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Car Forum / Dodge / Dodge Trucks / June 2005Will high octane really damage my engine?
As some of you know, I'm a 2001 Dakota owner who is currently stationed overseas. The base just upgraded the gas station, and in their infinite wisdom, now only offer 95 Octane gas. My owner's manual says my engine could be damaged if I use high octane. Will it really? If this can indeed damage my engine, I'd like to know how, and if, there's any way (additives?) I'd be able to use this gas. Otherwise, I have to use more expensive options, which may include paying the current $6.50 per gallon, which is what we pay here, with the currently high exchange rate. Thanks for any advice! jmc N, but it will your wallet. Steve > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 9 lines] > > jmc >N, but it will your wallet. That part is really debateable because some modern hi compression engines really need more than 87 to run at their fullest potentail and will run better and get better fuel mileage with it. While maybe they might not all gain, all for my vehicals do especailly in hot weather and even my wife 4cyl 2000 Cherokee runs noticably smooth at speed and picks up 1 or 2 mpg as well when she uses it during the warmer months. Besdie at today prices it is only 4 to 6% for premium and I gain more than that back in performance and MPG in my cars so it is actually cheaper to run premium for me. Wow. I always thought it could do damage if you went the other way (putting lower octane gas into an engine requiring high, although today's engines can compensate for it). Years ago, when gas was cheaper (heh, heh. remember when?) I would sometimes put higher octane gas in my car, even though it served no purpose whatsoever in my car. I'm curious to know the answer to your question. > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 9 lines] > > jmc It is possible BUT not very likely. The higher octane fuel additives MAY not burn off as well and could result in carbon deposit buildup on the heads. Easy solution would be to use some cleaner every few thousand miles to prevent it from occurring. Oh and thank you. Keep your head down.  SignatureSteve W. > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 10 lines] > > jmc >It is possible BUT not very likely. The higher octane fuel additives MAY >not burn off as well and could result in carbon deposit buildup on the >heads. Easy solution would be to use some cleaner every few thousand >miles to prevent it from occurring. Or the good Polish tune-up" Never had a car as a youngster that had any danger of caboning up, regardless what was used for fuel!!! >Oh and thank you. Keep your head down. IIRC, the problem with using high octane fuel stems from the computer. It seems that the longer burn time of higher octane fuel fools the computer into thinking that the engine is running rich and causes it to lean the engine out. Running lean itself is not a particularly good thing for the engine and will be reflected in a loss of power, not to mention heat which could cause detonation, another bad thing for the engine. SignatureIf at first you don't succeed, you're not cut out for skydiving > It is possible BUT not very likely. The higher octane fuel additives MAY > not burn off as well and could result in carbon deposit buildup on the [quoted text clipped - 26 lines] > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups > ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- >IIRC, the problem with using high octane fuel stems from the computer. > It [quoted text clipped - 7 lines] >which >could cause detonation, another bad thing for the engine. This could not be further from the truth and does not warrant further comment. So why would you disagree with something that is fact? What do you know that the law of Physics and Electronics doesn't? >>IIRC, the problem with using high octane fuel stems from the > [quoted text clipped - 13 lines] > This could not be further from the truth and does not warrant further > comment. > >IIRC, the problem with using high octane fuel stems from the > computer. [quoted text clipped - 11 lines] > This could not be further from the truth and does not warrant further > comment. And those that cannot or do not explain there answers are usually full of sh.t. SignatureIf at first you don't succeed, you're not cut out for skydiving >> >IIRC, the problem with using high octane fuel stems from the >> computer. [quoted text clipped - 20 lines] >of >sh.t. No, only those that claim thing that are without merit like premium being harmfull. I could go into a long explaination why but you have already made up your mind so it is would be a wasted effort but I would explain why to anyone else that honestly wants to know why. > >> >IIRC, the problem with using high octane fuel stems from the > >> computer. [quoted text clipped - 26 lines] > already made up your mind so it is would be a wasted effort but I > would explain why to anyone else that honestly wants to know why. First of all, I never claimed it, that would be the