Start switching to 87 octane gas.

[RickyCRX]

Then why does your 4Runner's owner's manual say to use premium if you are towing? Ding ding ding, for more power, because the engine can take advantage of it by advancing the timing and adjusting the injector pulse rates.

Trust me, a lot can be done with electronic tuning to net more power out of an engine, given a static compression ratio, just based on the octane of the fuel supplied to it. These days with electronic engine control systems, there is not an end-all-be-all answer.

Personally, I use regular in my 4Runner... The V8 makes plenty of power to not need premium. Once I start regularly transporting my CRX around on a trailer, I will re-evaluate my needs to run higher octane fuel, but even at that point I doubt I will need it, as there are not any big hills around here.

Ricky

As I have said, if you increase the compression, you must increase the octane. Any car designed to run on higher octane fuel needs it and you shouldn't run anything lower unless you are at a high altitude. I think we agree on that.

Now on a car that is designed to run on 87 octane, how could you possibly see any gains by increasing the octane rating? A gallon of 87 octane has the same stored energy that a gallon of 1000 octane does (Hypothetically speaking of course.) Where are you going to gain power?

Let me add this direct quote from the Chevron website:
Using gasoline with an antiknock rating higher than that required to prevent knock or to prevent spark retardation by the knock sensor will not improve a vehicle's performance.

 

[Spider5]

Your somewhat missing some information.

Compression is not increased to advance timing. While timing may have to be retarded to prevent preignition, advancing the timing does not yield increased performance.

Using your thinking can you explain why in the mountains you see lower octane fuels? You don't see 85 octane at sea level, and mid grade at sea level isn't 87 octane either. The thinner air makes less compression requiring a more volatile fuel.


It is great that you are keeping detailed records of miles driven, gallons, price, but I would be willing to bet you are missing some critical data and that is environmental data such as ambient air temperature and relative humidity. You see, it is a mixture and you like most people only keep records on the part you pay for. Air density is as important as the amount of fuel going in. Cars are not built to run at high altitudes so of course your not going to get the same performance in the thin air at 8000 feet as your would on a humid day in Fla.

It is easy to tell when your octane level is too low. The hard part that people understanding is that it can be just as bad if it is too high.

Contrary to popular belief, humidity actually makes the air density less not more.

 

[Pistonslap]

Then why does your 4Runner's owner's manual say to use premium if you are towing? Ding ding ding, for more power, because the engine can take advantage of it by advancing the timing and adjusting the injector pulse rates.

Trust me, a lot can be done with electronic tuning to net more power out of an engine, given a static compression ratio, just based on the octane of the fuel supplied to it. These days with electronic engine control systems, there is not an end-all-be-all answer.

Personally, I use regular in my 4Runner... The V8 makes plenty of power to not need premium. Once I start regularly transporting my CRX around on a trailer, I will re-evaluate my needs to run higher octane fuel, but even at that point I doubt I will need it, as there are not any big hills around here.

Ricky

You still don't get it. Octane is an anti-knock rating, NOT a performance rating. Adding octane is not going to give you extra performance during towing, it is going to stop the knocking. The reason that Toyota suggest that you use higher octane when towing is because towing adds stress, stress creates heat. What does higher octane do? Oh yeah, that is right, it prevents preignition. What contributes to preignition? Heat.

 

[Kanab]

You still don't get it. Octane is an anti-knock rating, NOT a performance rating. Adding octane is not going to give you extra performance during towing, it is going to stop the knocking. The reason that Toyota suggest that you use higher octane when towing is because towing adds stress, stress creates heat. What does higher octane do? Oh yeah, that is right, it prevents preignition. What contributes to preignition? Heat.

You are totally right on this!! I read somewhere that regular gas 87 octane even contains more energy then Premium gas 91 octane. Problem is that you can't control that energy at the compression levels that you can control the 91 because of the octane level. So it's not how much power you have its how you use your power.

 

[Iowa4Runner]

You still don't get it. Octane is an anti-knock rating, NOT a performance rating. Adding octane is not going to give you extra performance during towing, it is going to stop the knocking. The reason that Toyota suggest that you use higher octane when towing is because towing adds stress, stress creates heat. What does higher octane do? Oh yeah, that is right, it prevents preignition. What contributes to preignition? Heat.

