Longevity of A Vehicle...

[thegolfer18]

What I realize is that I should have been more specific. Modern engines with high CR are capable of running 87 and 91-93 due to their advanced engine management systems. The issue here is that with the gas prices as high as they are companies are now saying 87 or higher in their manuals. My Lexus says 87 can be used in the car, but for maximum performance 91 or higher is recommended. I have already stated all of this. I am not sure why this does not pass some of you knuckle heads. There are many cars out there with high CR, that will benefit from higher octane. And as for the "racing fuel" a car with a tune can run a more aggressive timing providing slight increase in performance. Hell with with just a modern ECU it will do this.

I don't think anyone is disagreeing with that, there's just no advantage to using higher octane than your engine recommends. If your engine recommends 91 for maximum performance but it also says 87 is fine to use, then use whichever one you want whether for better performance or cheaper gas. However, if it recommends 87 only and doesn't have an ECU that improves performance with higher octane, you will see no difference.

[B3sat16v]

Here is one possible scenario where using premium could prolong the life of your car : Older cars not meant to run ethanol could actually benefit from running on premium that has less or no ethanol in it.

What? All fuels (Gasolines) currently sold in the USA for the most part is E10. You can find some gas stations that might still sell pure gasoline, but they are rare to come across.

[B3sat16v]

I don't think anyone is disagreeing with that, there's just no advantage to using higher octane than your engine recommends. If your engine recommends 91 for maximum performance but it also says 87 is fine to use, then use whichever one you want whether for better performance or cheaper gas. However, if it recommends 87 only and doesn't have an ECU that improves performance with higher octane, you will see no difference.

Ford likes to do this a lot, but their ECU will actually account for 91-93 and give you slightly bump in MPG and Performance. Most if not all modern engine managements can do this, adapt timing based on knock sensing.

[Jamez]

What? All fuels (Gasolines) currently sold in the USA for the most part is E10. You can find some gas stations that might still sell pure gasoline, but they are rare to come across.

There are still some up here that have no or less ethanol. Shell V-Power (in Canada) is supposed to be all gas.

[FissionMailed]

What? All fuels (Gasolines) currently sold in the USA for the most part is E10. You can find some gas stations that might still sell pure gasoline, but they are rare to come across.

This varies based on where you live, too. It's a huge selling point here to have no ethanol, and people advertise it with huge signs and marquees.

[BSD]

Go take a course yourself. I am not here to quote or reference my books.

Most modern engine can run multiple octanes. These days they will run 87 and the ECU will adapt to 93 and add a bit of power by changing timing etc etc etc.. This is not 80s, or the 90s even.

Concur.

[zhenya00]

And you are wrong. The lower the octane the higher the energy content; however, since you cannot run higher compression, and cannot increase the thermodynamic efficiency, it does not make as much power.

You are purposefully being obtuse in order to advance your own ego.

Your statements above were incorrect without qualifications, and what you continue to go on about is misleading. The differences between actual energy contained in the different readily available grades of gasoline is insignificant as far as the average consumer is concerned, pales in comparison to the differences that are readily noticeable by changes in seasonal blends, and make no practical difference at all.

What does make a difference is that if your engine is designed for it, higher octane fuel will provide better performance and economy because even though it may contain (depending on compositional makeup) marginally less stored energy, it extracts far more work from the additional compression it allows.

I stand by my statement that strictly speaking, the octane rating does not indicate anything about the energy content of the fuel. (Else why is it that one branched isomer of octane, 2,2,4-trimethylpentane, has an octane rating of 100, while n-octane, which has a linear arrangement of the 8 carbon atoms, has an octane rating of -10, while having the same chemical formula and virtually the same heating values?)

If you would like to discuss how MTBE or ETBE changes the oxygenate level of the fuel, and the trade-offs of higher octane vs. a lower heating value, let's go ahead. However I sincerely doubt you have specific knowledge as to the exact compositional makeup of any particular brand of gasoline and in any case, that makeup is constantly in flux depending on season and the particular mixture of gasoline any given tanker delivers on any specific day. Frankly I fail to see how this is all that relevant to the specific topic at hand.

Sheesh.

[B3sat16v]

You are purposefully being obtuse in order to advance your own ego.

