards. (Then again, I had all my belts, water pump, spark plugs, air filter, oil filter...ect changed at the same time.)

 

[hank14]

Thanks. I guess I was thinking of the fuel pump only, which I considered replacing when I was having some low idle problems. It turned out to be the throttle body needed cleaning- an easy fix. I'm going to order a new fuel filter. It's one of the many things I have had difficulty finding in my factory service manuals. To me, they are as clear as mud.

 

[Pitbull]

The fuel filter is a black canister that's bolted outside of the engine on the driver side of the engine compartment.

I was told that they do not need replacement by the Toyota parts counter, but a Toyota mechanic says he didn't believe it.

It's not that expensive and easy to access, so I replace mine at 115K mile during a major maintenance anyway.

It could just be psychological, but I thought the LC ran smoother afterwards. (Then again, I had all my belts, water pump, spark plugs, air filter, oil filter...ect changed at the same time.)

Replaced the fuel filter on my 80 at 100K miles and it didn't need it based on the condition of the old fuel filter. I would not waste my money again.

 

[Jim_Chow]

I had my fuel filter replaced at 125K...couldn't tell any difference vs. before/after. Just replace it for peace of mind. At least you'll know your injectors are less likely to get clogged.

 

[psfpilot]

www.toptiergas.com

For information about why some brands of gasoline are theoretically better than others.

 

[tabraha]

15,000 miles per year, 15mpg, .$20 more per gallon = $200 a year more AT MOST.

Now lets assume you lose 1 little mpg for going with the dirt. Without a doubt you will, if not immediately then over time.

At 15,000 miles per year, and a change grom 15 to 14 mpg, you would use 71 more gallons. At $2.20 a gallon, that's $156.20 in extra gas. So if you only loose 1mpg, you would save a whopping $43.80 over the course of a year.

Also consider if you put the engine under load, as in hauling or pulling steep grades your gonna loose more than 1mpg as the engine will want more bang from the gas but won't be able to get as much. It will have to work hard for longer because the ECU will be running in a watered down mode.

Our LX routinely gets 15-17mpg, with most of those being 17mpg. I have had to put regular in it before and when I hit the hills I knew it. I run the same stretch of interstate on cruise control at 68mph with the same 6 adults every weekend during football season. I get 16-17mpg and the vehicle pulls every hill without downshifting. With the regular gas, same people, cruise on 68mph, it downshifted (screaming) on at least a third of those hills, and my mpg was around 13mpg. All that for less than $50 savings annually? No thanks.

edit: with my mileage dropping that significantly, it actually cost me more money to run poorer!

 

[rzpapp]

I used to alternate 91 and 87... but I have noticed that with 91 I get about 1mpg better gas mileage over all and almost 2mpg better on long road trips vs using 87. And with the price of gas in the $2-$3 range and the price difference between 91 and 87 remaining around ~20cents... Its actually cheaper to use 91

 

[theRash]

I run premium in my 98 because that is what it said to use. Its a difference of 5-7 dollars (approx. 20 cent diff from 85 to 91 octane * 24 gallons or so) each fillup depending upon gas prices in your area. I just eat the ~6 bucks and move on.

 

[calamaridog]

There are two filters, one in the tank and one in the engine compartment. If you ever had to drop the tank you might as well replace the filter also.

 

[Pskhaat]

I'm no petroleum engineer but am an engineer, went to a petrol/mining university, and grew up in an oil family. I still can't believe reports that high-test gets you 1-2 mpg better. It seems very strange. The lower the `octane' level, the more quickly (and potentially thoroughly) the fuel will burn and thus marginally will extract higher energy from lower octane fuel which (if the engine is not knocking) should transform directly into increased mpg on low-test (especially on a constant-rpm highway drive).

Now I do agree that high-test is benenficial during towing, off-roading, low-altitude, hilly terrain, stop & go | city, and hot weather, and since I live in PHX, drive hills and mainly in the city my 100 will mostly see high-test. But on a long highway drive if the engine (ECU) is not having to retard itself on low-test you SHOULD get better mileage on it.

Same reason that high-altitude regions get 85 octane as their `regular' gasoline: you can get away with/need a higher rate-of-burn fuel with less oxygen content in the air (rather any given volume of air for an atmospheric pressure).

I guess I need to do some very serious empirical testing on the 2UZ-FE, but my 80 gets equal mpg on either high- or low-test over my 10 years with her in all sorts of conditions.

