Premium Unleaded Fuel Test, Unscientific

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I curiously read some comments about running higher-octane fuel in the T4R and getting better performance and/or mileage. I have been running regular unleaded only, and have been average about 17+ MPG (I'm getting about 350 out of a tank, based on the trip odometer, which I reset at each fill up, and I typically put just over 20 gallons in per fill up). This has been pretty consistent for a year, unless I do a lot of towing.

So I tried, ONE tank of premium to see how it went. I actually got less miles, and believe it was a typical driving week or so. I did feel like under acceleration the engine sounded and felt stronger, but not dramatically.

So very unscientifically, I don't think there was much "reward" for the extra $4 a tank (20 * $0.20/gallon).

My questions would be (1engineer?):

1. would I need to run several tanks before the engine management "learned" how to run the engine (this is what the BMKW dealer always try to tell me happens in BMWs)

2. is there a way to reset the "adaptations" (the BMW term)

3. if you just want a little more grunt sometimes, like a long towing trip, is there an additive that anyone truly believes improves HP (don't care so much about MPG)

4. is there a spec sheet or tech specs from Toyo that specifies what we get from the 5th gen with different fuels?

Thanks...
b

 

[Biggcrisp]

I have an older relative that only uses premium and adds Lucas gas treatment. My thoughts are:

He can't take his money with him after death.
If it makes him feel better then what do I care.

 

[kiloil]

You can always strap it down to a dyno and do before after dynos. I be surprised to see anything over 5HP difference. Different in turbo vehicles, and high compression vehicles.

 

[harper7]

I curiously read some comments about running higher-octane fuel in the T4R and getting better performance and/or mileage. I have been running regular unleaded only, and have been average about 17+ MPG (I'm getting about 350 out of a tank, based on the trip odometer, which I reset at each fill up, and I typically put just over 20 gallons in per fill up). This has been pretty consistent for a year, unless I do a lot of towing.

So I tried, ONE tank of premium to see how it went. I actually got less miles, and believe it was a typical driving week or so. I did feel like under acceleration the engine sounded and felt stronger, but not dramatically.

So very unscientifically, I don't think there was much "reward" for the extra $4 a tank (20 * $0.20/gallon).

My questions would be (1engineer?):

1. would I need to run several tanks before the engine management "learned" how to run the engine (this is what the BMKW dealer always try to tell me happens in BMWs)

2. is there a way to reset the "adaptations" (the BMW term)

3. if you just want a little more grunt sometimes, like a long towing trip, is there an additive that anyone truly believes improves HP (don't care so much about MPG)

4. is there a spec sheet or tech specs from Toyo that specifies what we get from the 5th gen with different fuels?

Thanks...
b

Supposedly they have adaptive ignition timing that adjust the timing according to the feedback from the knock sensors.Running high octane fuel would be less prone to detonation and advance the timing,thus making it more efficient but it takes awhile for it to "learn" the new gas. Wether that increase in efficiency offsets the higher price of premium is the question. I'll be required to run premium next summer so I'll wait til then!

Here is a good read on it where I was enlightened ,thanks to JB...... Welcome to Land Cruiser Owners On Line

 

[1engineer]

I curiously read some comments about running higher-octane fuel in the T4R and getting better performance and/or mileage. I have been running regular unleaded only, and have been average about 17+ MPG (I'm getting about 350 out of a tank, based on the trip odometer, which I reset at each fill up, and I typically put just over 20 gallons in per fill up). This has been pretty consistent for a year, unless I do a lot of towing.

So I tried, ONE tank of premium to see how it went. I actually got less miles, and believe it was a typical driving week or so. I did feel like under acceleration the engine sounded and felt stronger, but not dramatically.

So very unscientifically, I don't think there was much "reward" for the extra $4 a tank (20 * $0.20/gallon).

My questions would be (1engineer?):

1. would I need to run several tanks before the engine management "learned" how to run the engine (this is what the BMKW dealer always try to tell me happens in BMWs)

2. is there a way to reset the "adaptations" (the BMW term)

3. if you just want a little more grunt sometimes, like a long towing trip, is there an additive that anyone truly believes improves HP (don't care so much about MPG)

4. is there a spec sheet or tech specs from Toyo that specifies what we get from the 5th gen with different fuels?