You've only told part of the story. Why buy high octane fuel to stop the knocking when you can just buy the cheap stuff and let your engine retard the timing to take care of any knocking? Ricky has a valid point.

FWIW, octane is a fuel's resistance to detonation, not preignition. They are not the same thing.

 

[Koz]

There is good info here.

http://www.toyota-4runner.org/showthread.php?threadid=683

Koz

 

[Pistonslap]

You've only told part of the story. Why buy high octane fuel to stop the knocking when you can just buy the cheap stuff and let your engine retard the timing to take care of any knocking? Ricky has a valid point.

FWIW, octane is a fuel's resistance to detonation, not preignition. They are not the same thing.

Ok so argue over semantics. Where did I say they were the same? By definition they have nearly the same meaning and preignition actually is more specific to this issue. They are both nouns. With proper wording around them you could build a sentence that conveys the same meaning. Big deal.


Now to answer your question since you obviously did not read the previous posts or could simply not understand them. My point which you seem to be missing is that you only need to buy an octane high enough to PREVENENT preignition. Buying an octane higher than that will give you no benefit at all. Got it?

Let me explain it another way. Say your car runs on 87 octane perfectly well. You have absolutely no preignition. Your knock sensor detects nothing. Putting 100 octane in your tank will not yield a single bit of performance increase by the added octane.

I am not saying to buy the lowest octane you can find. If you go lower than what you need, you will suffer a loss of performance, but going higher than what you need will not result in a gain.

 

[Bluto]

... what you need ....

... is the question. There is no 'low octane' light on the dash for the average consumer.


Regular gas works.
Premium may or may not improve performance.
Premium can cause deposits if not needed?


I think everyone agrees, but explain it differently.

 

[rossmon1]

using 87 since march

You are right.

no ill effects so far, used 87 while towing and no knocking there either.
will try premium here 91 in a few days for a towing and see if there is any difference that i notice.

 

[Iowa4Runner]

Ok so argue over semantics. Where did I say they were the same? By definition they have nearly the same meaning and preignition actually is more specific to this issue. They are both nouns. With proper wording around them you could build a sentence that conveys the same meaning. Big deal.


Now to answer your question since you obviously did not read the previous posts or could simply not understand them. My point which you seem to be missing is that you only need to buy an octane high enough to PREVENENT preignition. Buying an octane higher than that will give you no benefit at all. Got it?

Let me explain it another way. Say your car runs on 87 octane perfectly well. You have absolutely no preignition. Your knock sensor detects nothing. Putting 100 octane in your tank will not yield a single bit of performance increase by the added octane.

I am not saying to buy the lowest octane you can find. If you go lower than what you need, you will suffer a loss of performance, but going higher than what you need will not result in a gain.

Instead of straightening out your mountain of pseudo-technical ramblings, false assumptions, and half answered questions, I'll make this ultra simple for you:

1. There is a correlation between ignition timing and engine performance.

2. There is a correlation between a fuel's resistance to DETONATION and a modern vehicle's ignition timing.

Therefore a higher octane fuel certainly can, and likely will (especially under towing conditions) improve engine performance.

So... Stop making ignorant blanket statements like "You are not going to feel a performance increase by using higher octane."

Got it?

 

[RickyCRX]

THANK YOU!!!

Instead of straightening out your mountain of pseudo-technical ramblings, false assumptions, and half answered questions, I'll make this ultra simple for you:

1. There is a correlation between ignition timing and engine performance.

2. There is a correlation between a fuel's resistance to DETONATION and a modern vehicle's ignition timing.

Therefore a higher octane fuel certainly can, and likely will (especially under towing conditions) improve engine performance.

So... Stop making ignorant blanket statements like "You are not going to feel a performance increase by using higher octane."

Got it?

 

[TechWrench]

I believe my 2005 manual states something like, for best performance use 91 octane or higher.

Am I right?

You are right. But the manual also states that you can run on 87.
The wrinkle is the "best performance" part. You will find the rig will run just fine on 87, and except for all out flogging or hard towing, you will probably not know the difference.