manufacturer who I would believe, knows far more about their vehicle than you do. Second, your childish response further proves that you really don't know WTF you are talking about here. SignatureIf at first you don't succeed, you're not cut out for skydiving > > >> >IIRC, the problem with using high octane fuel stems from the > > >> computer. [quoted text clipped - 31 lines] > childish response further proves that you really don't know WTF you are > talking about here. you want some real grins ? check out his idiotic responses about GM AC in alt.autos.4x4.chevy.trucks " Leprechaun in Suburban AC unit" and in alt.trucks.ford in "91 f150 towing capacity" where his claim to his knowledge about the AOD is " Probaly a lot more familar with transmisson and gear limitations than you think! I actually have a working 83 AOD in the barn right now. (pull from a vehical I junked out)" > > > >> >IIRC, the problem with using high octane fuel stems from the > > > >> computer. [quoted text clipped - 37 lines] > check out his idiotic responses about GM AC in alt.autos.4x4.chevy.trucks " > Leprechaun in Suburban AC unit" Hahahahaha, now that was funny. I think that I believe more in the Leprechaun than in his "gas hammer". > and in alt.trucks.ford in "91 f150 towing capacity" > [quoted text clipped - 3 lines] > think! I actually have a working 83 AOD in the barn right now. (pull from a > vehical I junked out)" Unfortunately, RR's news server no longer has most of that thread so I have no idea what he said there but that's just as well since I don't know what AOD stands for either. I am assuming Automatic Over Drive and if that is what it is, how exactly does his having an old trans in his barn make him an expert on them? SignatureIf at first you don't succeed, you're not cut out for skydiving >>>> IIRC, the problem with using high octane fuel stems from the >>>> computer. It [quoted text clipped - 22 lines] > already made up your mind so it is would be a wasted effort but I > would explain why to anyone else that honestly wants to know why. Classic! > And those that cannot or do not explain there answers are usually full of > sh.t. Your typical warped logic didn't deserve any explanation. Heres your logic, high octane fuel causes the computer to lean the mixture which causes increased heat which in turn causes detonation (I assume you mean pinging). Somebody really needs to explain why this is warped to you? > > And those that cannot or do not explain there answers are usually full of > > sh.t. > > Your typical warped logic didn't deserve any explanation. What's the matter Miles? Are you still upset? Perhaps you should do a little research before jumping in and making an a.s out of yourself. Perhaps if you knew anything about how an engine actually runs and how modern emissions systems actually work you would not be so quick to jump in and attack. > Heres your > logic, high octane fuel causes the computer to lean the mixture which > causes increased heat which in turn causes detonation (I assume you mean > pinging). Pretty much, but like I said, if you knew half as much as you think you do, you would see the possibility. To further reduce emissions for areas like California where they are very strict, tighter tolerances are required. Then when you add the exceptionally high cost of fuel, especially premium, it is easy to make the assumption that if a vehicle is not to be used for high performance applications, the engine could and would be designed around the characteristics of regular unleaded. This could include things like fuel delivery rates, valve timing, ignition timing, computer curves based on the fuels rate of burn and anti-knock capabilities .... get the picture yet????? If the fuel burns slower than the engine and its control computers curves were designed for, the O2 sensor is going to detect a false rich run condition because some of that fuel is going to enter the exhaust unburned. I would think that even you could understand this much. Now unless your engine has variable valve timing, there are really only two ways to deal with this situation, increase the timing and/or cut back the fuel. I would hope that even you could understand this much. Now, since the fuel curves are based on the properties of regular unleaded AND set up for minimum emissions while giving maximum available power, I think that it would be fairly easy to assume that the timing would always be at or near its maximum setting for any given speed and load. That would leave the computer with the simple choice of reducing the injector pulse width (cutting back the fuel amount) to correct what it sees as a rich condition. The problem is that by doing this, what it has actually done is cause a lean run condition. I guess that you don't know this but unlike a diesel, a gas engine requires a very specific air / fuel ration to run properly. If you run it lean, it will increase cylinder temps and reduce power. I have read posts in here where people noticed power loss when running high octane fuel in engines where the manufacturer stated not to use it. Why do