Thanks...
b

First of all there is little difference in energy content of regular versus premium gasoline. They both contain about 111,400 British Thermal Units of energy per gallon. Remember this is ALL the energy available per gallon to power your 4Runner. Vehicles of course don't use all of this potential and the additives in premium fuel do not unlock any more potential energy and sometimes decrease this potential. Hopefully there are a few chemical engineers here that could expound on this but I have not heard of any posting here. If there is no potential energy difference then performance gained would only be by the "additives" used to increase octane rating which in most cases is ethanol, which knocks the energy content down a small amount. Now, armed with this little tidbit of information:

1. It will take some time for your 4Runner to "learn" what fuel you are using. Your engine has the ability though to advance timing to compensate for fuel used. How long? I do not know. I would hazard a guess and say within less than a tank it will adjust accordingly.

2. Disconnect you battery for several minutes. This will reset previous learned behaviors and you can start from scratch.

3. If you use "real" gasoline that is not mixed with ethanol then you will see a small performance gain and better efficiency, or 1-2 mpg better with our 4Runners. There are quite a few stations that still sell this fuel but it has been proven that the higher cost of the fuel up front negates any real savings over the long run.

4. There is no spec sheet that I know of that lists performance using different grades of fuel. Unfortunately different manufacturers use different additives and if you go back to my original energy content statement there is no additional energy available just because the octane rating is higher. Octane ratings only show a fuel's ability to withstand higher compression - NOT energy content of fuel. This is the most common misunderstanding of average consumers and the oil companies will do little to clarify that definition. Octane ratings measure a gasoline's ability to resist engine knock — a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. So if your truck is not knocking (which our vehicles won't because of initial design parameters and compression levels) then use the lower octane and save money. Hope this helps and don't believe the hype or a dealership.

 

[philsey]

.... I'll be required to run premium next summer so I'll wait til then!

All y'all catch this?

:trophy:

 

[Greg_Canada]

First of all there is little difference in energy content of regular versus premium gasoline. They both contain about 111,400 British Thermal Units of energy per gallon. Remember this is ALL the energy available per gallon to power your 4Runner. Vehicles of course don't use all of this potential and the additives in premium fuel do not unlock any more potential energy and sometimes decrease this potential. Hopefully there are a few chemical engineers here that could expound on this but I have not heard of any posting here. If there is no potential energy difference then performance gained would only be by the "additives" used to increase octane rating which in most cases is ethanol, which knocks the energy content down a small amount. Now, armed with this little tidbit of information:

1. It will take some time for your 4Runner to "learn" what fuel you are using. Your engine has the ability though to advance timing to compensate for fuel used. How long? I do not know. I would hazard a guess and say within less than a tank it will adjust accordingly.

2. Disconnect you battery for several minutes. This will reset previous learned behaviors and you can start from scratch.

3. If you use "real" gasoline that is not mixed with ethanol then you will see a small performance gain and better efficiency, or 1-2 mpg better with our 4Runners. There are quite a few stations that still sell this fuel but it has been proven that the higher cost of the fuel up front negates any real savings over the long run.

Yep, there is no more "Energy" in higher octane fuel... all it does is let the ECU run more timing which gives you a bit more power and mileage.... fully compensated it's about 10-15hp difference, and maybe .5-1mpg max.

The "real" non-ethanol gas will not give you any more power (same octane = same power) but will give you better mileage as there is no ethanol. However it will give a more significant MPG difference than 87 to 91 10% ethanol fuel.

Agreed on your points...

 

[azn-sensation]

All y'all catch this?

:trophy:

Yup! S/C I suppose?:first:

 

[Randyman...]

I'll be required to run premium next summer so I'll wait til then!

All y'all catch this?

:trophy:

Yup! S/C I suppose?:first:

lolz...

Saving up over here, too :hello:

 

[Squelch]

Oooooo... must... resist... urge...



So... harper, TRD or URD or other?

All y'all catch this?

:trophy:

 

[harper7]

Oooooo... must... resist... urge...