 

[tabraha]

Don't just look at the combustion dynamics though. Look at how many different ECU maps there are dependent upon what the advance, timing and quality of fuel will allow. If the world was flat I bet your theory on better milieage on low octane would hold true for every vehicle. I think that it depends on the engine too though. My Tacoma could gove a rat's a** if it has premium but my 100 sniffs it out quick. Maybe it's a condition inherent to my 100 and not other 100's but you gotta go with what works and on my 100 it's premium by a longshot. I keep a pretty close eye on the numbers, hell I'm the same knucklehead that keeps track of the cost to maintain my 100 even though it's at around $0.01/mile now. (You can never have too much info right?)

I'm no petroleum engineer but am an engineer, went to a petrol/mining university, and grew up in an oil family. I still can't believe reports that high-test gets you 1-2 mpg better. It seems very strange. The lower the `octane' level, the more quickly (and potentially thoroughly) the fuel will burn and thus marginally will extract higher energy from lower octane fuel which (if the engine is not knocking) should transform directly into increased mpg on low-test (especially on a constant-rpm highway drive).

Now I do agree that high-test is benenficial during towing, off-roading, low-altitude, hilly terrain, stop & go | city, and hot weather, and since I live in PHX, drive hills and mainly in the city my 100 will mostly see high-test. But on a long highway drive if the engine (ECU) is not having to retard itself on low-test you SHOULD get better mileage on it.

Same reason that high-altitude regions get 85 octane as their `regular' gasoline: you can get away with/need a higher rate-of-burn fuel with less oxygen content in the air (rather any given volume of air for an atmospheric pressure).

I guess I need to do some very serious empirical testing on the 2UZ-FE, but my 80 gets equal mpg on either high- or low-test over my 10 years with her in all sorts of conditions.

 

[rzpapp]

I'm no petroleum engineer but am an engineer, went to a petrol/mining university, and grew up in an oil family. I still can't believe reports that high-test gets you 1-2 mpg better. It seems very strange. The lower the `octane' level, the more quickly (and potentially thoroughly) the fuel will burn and thus marginally will extract higher energy from lower octane fuel which (if the engine is not knocking) should transform directly into increased mpg on low-test (especially on a constant-rpm highway drive).

The amount of fuel one uses has less to do with the chemical energy in the fuel then how the ECU reponds to preset air/Ox flow, and combustion. I belive the toyota V8 is designed for higher octane combustion but "works just fine" as in the ECU can compensate for a more volitale (and all be it higher energy... ie diesel fuel is even higher energy then gasoline) lower octane fuel... all be it with lower mpg

 

[Pskhaat]

It is common belief here I've read that the newer 2UZ-FE drops this requirements. The only thing (as I've stated in other threads) is that the 2UZ configuration must have been VERY prone to pre-ignition. Keeping the displacement the same, Toyota overbored and destroked the 2UZ. This in my book gives the ring-to-block mating more surface area if you will to possibly control this pre-detonation. I am utterly suprised that the torque/HP ratings to be so equal as this would generally decrease the torque and allow for higher RPMs. However, there must have been significant ECU changes during that time or those pistons in the latter-models could possibly be of more mass?

I wish Toyota would call them the 3UZ configuration then as the changes in my book are significant enough for a new block designation. The 2F for instance had the same bore and stroke through it's generation, the 3F was destroked. Following that no reason to continue to call it the 2UZ.

Anyway, I'm rambling and I'll stop

 

[tabraha]

However, there must have been significant ECU changes during that time or those pistons in the latter-models could possibly be of more mass?

It was the ECU that was changed primarily as I don't believe there was a piston change. Dean (DMX84) I believe explained the ECU changes quite nicely at one point possibly in one of the other premium vs regular threads. The thread topic has been around the block a few times so I can't really point to the exact post it was. It's in one of those other gas threads somewhere!!!

 

[Jim_Chow]

So which fuel will produce fewer hydrocarbons in the emissions?

 

[C-dog]

That's easy! Would you feed your kids or yourself McDonalds all the time your eat something healthy!

 

[DMX84]

So which fuel will produce fewer hydrocarbons in the emissions?

The lower octane will give you the lowest hydrocarbons.
The reason of doing this is that the octane rating of a fuel is it's resistance to burning, so the lower octane fuels are easier to fully combust.

 

[NMuzj100]

The lower octane will give you the lowest hydrocarbons.
The reason of doing this is that the octane rating of a fuel is it's resistance to burning, so the lower octane fuels are easier to fully combust.

So if the two fuels have the same amount of stored energy and the lower octane gas combusts more completely then shouldn't it be more fuel efficient? ceterus parabus.

?s for the forum. At altitude (ABQ is at about 5000ft) can the engine ever get any performance improvement from the premium fuel or will the limiting factor on performance always be our air density ? Why are octane levels lowered for higher altitudes. ?