you think that is "all knowing one"? This lean run condition also makes the fuel charge unstable and combined with the added heat, there is the increased possibility of detonation and pre-ignition, both of which can cause damage to the engine, hence, the manufacturers claims of "possible engine damage". Here is a link explaining detonation and pre-ignition. http://www.hastingsmfg.com/Service%20Tips/detonation_and_preignition.htm Notice the number 1 reason for detonation and the number 4 reason for pre-ignition pretty much follows what I was saying. Then on top of that there is the possibility of the increased cylinder wall temps burning off the protective film of oil causing increased wear, even without any detonation or pre-ignition. You can also look at the wording from the manufacturer. If they were simply saying not top use premium fuels, you could also assume that they were more concerned about the detergents added to that grade damaging fuel injection components rather than confusing the computer but from what I have seen posted, they were instead specifically talking octane ratings which would lead me to believe that they were more concerned about the fuel rate of burn and it confusing the computer rather than detergent damage. Now, does this guarantee that I am correct, nope. What I am saying is simply based on knowledge of how a modern fuel injected engine operates and what could go wrong as well as the wording of the warning and symptoms reported by posters in this group which is far and away more than anything that you have provided so as they say, put up or shut up. > Somebody really needs to explain why this is warped to you? Yep, so I suggest that you either get started or mind your own business. The sad thing is Miles that you do seem to be a bright guy and we could have some interesting conversations if you didn't resort to turning everything into some sort of personal attack. I'll admit that I was just as bad at one time but I have stopped doing that a while ago. Perhaps if or when you realize that it simply isn't worth the trouble doing that we can get into some interesting discussions and or debates... SignatureIf at first you don't succeed, you're not cut out for skydiving > What's the matter Miles? Are you still upset? Perhaps you should do a > little research before jumping in and making an a.s out of yourself. Perhaps > if you knew anything about how an engine actually runs and how modern > emissions systems actually work you would not be so quick to jump in and > attack. lol, geez, me upset? you just posted a frigg'n couple pages of rambling twisting nonsense. Your own reply actually had part of the reason your logic is warped but you discounted it. Higher octane fuel causes modern engines to ping. lol > > What's the matter Miles? Are you still upset? Perhaps you should do a > > little research before jumping in and making an a.s out of yourself. Perhaps [quoted text clipped - 6 lines] > your logic is warped but you discounted it. Higher octane fuel causes > modern engines to ping. lol And yet, even though you call it nonsense, you were once again unable to disprove any of it. This is really getting to be a habit with you Miles. Instead, you just ramble on making claims that show your complete lack of understanding of the operation of a modern computer controlled fuel injected engine. And yes, if the slower burn rate of a higher octane fuel confuses the computer and causes it to put the engine into a lean run condition (the number 1 cause of detonation in the link I gave you), it in fact can cause it to PING. 93 octane fuel is far from ping proof and it is obvious that you simply didn't understand anything. You did however manage to prove me wrong on one point. I did say that I thought you were a bright guy but after this response....Congratulations. SignatureIf at first you don't succeed, you're not cut out for skydiving > And yet, even though you call it nonsense, you were once again unable to > disprove any of it. Read your own rambling 2nd reply again...Especially all those If If If's...ya, IF!! Thats the point TBone. All those If's of yours aren't typical at all. Not even close. > > And yet, even though you call it nonsense, you were once again unable to > > disprove any of it. > > Read your own rambling 2nd reply again...Especially all those If If > If's...ya, IF!! Thats the point TBone. All those If's of yours aren't > typical at all. Not even close. LOL, you really are funny Miles. There was nothing rambling about it, you either just can't understand it or you are just not man enough to admit to possibly being wrong. I believe that it is a lot of both. LOL, and I thought that I was bad. Please prove even one of my points wrong, oh, that's right, you can't and yet, you still insist on me being wrong. Sorry Miles, but until you do, you are just being a whining crybaby that just likes to argue with nothing to back it up. SignatureIf at first you don't succeed, you're not cut out for skydiving > LOL, you really are funny Miles. There was nothing rambling about it, you > either just