Your statements above were incorrect without qualifications, and what you continue to go on about is misleading. The differences between actual energy contained in the different readily available grades of gasoline is insignificant as far as the average consumer is concerned, pales in comparison to the differences that are readily noticeable by changes in seasonal blends, and make no practical difference at all.

What does make a difference is that if your engine is designed for it, higher octane fuel will provide better performance and economy because even though it may contain (depending on compositional makeup) marginally less stored energy, it extracts far more work from the additional compression it allows.

I stand by my statement that strictly speaking, the octane rating does not indicate anything about the energy content of the fuel. (Else why is it that one branched isomer of octane, 2,2,4-trimethylpentane, has an octane rating of 100, while n-octane, which has a linear arrangement of the 8 carbon atoms, has an octane rating of -10, while having the same chemical formula and virtually the same heating values?)

If you would like to discuss how MTBE or ETBE changes the oxygenate level of the fuel, and the trade-offs of higher octane vs. a lower heating value, let's go ahead. However I sincerely doubt you have specific knowledge as to the exact compositional makeup of any particular brand of gasoline and in any case, that makeup is constantly in flux depending on season and the particular mixture of gasoline any given tanker delivers on any specific day. Frankly I fail to see how this is all that relevant to the specific topic at hand.

Sheesh.

Watch out I want to inflate my Internet ego. Listen here, what is your background again, do you mind sharing it with us?

[tasty danish]

Watch out I want to inflate my Internet ego. Listen here, what is your background again, do you mind sharing it with us?

It's not his job to list his references. Sound familiar?

You're getting pretty crossed up in your talk about octane. What an engine is intended to run on, and what it is capable of handling are two different things. Don't say that an engine will "gain" power when it runs premium when really it's originally designed and rated to run on that and simply has an ECU that pulls timing when lesser gasoline is used.

That is not the same thing. If I have compression and a tune that maximizes power at 87 octane and I put in 93 while making no tuning changes, I will lose power, period. This fact is well documented, proven, and understood. If I design and tune the engine to run on 93, I will make more power than with 87, and if I try to run 87 I may knock.

[zhenya00]

Watch out I want to inflate my Internet ego. Listen here, what is your background again, do you mind sharing it with us?

In other words you have nothing else to offer here?

I don't know what else to call it when you give purposefully misleading information while condescending to us? My preference is to have a conversation based on mutual respect, however that respect must be earned.

Do you find anything I wrote to be incorrect, or do you want to continue to deflect?

[1.8Tquattro]

My Lexus says 87 can be used in the car, but for maximum performance 91 or higher is recommended. I

Having an engine tuned to run on 91+ and systems in place to prevent it from destroying itself in the event that less than 91 is used is not the same as an engine tuned to 87 increasing performance if 87+ is used.

[SGLoki]

If you are incapable of learning, or admitting you are wrong, you probably have some severe daddy issues, and a very small penis.

Lets pretend that wasn't directed at anyone in particular.

[B3sat16v]

It's not his job to list his references. Sound familiar?

You're getting pretty crossed up in your talk about octane. What an engine is intended to run on, and what it is capable of handling are two different things. Don't say that an engine will "gain" power when it runs premium when really it's originally designed and rated to run on that and simply has an ECU that pulls timing when lesser gasoline is used.

That is not the same thing. If I have compression and a tune that maximizes power at 87 octane and I put in 93 while making no tuning changes, I will lose power, period. This fact is well documented, proven, and understood. If I design and tune the engine to run on 93, I will make more power than with 87, and if I try to run 87 I may knock.

It is apparent that you guys DO NOT read. Modern engine controls systems allow you to run the car in all OCTANE rating. Go read a book or something. This is not the 80s or the 90s.

[B3sat16v]

Having an engine tuned to run on 91+ and systems in place to prevent it from destroying itself in the event that less than 91 is used is not the same as an engine tuned to 87 increasing performance if 87+ is used.

Because you guys design engines all day long, right? How come the SAME engine in the Lexus is used in the Camry and they recommend 87, but yet it makes 268 HP vs 272-275 on the Lexus? It is called modern control systems. That Toyota 2GR-FE has 10.8:1 compression. That is a pretty high CR in my book.