 

[Pistonslap]

Instead of straightening out your mountain of pseudo-technical ramblings, false assumptions, and half answered questions, I'll make this ultra simple for you:

1. There is a correlation between ignition timing and engine performance.

2. There is a correlation between a fuel's resistance to DETONATION and a modern vehicle's ignition timing.

Therefore a higher octane fuel certainly can, and likely will (especially under towing conditions) improve engine performance.

So... Stop making ignorant blanket statements like "You are not going to feel a performance increase by using higher octane."

Got it?

My apologies. I thought that I was talking to someone with at least some technical knowledge. You are right; I should have presented it at a 3rd grade level so that you two could understand. You should fill up with some 120 octane at your next fill up. I bet you will improve you 0-60 times by a good second and probably get better mileage at the same time.

Please humor me and show me my false truths or any unanswered questions. It is easy for you to sit there and make wild accusations, but you have not pointed out any facts. Actually I would like you to take it one step further. If anything that I have said is a 'false truth' along with pointing it out, I would appreciate you correcting it so that I can make sure that I will not spread bad information. Also, don't take a single sentence and not the support paragraph and take it out of context.

BTW, here is a total false truth in your statement:

"2. There is a correlation between a fuel's resistance to DETONATION and a modern vehicle's ignition timing."

There is no correlation between a fuel's resistance to PREIGNITION and timing. There is a correlation between timing and a knock sensor that detect preignition, but your engine has no idea of the fuels resistance until it runs through it.

Your next stement partially incorrect as well:
"Therefore a higher octane fuel certainly can, and likely will (especially under towing conditions) improve engine performance."

It can under certain conditions, but if your engine is designed for 87 octane and your knock snesor does not detect preignition you will get no benifit from anything higher. (as previously stated)

Is that simple enough?

 

[RickyCRX]

Maybe if you would just stop and think for a second, you will realize you just made yourself look like a complete idiot.

IF it states in the owner's manual to use 91 octane for better performance while towing, don't you think that MAYBE, JUST MAYBE our engines *ARE* designed for an octane rating higher than 87? And don't you think that MAYBE, JUST MAYBE our engine's knock sensors are sensitive enough that none of us hear any detonation and the computer pulls the timing back quickly enough so that our engines "appear" to be 'designed' to run on 87 octane??

You ARE correct in that if an engine is not designed for anything higher than 87, you are wasting money. This is true. But don't you think that our engines are likely designed to make use of higher octane fuel if the owner's manual recommends it for conditions that require more power? Many people have reported no ill effects of towing heavy loads with 87 octane in regards to engine temperatures, so that's likely not the reason. The reason is probably so that the engine can pull the load more easily without making the transmission do so much work of trying to find the right gear to be in for the load you're pulling.

The only REAL solution to all of this bickering is to get somebody with an OBD-II datalogger that can drive up a steep mountain grade at various RPMs with 87 octane fuel and see if the knock sensor is detecting any pinging and pulling back the timing. Or to log what the ignition timing is set to during these situations. Then do a back-to-back run with a full tank of premium to see how the numbers compare. This is the only way anybody is going to know the true answer to this. The rest is all guessing, no matter what kind of a background you may have.

Ricky

My apologies. I thought that I was talking to someone with at least some technical knowledge. You are right; I should have presented it at a 3rd grade level so that you two could understand. You should fill up with some 120 octane at your next fill up. I bet you will improve you 0-60 times by a good second and probably get better mileage at the same time.
...
<cut a bunch of garbage in here>
...
It can under certain conditions, but if your engine is designed for 87 octane and your knock snesor does not detect preignition you will get no benifit from anything higher. (as previously stated)

Is that simple enough?

 

[Iowa4Runner]

My apologies. I thought that I was talking to someone with at least some technical knowledge. You are right; I should have presented it at a 3rd grade level so that you two could understand. You should fill up with some 120 octane at your next fill up. I bet you will improve you 0-60 times by a good second and probably get better mileage at the same time.

Please humor me and show me my false truths or any unanswered questions. It is easy for you to sit there and make wild accusations, but you have not pointed out any facts. Actually I would like you to take it one step further. If anything that I have said is a 'false truth' along with pointing it out, I would appreciate you correcting it so that I can make sure that I will not spread bad information. Also, don't take a single sentence and not the support paragraph and take it out of context.

BTW, here is a total false truth in your statement:

"2. There is a correlation between a fuel's resistance to DETONATION and a modern vehicle's ignition timing."