can't understand it or you are just not man enough to admit to [quoted text clipped - 3 lines] > Miles, but until you do, you are just being a whining crybaby that just > likes to argue with nothing to back it up. TBOne, look at that crap you just wrote! If that ain't a pure sad lonely troll! Geez, some ppl's kids. Crap doesn't need to be proven wrong! Now be silent! > > LOL, you really are funny Miles. There was nothing rambling about it, you > > either just can't understand it or you are just not man enough to admit to [quoted text clipped - 5 lines] > > TBOne, look at that crap you just wrote! Yawn. Like I said, no real knowledge, just wanting to argue. > If that ain't a pure sad lonely troll! Now that would be you with your childish arguments that you are unable to back up. > Crap doesn't need to be proven wrong! While true, you are even unable to prove what I said was crap although with your proven lack of knowledge in this area, I can see why not. > Now be silent! Perhaps you should follow your own advice Miles and learn a little something about vehicles before jumping in and proving your ignorance on the subject. As for me, since you are completely unable to make any point at all, I'm done with this. SignatureIf at first you don't succeed, you're not cut out for skydiving > As for me, since you are completely unable to make any point at all, I'm > done with this. lol, another several paragraphs of drabble out of you...and yet you're done with this? lol. Too funny but I hope you keep your word. >And yet, even though you call it nonsense, you were once again unable to >disprove any of it. This is really getting to be a habit with you Miles. [quoted text clipped - 7 lines] >wrong on one point. I did say that I thought you were a bright guy but >after this response....Congratulations. You are ASSuming that burn rate and octane rating are related. also ASuming higher octane fuel burns slower. This ASumption is not necessarily true. The burn rate of a fuel is a measurement of the time required for complete combustion of the air/fuel mixture. The notion that octane ratings affect the burn rate of fuel is about 180-degrees from reality. Burn rate is a function of several variables, and the two are completely independent. Although there is generally a correlation between octane ratings and burn rates, the fuel mixture ratio has a lot more effect on burn rate than octane rating does. To give you a good example of this, Jim Wurth from Sunoco Race Fuels. explains, "A perfect example is Sunoco Maximal, which is our fastest burning fuel, and coincidentally one of Sunocos highest octane fuels at 116 (R+M)/2. A lot of Pro Stock teams rely on Maximal for those sub-seven second runs. When they are turning 9,000rpm or more, the fuel has to burn pretty quickly to achieve complete combustion." However he also says AVIATION high octane fuel has a significantly lower burn rate, being designed to run in engines running at 3000RPM and less. It is not a good idea to run AvGas in a car. BUT - add a small amount of leaded AvGas to unleaded MoGas, and the octane increases significantly more than the mathemathical ratio would suggest, without slowing the burn rate appreciably. One reason some people think octane and burn rate are related is because some (most) high octane fuels are lower in Specific Gravity (below 0.75)than regular unleaded (generally 0.75 or higher), which causes the engine to actually run leaner. Burn rate of a lean mixture is slower than burn rate of a rich mixture. This is not uneducated conjecture - it is from fuel company experts. > You are ASSuming that burn rate and octane rating are related. also > ASuming higher octane fuel burns slower. This ASumption is not > necessarily true. But it is not false either and I am not the one saying high octane fuel will cause damage to certian engines, the MANUFACTURER is!!! I am simply giving a possible reason as to why. > The burn rate of a fuel is a measurement of the time required for > complete combustion of the air/fuel mixture. The notion that octane > ratings affect the burn rate of fuel is about 180-degrees from > reality. Really, how? Octane is a level of fuel stability and it is impossible to make a given fuel more stable without affecting the burn rate. > Burn rate is a function of several variables, and the two are > completely independent. Although there is generally a correlation > between octane ratings and burn rates, the fuel mixture ratio has a > lot more effect on burn rate than octane rating does. Hahahaha, talk about doubletalk. While as you say, many variables that can effect the burn rate, there cannot be a correlation between octane ratings and burn rate unless octane ratings effect the burn rate as well, regardless of the effect the mixture or other variables may also have on it. > To give you a good example of this, Jim Wurth from Sunoco Race Fuels. > explains, "A perfect example is Sunoco Maximal, which is our fastest > burning fuel, and coincidentally one of Sunoco's highest octane fuels > at 116 (R+M)/2. A lot of Pro Stock teams rely on Maximal for