So... harper, TRD or URD or other?

ummm.....Let's just say, It looks like I'll be driving back east and then to Colorado this summer as I got the month of July off for vacation again and premium gas may be required.:madgrin:

 

[Squelch]

ummm.....Let's just say, It looks like I'll be driving back east and then to Colorado this summer as I got the month of July off for vacation again and premium gas may be required.:madgrin:

Looking forward to the trip report! :madgrin:

 

[[email protected]]

My do more testing...

Thanks for the input everyone. Right now, premium in Atlanta is a good 30 cents/gallon than regular. So over a year, I guess we're talking a few hundred bucks, which is nice. Both my other cars use premium only (BMW, Porsche), so I already buy a fair amount of Premium.

The cost was only a bonus, I'm much more interested in a performance boost when I'm doing a lot of towing (boat) in the summer. Maybe I'll run a few more tanks in the spring when I start heading to the lake. But for now, it just seems to run fine on regular.

Thanks...

 

[Mwald3]

Supposedly they have adaptive ignition timing that adjust the timing according to the feedback from the knock sensors.Running high octane fuel would be less prone to detonation and advance the timing,thus making it more efficient but it takes awhile for it to "learn" the new gas. Wether that increase in efficiency offsets the higher price of premium is the question. I'll be required to run premium next summer so I'll wait til then!

Here is a good read on it where I was enlightened ,thanks to JB...... Welcome to Land Cruiser Owners On Line

Great article!!

 

[itr1275]

So I tried, ONE tank of premium to see how it went. I actually got less miles, and believe it was a typical driving week or so. I did feel like under acceleration the engine sounded and felt stronger, but not dramatically.

So very unscientifically, I don't think there was much "reward" for the extra $4 a tank (20 * $0.20/gallon).

It's an old post but I figured I would chime in.

In simplistic terms, think of Octane as the resistance to ignition. The higher the octane the more resistance. You would think this is bad, unless you have high a compression motor or advance your timing beyond spec.

The knock is a pre-detonation. With a high compression motor and low octane fuel the fuel will ignite sooner, because of the compression, than needed and that's the knock you hear.

Similarly if you advance your timing, you ignite the fuel sooner and pre-detonate. In the old days we used to advance our timing to get a few more HP out of our tiny little motors. Then the smog laws came in and they started checking that stuff. :cry2:

 

[itr1275]

So I tried, ONE tank of premium to see how it went. I actually got less miles, and believe it was a typical driving week or so. I did feel like under acceleration the engine sounded and felt stronger, but not dramatically.

So very unscientifically, I don't think there was much "reward" for the extra $4 a tank (20 * $0.20/gallon).

It's an old post but I figured I would chime in.

In simplistic terms, think of octane as the resistance to ignition. The higher the octane the more resistance. You would think this is bad, unless you have high a compression motor or advance your timing beyond spec.

The knock is a pre-detonation. With a high compression motor and low octane fuel the fuel will ignite sooner, because of the compression, than needed and that's the knock you hear.

Similarly if you advance your timing, you ignite the fuel sooner and pre-detonate. In the old days we used to advance our timing to get a few more HP out of our tiny little motors. Then the smog laws came in and they started checking that stuff. :cry2:

Running higher octane in your regular motor does nothing except waste your money.

 

[1jzgte]

It's an old post but I figured I would chime in.

In simplistic terms, think of octane as the resistance to ignition. The higher the octane the more resistance. You would think this is bad, unless you have high a compression motor or advance your timing beyond spec.

The knock is a pre-detonation. With a high compression motor and low octane fuel the fuel will ignite sooner, because of the compression, than needed and that's the knock you hear.

Similarly if you advance your timing, you ignite the fuel sooner and pre-detonate. In the old days we used to advance our timing to get a few more HP out of our tiny little motors. Then the smog laws came in and they started checking that stuff. :cry2:

Running higher octane in your regular motor does nothing except waste your money.

I'll take a stab at this.

The 1gr-fe is capable of making 15 more hp and 5lbs/ft more on 91 octane all thanks to advanced timing. But its also been confirmed it takes many tanks of 91 octane before the ECU allows timing to advance. This is mainly to flush the lower octane out before it allows the changes in timing.

I've never tried higher octane. Perhaps when gas takes a dip past the $2.00 mark again just for fun.

https://en.wikipedia.org/wiki/Toyota_GR_engine