There is no correlation between a fuel's resistance to PREIGNITION and timing. There is a correlation between timing and a knock sensor that detect preignition, but your engine has no idea of the fuels resistance until it runs through it.

Your next stement partially incorrect as well:
"Therefore a higher octane fuel certainly can, and likely will (especially under towing conditions) improve engine performance."

It can under certain conditions, but if your engine is designed for 87 octane and your knock snesor does not detect preignition you will get no benifit from anything higher. (as previously stated)

Is that simple enough?

I have very little time so at the moment I won't address everything you've commented on above.

"There is no correlation between a fuel's resistance to PREIGNITION and timing."

For that to be true, ignition timing can never be affected by the octane rating of the fuel you run. In other words, under identical operating conditions, ignition advance will be the same whether you have 50 or 150 octane gas in the tank. It that what you truly believe?

One more question: If you're towing a boat with a 4Runner and hear no knocking, are you certain that using higher octane fuel will not result in better engine performance?

Thanks...

 

[Koz]

:corn:

Koz

 

[Pistonslap]

I have very little time so at the moment I won't address everything you've commented on above.

"There is no correlation between a fuel's resistance to PREIGNITION and timing."

For that to be true, ignition timing can never be affected by the octane rating of the fuel you run. In other words, under identical operating conditions, ignition advance will be the same whether you have 50 or 150 octane gas in the tank. It that what you truly believe?

One more question: If you're towing a boat with a 4Runner and hear no knocking, are you certain that using higher octane fuel will not result in better engine performance?

Thanks...

Question #1: Yes and no. Of course this is hypothetical because 80 octane is about as low as it gets, but if your engine ran perfectly fine on a mythical 50 octane, you had no preignition in the conditions you were operating, then running 150 octane will not yield any improvement in performance. Now were the engine designed to run on 87 octane and you put 50 octane in and it would run on it, but pinged like crazy to a point that the timing was retarded to eliminate preignition , of course you would see an increase in performance a higher octane that does not cause preignition.

Question #2: This depends. Towing changes the operating conditions. Hearing the knocking may be impossible to detect. If it occurs and you can hear it, of course you would benefit by upping the octane. If by chance you had a scanner connected while towing and your knock sensor detected nothing, then you would not benefit at all by upping the octane.

The point I am trying to make is that correct octane is important. Anything lower will suffer from performance loss and increased engine wear, and anything higher will not increase performance and can lead to more problems down the road.

 

[Pistonslap]

Maybe if you would just stop and think for a second, you will realize you just made yourself look like a complete idiot.

IF it states in the owner's manual to use 91 octane for better performance while towing, don't you think that MAYBE, JUST MAYBE our engines *ARE* designed for an octane rating higher than 87? And don't you think that MAYBE, JUST MAYBE our engine's knock sensors are sensitive enough that none of us hear any detonation and the computer pulls the timing back quickly enough so that our engines "appear" to be 'designed' to run on 87 octane??

You ARE correct in that if an engine is not designed for anything higher than 87, you are wasting money. This is true. But don't you think that our engines are likely designed to make use of higher octane fuel if the owner's manual recommends it for conditions that require more power? Many people have reported no ill effects of towing heavy loads with 87 octane in regards to engine temperatures, so that's likely not the reason. The reason is probably so that the engine can pull the load more easily without making the transmission do so much work of trying to find the right gear to be in for the load you're pulling.

The only REAL solution to all of this bickering is to get somebody with an OBD-II datalogger that can drive up a steep mountain grade at various RPMs with 87 octane fuel and see if the knock sensor is detecting any pinging and pulling back the timing. Or to log what the ignition timing is set to during these situations. Then do a back-to-back run with a full tank of premium to see how the numbers compare. This is the only way anybody is going to know the true answer to this. The rest is all guessing, no matter what kind of a background you may have.

Ricky

Your right, I am an idiot for stating facts, but your hypothesis is cracking me up. "The reason is probably so that the engine can pull the load more easily without making the transmission do so much work of trying to find the right gear to be in for the load you're pulling." You should really head to Torrance and work for Toyota. They need you.