those > sub-seven second runs. When they are turning 9,000rpm or more, the > fuel has to burn pretty quickly to achieve complete combustion." Do you really think that you can put this in your car and it will run ok????? You are also comparing apples to airplanes. This is a racing fuel refined for specific needs that are very different than that of automotive fuel. If you dropped the octane rating of this specific fuel, it would burn even faster but at a cost of significant instability that is simply not worth the small increase in speed. > However he also says AVIATION high octane fuel has a significantly > lower burn rate, being designed to run in engines running at 3000RPM > and less. It is not a good idea to run AvGas in a car. It would not be a good idea to put either one of these fuels in a modern fuel injected vehicle. Either one would make the vehicle run like sh.t because the computer is not set up for the characteristics of either one of these fuels. > BUT - add a small amount of leaded AvGas to unleaded MoGas, and the > octane increases significantly more than the mathemathical ratio would > suggest, without slowing the burn rate appreciably. But here is the key word, appreciably. IOW, it WILL slow down the burn rate, just not by a huge amount. The problem is that it doesn't have to be slowed down by a huge amount for a computerized emissions specific computer to react to it. > One reason some people think octane and burn rate are related is > because some (most) high octane fuels are lower in Specific Gravity > (below 0.75)than regular unleaded (generally 0.75 or higher), which > causes the engine to actually run leaner. You really need to stop talking out of both sides of your mouth. For any SPECIFIC FUEL TYPE, a change in octane reflects a change in the burn rate. Comparing different fuel formulations and types is like comparing apples to grapes, regardless of the octane ratings. When you can provide proof that for a specific fuel, changes in the octane ratings have no effect AT ALL on the burn rate, then you win and perhaps you can then inform the manufacturers of the vehicles that they are wrong and should remove their bogus warnings as well but until then... > Burn rate of a lean mixture is slower than burn rate of a rich mixture. Ok, I'm not going to argue this or the reasons for it but lets put your claim to work. For a specific fuel type and or make, an increased octane rating indicates a slower burn rate and nothing that you have said so far says anything different. If the computer in the vehicles with this warning are configured based on the burn rate of REGULAR unleaded with tight emission tolerances, the slightly slower burn rate of super will cause the computer to see a rich condition. Since these computers are configured to control emissions over performance, it will probably cut back the injector pulse width to lean out the mixture. Now according to you, that will slow the burn rate down even further and may make the computer think that the problem has not improved enough for the current reduction or may have gotten worse. Either way , now it will further lean out the mixture and / or increase the timing until the O2 sensor indicates that the emissions are within specifications. Lean mixtures burn hotter and are far more unstable and likely to ping than the correct mixture and combined with advanced timing.... You really need to look at the complete picture. The computer controls the mixture depending on what it sees on the emission side and if it thinks it is delivering too much fuel based on excess unburned fuel entering the exhaust, it will cut it back, possibly to the point of causing damage over time. SignatureIf at first you don't succeed, you're not cut out for skydiving > Really, how? Octane is a level of fuel stability and it is impossible to > make a given fuel more stable without affecting the burn rate. I see you are up to your usual bullshit. You obviously don't understand what octane does for a fuel. Shut up now. SignatureMax Give a man a match, and he is warm for a short while. Light him on fire, and he is warm for the rest of his life. >> You are ASSuming that burn rate and octane rating are related. also >> ASuming higher octane fuel burns slower. This ASumption is not [quoted text clipped - 106 lines] > causing > damage over time. Hey Max. what's up. Talk about PKB, now GFY SignatureIf at first you don't succeed, you're not cut out for skydiving > > Really, how? Octane is a level of fuel stability and it is impossible to > > make a given fuel more stable without affecting the burn rate. [quoted text clipped - 113 lines] > > causing > > damage over time. > Hey Max. what's up. Talk about PKB, now GFY Oooh, acronym soup. Yer so fulla sh.t, its spewing out yer mouth. You ought to try opening your a.shole as much as you open your mouth, then that stuff would go out the right way. SSDD with you, the ultimate PITA. Wow, I can do that too. Your turn! SignatureMax Give a man a match, and he is warm for a short while. Light him on fire, and he is warm for the rest of his life. > Hey