[1.8Tquattro]

Because you guys design engines all day long, right? How come the SAME engine in the Lexus is used in the Camry and they recommend 87, but yet it makes 268 HP vs 272-275 on the Lexus? It is called modern control systems. That Toyota 2GR-FE has 10.8:1 compression. That is a pretty high CR in my book.

Because the Camry is tuned to run on 87, that doesn't mean it will increase performance if 87+ is used.

The Camry makes 268 because the timing is retarded compared to the 270ish Lexus running 91+. (assuming all mechanical components are identical between the two)

No one here is disputing that the same engine can be tuned to run on different octane fuels in different cars.

[B3sat16v]

I don't know what else to call it when you give purposefully misleading information while condescending to us? My preference is to have a conversation based on mutual respect, however that respect must be earned.

Do you find anything I wrote to be incorrect, or do you want to continue to deflect?

Actually, I was wrong, and I did a quick search again and the Octane rating should not really have an impact in BTU/Gal in the gasolines used. So I apologize for that.

There is proven data that many modern manufacturers will tell you 87 is recommended, but due to modern control systems, the engines will advance the timing until a knock is detected. Last time I checked advancing the timing will offer better engine response and a bit more power. Might not be a huge increase, but it certainly is an increase. Same thing happens with Flex fuel engines, the will have more power with ethanol even though Ethanol is about 2/3 the BTU of gasoline. The power increase is not huge, but there is a power increase. Now since ethanol contains less energy the fuel consumption will differ.

On a side note do any of you either design engines/systems that control these engines, or have even taken advance engine courses?

[tasty danish]

Actually, I was wrong, and I did a quick search again and the Octane rating should not really have an impact in BTU/Gal in the gasolines used. So I apologize for that.

There is proven data that many modern manufacturers will tell you 87 is recommended, but due to modern control systems, the engines will advance the timing until a knock is detected. Last time I checked advancing the timing will offer better engine response and a bit more power. Might not be a huge increase, but it certainly is an increase. Same thing happens with Flex fuel engines, the will have more power with ethanol even though Ethanol is about 2/3 the BTU of gasoline. The power increase is not huge, but there is a power increase. Now since ethanol contains less energy the fuel consumption will differ.

On a side note do any of you either design engines/systems that control these engines, or have even taken advance engine courses?

Why do you keep asking that? It's clear by some of your responses that you aren't exactly twirling wrenches every day. And you're awful quick to point out that we can't read while at the same time not reading yourself.

Let me make this clear: JUST BECAUSE YOUR ECU CAN COMPENSATE FOR OCTANE CHANGES DOES NOT CHANGE WHAT OCTANE IS OPTIMAL. You're trying to be cute in saying that you can gain power by simply throwing in higher octane gas, which is false. You gain power by advancing timing. Some ECU's can do this automatically by monitoring knock. That does not make higher octane gas inherently more powerful in any engine. And, if you go dropping 110 octane fuel even in a smart ECU car, you WILL be down on power. Don't post up confusing **** for noobs in the future that may be trying to search and teach themselves.

[B3sat16v]

(1)Why do you keep asking that? It's clear by some of your responses that you aren't exactly twirling wrenches every day. And you're awful quick to point out that we can't read while at the same time not reading yourself.

Let me make this clear: JUST BECAUSE YOUR ECU CAN COMPENSATE FOR OCTANE CHANGES DOES NOT CHANGE WHAT OCTANE IS OPTIMAL. (2)You're trying to be cute in saying that you can gain power by simply throwing in higher octane gas, which is false. You gain power by advancing timing. Some ECU's can do this automatically by monitoring knock. That does not make higher octane gas inherently more powerful in any engine. And, if you go dropping 110 octane fuel even in a smart ECU car, you WILL be down on power. Don't post up confusing **** for noobs in the future that may be trying to search and teach themselves.

I ask because I truly want to know the background of the data being shared here.

Prove it that is false, that a modern engine can run all octanes and gain power from the higher octanes... It is a known fact that ECU can store multiple maps. Why is it hard to understand that it can use these multiple maps using algorithms based of the input data to the ECU.

[GTIVR6MK4]

cleaner gas burns better = higher temperature = extra HP (maybe 0.041% extra power)

youre welcome

[leaftye]

Actually, I was wrong, and I did a quick search again and the Octane rating should not really have an impact in BTU/Gal in the gasolines used. So I apologize for that.