Try this because I would be afraid to see you try any test with any real machinery:

Get your big wheel out and ride around the block one time and see how much you sweat. Then tie a few big rocks to your big wheel and ride around the block and compare you sweat to your previous trip. I think you will see that you sweat more pulling the rocks. Mix your nomal amount of gatorade and drink to a point that you are not thirsty. Record the amount of liquid you consumed.
Now repeat the test again. This time double the amout of the powdered gatorade that you mix with water. Drink the high test gatorade as you did the first time. Record your results.
You should see that you drank the same amount even though you had twice the concentration.

Boys and Girls this is a scientific test. Please don't try this at home.

 

[RickyCRX]

Being a water-cooled engine, your cylinder head temperatures should not be appreciably higher while pulling a trailer as opposed to driving around town. The internal temperatures should be relatively static unless you are overheating, that's why there is a thermostat to keep things close to a 'normal operating range' at all times.

So in your case, regarding how much you sweat when doing x vs. y amount of work doesn't mean crap in regards to fuel octanes. The radiator is where the heat is dissipated. If it cooled by the same means as a human, your radiator would sweat more than just driving around town at 40mph, big deal.

If you want to make silly analogies, at least compare apples to apples, not apples to oranges.

As I said before; YOU HAVE NO IDEA IF THE KNOCK SENSOR IS PULLING BACK TIMING WITH 87 OCTANE UNDER **ANY** CIRCUMSTANCES; TOWING OR NOT!

Until you can prove to me that 87 octane in a 4Runner does not engage the knock sensor, then running higher pump octanes WILL result in improved performance. Nobody has proven to me that the 4Runner engine is not 'designed' to operate on something higher. Yes, it runs on 87, but it may be optimized for higher octane.

I am completely agreeing with you on the 'if your engine isn't pinging and the knock sensor isn't pulling back timing then you don't need higher octane'.... but you can't tell me that the 4Runner won't benefit from higher octane until you can prove to me that the knock sensor isn't pulling back timing with fuel rated at less than 91 octane.

Ricky

Your right, I am an idiot for stating facts, but your hypothesis is cracking me up. "The reason is probably so that the engine can pull the load more easily without making the transmission do so much work of trying to find the right gear to be in for the load you're pulling." You should really head to Torrance and work for Toyota. They need you.

Try this because I would be afraid to see you try any test with any real machinery:

Get your big wheel out and ride around the block one time and see how much you sweat. Then tie a few big rocks to your big wheel and ride around the block and compare you sweat to your previous trip. I think you will see that you sweat more pulling the rocks. Mix your nomal amount of gatorade and drink to a point that you are not thirsty. Record the amount of liquid you consumed.
Now repeat the test again. This time double the amout of the powdered gatorade that you mix with water. Drink the high test gatorade as you did the first time. Record your results.
You should see that you drank the same amount even though you had twice the concentration.

Boys and Girls this is a scientific test. Please don't try this at home.

 

[Pistonslap]

Being a water-cooled engine, your cylinder head temperatures should not be appreciably higher while pulling a trailer as opposed to driving around town. The internal temperatures should be relatively static unless you are overheating, that's why there is a thermostat to keep things close to a 'normal operating range' at all times.

So in your case, regarding how much you sweat when doing x vs. y amount of work doesn't mean crap in regards to fuel octanes. The radiator is where the heat is dissipated. If it cooled by the same means as a human, your radiator would sweat more than just driving around town at 40mph, big deal.

If you want to make silly analogies, at least compare apples to apples, not apples to oranges.

As I said before; YOU HAVE NO IDEA IF THE KNOCK SENSOR IS PULLING BACK TIMING WITH 87 OCTANE UNDER **ANY** CIRCUMSTANCES; TOWING OR NOT!

Until you can prove to me that 87 octane in a 4Runner does not engage the knock sensor, then running higher pump octanes WILL result in improved performance. Nobody has proven to me that the 4Runner engine is not 'designed' to operate on something higher. Yes, it runs on 87, but it may be optimized for higher octane.

I am completely agreeing with you on the 'if your engine isn't pinging and the knock sensor isn't pulling back timing then you don't need higher octane'.... but you can't tell me that the 4Runner won't benefit from higher octane until you can prove to me that the knock sensor isn't pulling back timing with fuel rated at less than 91 octane.

Ricky

The anology was meant to be a joke, leave your big wheel in the garage.