There is proven data that many modern manufacturers will tell you 87 is recommended, but due to modern control systems, the engines will advance the timing until a knock is detected. Last time I checked advancing the timing will offer better engine response and a bit more power. Might not be a huge increase, but it certainly is an increase. Same thing happens with Flex fuel engines, the will have more power with ethanol even though Ethanol is about 2/3 the BTU of gasoline. The power increase is not huge, but there is a power increase. Now since ethanol contains less energy the fuel consumption will differ.

On a side note do any of you either design engines/systems that control these engines, or have even taken advance engine courses?

Does that even make sense? You're saying that where an older engine may be tuned to run with a certain type of gas without any knocking whatsoever under normal conditions, modern ECU's are created to knock.

[x_GTI_x]

In my cabby I havent been running anything but 93 for 2 years now, stock ECU - no problems at all.

But from research on cabby-info and common sense, I was told running 93 would help clean up the fueling system... at 200k mi. it needs all the help it can get.

in the first month or so of filling up with 93, the entire car ran that much smoother, was there an HP gain? nothing noticeable... but acceleration and idle felt much smoother.

[B3sat16v]

Does that even make sense? You're saying that where an older engine may be tuned to run with a certain type of gas without any knocking whatsoever under normal conditions, modern ECU's are created to knock.

Do you lack common understanding of the English language? A modern ECU will continue to advance the timing until a knock is detected along other things that it can do. This allows it to compensate for multiple octane ratings. It will continue to attempt to provide the best performance until a knock is detected, then it retards timing to a lower value to prevent the knock. So if you fuel it up with 93 vs 87 the performance will be greater. I am not talking about a huge improvement here, but an improvement is an improvement.

If you go read about Ford's ECU, they all mostly do this. The new 3.7 V6 is rated for 87, but will in-fact allow 93 with a boost in power. Their new 5.0 V8 does as well. Most modern cars will allow you to run an array of octanes due to the fact that sensors and processing power is a lot better than it was even ten years ago.

[leaftye]

Do you lack common understanding of the English language? A modern ECU will continue to advance the timing until a knock is detected along other things that it can do. This allows it to compensate for multiple octane ratings. It will continue to attempt to provide the best performance until a knock is detected, then it retards timing to a lower value to prevent the knock. So if you fuel it up with 93 vs 87 the performance will be greater. I am not talking about a huge improvement here, but an improvement is an improvement.

If you go read about Ford's ECU, they all mostly do this. The new 3.7 V6 is rated for 87, but will in-fact allow 93 with a boost in power. Their new 5.0 V8 does as well. Most modern cars will allow you to run an array of octanes due to the fact that sensors and processing power is a lot better than it was even ten years ago.

Do you lack a common understanding of the English language? You're saying that a modern ECU will keep trying to knock in hopes that it won't knock.

[leaftye]

Hey everyone, we're supposed to trust B3sat16v because he won't provide references or his credentials, but because he'll insult you while making statements that don't make sense.

[B3sat16v]

Do you lack a common understanding of the English language? You're saying that a modern ECU will keep trying to knock in hopes that it won't knock.

Do you understand how a knock sensor works? Or what creates the knock in the first place? How they communicate with the ECU? What data they provide the ECU?

[B3sat16v]

Hey everyone, we're supposed to trust B3sat16v because he won't provide references or his credentials, but because he'll insult you while making statements that don't make sense.

You do not have to trust me, but if you researched a little bit, you will realize how amazing modern electronics are and how capable they can be. You should also research FLEX Fuel cars. It is amazing how they can gain power with the higher octane rated Ethanol. Maybe that will learn you something.

[leaftye]

A modern ECU will continue to advance the timing until a knock is detected along other things that it can do.

due to modern control systems, the engines will advance the timing until a knock is detected.

It's funny how when I call you out on this statement, you get pissy, then say the same thing. Once again, you're saying that modern ECU's will try to knock.

[McBanagon]

I was filling up my gf's Jetta tonight, and I got to wondering.

Does the octane used add or decrease the longevity of a motor in a car? For example, she's a 2.5L so if I put in 93 as opposed to 87 am I going to increase longevity or just pay more for some extra oomph essentially?

I suppose we can throw the oil debate in here too, how often is too much or too little. She goes the 10k mark, I go by the 5k on mine.

To answer the OP, the answer is no. Do what the manual says, which is probably 87. Add a bottle of Seafoam once/twice a year, and that's it.

/movingontothenextthread

[digraph]

B3sat16v you are too patient. You're not going to get a real technical discussion on TCL. You are going to get 100 anecdotes where people will draw the facts from the conclusions. Good luck.

[leaftye]

Now where B3sat16v thinks flex fuel cars continuously try to knock to detect if E85 is being used, I think it's more likely that the O2 sensor is being checked continuously. This in fact is normal. Because E85 puts out less energy, it would cause a leaner burn. Once the ECU is out of its startup sequence, it'll detect a lean condition and add fuel. This is normal. Any old OBDII ECU will do that. The difference with a flex fuel ECU is that it should eventually switch to a map that's optimized for E85, or even be more flexible while transitioning between partial tanks of fuel.

[B3sat16v]

It's funny how when I call you out on this statement, you get pissy, then say the same thing. Once again, you're saying that modern ECU's will try to knock.

Again do a research, you will realize that is how they work.

the ECU has been reprogrammed with adaptive-knock spark control. If the two knock sensors embedded in the cylinder block don't hear knocking, the ECU will keep advancing the spark until it does.

Read more: http://www.musclemustangfastfords.co...#ixzz1urbzJOba

[B3sat16v]

Now where B3sat16v thinks flex fuel cars continuously try to knock to detect if E85 is being used, I think it's more likely that the O2 sensor is being checked continuously. This in fact is normal. Because E85 puts out less energy, it would cause a leaner burn. Once the ECU is out of its startup sequence, it'll detect a lean condition and add fuel. This is normal. Any old OBDII ECU will do that. The difference with a flex fuel ECU is that it should eventually switch to a map that's optimized for E85, or even be more flexible while transitioning between partial tanks of fuel.

Again you have not a clue how modern engine control systems work. When I mention Flex fuel was for you to blow your own head learning how they work. The fact that the systme works so seamsly is amazing. And just proving you that ECU can have multiple maps embeded and will switch maps besed on algorithms of the input data.

When I talk about time advance and knock I am talking about gasoline only cars.

[Knock Sensor]

The only advantage to using the higher octane fuel in a car that doesn't recommend or require it is the added detergents which keep the injectors cleaner. Using regular seems to require doing a top end cleaning every couple years, while vehicles running premium don't seem to need it.

My old jetta was run on 87 its whole life, (give or take previous owners, but it was a lowly 2.slow so I doubt it got premium), I had that car from 120,000 to 180,000 miles. Having had the valve cover off a few times near the end of my ownership, that thing was clean as a whistle and never had injector problems. No sludge, no nothing.

Hell I even seafoamed my protege (65,000 miles) trying to fix another problem and I barely got any smoke to come out the tail pipe. Turned out some emissions valve was stuck. So I kinda doubt running 93 will keep the top end from sludging more so than running 87, based on my experience.

[leaftye]

Again do a research, you will realize that is how they work.

Again, do your research.

Any old OBDII ECU will spark retard.

You think that link you posted is reference? Wow.

Try something reputable, like: http://papers.sae.org/2006-01-0607/

Look at that, maps are still involved. Now try using an iota of common sense here B3sat16v. I know it's difficult, especially since you have no credentials to post, or even a reputable reference.

Here's how it works. An ECU has a map that is optimized for a certain octane of fuel. If it detects knock, it switches to a map for a lower octane of fuel. Even the old ECU in my 1998 car does that. Calling it "adaptive" is just marketing hype.

[leaftye]

Again you have not a clue how modern engine control systems work. When I mention Flex fuel was for you to blow your own head learning how they work. The fact that the systme works so seamsly is amazing. And just proving you that ECU can have multiple maps embeded and will switch maps besed on algorithms of the input data.

When I talk about time advance and knock I am talking about gasoline only cars.

It's funny how when you say I'm right, you still try to say I don't have a clue, yet you've explained absolutely nothing. You don't exhibit any technical knowledge, common sense or even the ability to post a reputable reference. You even ridicule someone else for not posting their credentials, yet you won't even do the same.