Max. what's up. Talk about PKB, now GFY > [quoted text clipped - 142 lines] >> > causing >> > damage over time. >> You are ASSuming that burn rate and octane rating are related. also >> ASuming higher octane fuel burns slower. This ASumption is not [quoted text clipped - 90 lines] >entering the exhaust, it will cut it back, possibly to the point of causing >damage over time. T-Bone - I'm not going to get into an arguement here - but the fact is that the burn rate varies more from manufacturer to manufacturer, within the same "grade" of gasoline, than it does from regular to hi-test in a particular brand. There are MANY ways to change the octane rating of fuel - some of which will have more effect on burn rate than others. I do not think the burn rate has as much effect on the emissions systems of todays cars as you think it does. First of all, the O2 sensor, which is the ONLY part of the system that monitors the mixture, has no idea how much fuel was unburned - only the amount of oxygen in the exhaust. Granted - this IS a pretty good indicator of how well the fuel is being burned - but by the time the slow burning fuel in your description hits the O2 sensor it has more or less completed it's burn, whether it has converted its heat energy into torque (cyl pressure) or not. If the fuel has not completed it's burn, the O2 sensor will sense excess oxygen, which it will interpret as a LEAN mixture - not rich - and it will RICHEN the mixture to compensate. Since the mixture strength has significantly more effect on burn time than octane change does, the burn time will speed up with the richened mixture, compensating and bringing the oxygen level in the exhaust back down to within range. If the O2 level in the exhaust drops too far, the engine compensates by leaning the engine - which causes the burn rate to slow down, restarting the cycle. This can happen at close to 8000 times a minute on a 4 cyl engine at 4000 RPM - or 12000 times a minute at 6000 RPM. Add to this the fact that MOST engines now have knock sensors, with adaptive ignition timing. The engine runs as advanced as possible at all times. This means the burn time is less critical than if the engine was running later ignition timing. Timing is only retarded when the knock count reaches a given (programmed) knock threshold. This knock threshold is reached earlier with low octane fuel than with premium. All of this is NOT to say that some of today's engines MAY not have an adverse reaction to high-test fuels - but that if they do it is for a different reason. A POSSIBLE reason is that IF the burn rate is too slow, and IF that causes the O2 sensor to tell the computer it is running too lean, and IF the computer overcompensates, causing the engine to actually run richer - and IF this causes the engine to carbon up, THIS could contribute to engine knock/detonation by both raising compression ratio and causing hot spots in the cyl (glowing carbon). We KNOW that certain vehicles built in the last 15 years have a carbon deposit problem under certain conditions, and that this causes detonation problems on these vehicles. Dodge Colts and Toyota Tercels are two examples of these vehicles. Whether fuel octane ratings contribute to this problem or not is strictly a matter of conjecture at this time - but my FEELING is it does not - as the problem exists on vehicles run exclusively on regular fuel - I can't say if it happens as often or as severely as on vehicles run on hi-test - so this is not the ONLY explanation, if indeed it is valid at all. I'm not saying I totally understand the entire combustion process - but as you may remember I have taught the trade in the past, and have a little bit more than a passing aquaintance with engines and engine control systems and theory. There are a LOT of theories out there - many of which do not stand up to close scrutiny. What we DO know is the manufacturers will "cover their behinds" in as many ways as possible when it comes to legal mumbo-jumbo, and if there is any possibility that CAFE and or emissions standards MAY be compromized by use of a given (not manufacturer supplied) product, they WILL warn against it's use. But will they fix "known" mechanical or safety problems if the accountants think they can play the odds and buy off the "victims" cheaper than fixing the problem???? We all know the answer to that one too. Just some more to think about. Have a good weekend. > Just some more to think about. Have a good weekend. Excellent response, thank you. It appears that I got my fuel burn rates regarding rich / lean mixtures completely backwards, oh well. Now it looks to me like those warnings could be to prevent a possible rich run condition that would cause premature converter failures that the companies would have to pay for. You have a good weekend as well and thanks again. SignatureIf at first you don't succeed, you're not cut out for skydiving > It appears that I got my fuel burn rates > regarding rich / lean mixtures completely backwards, oh well. We'll await the apologies you owe for calling people names and being rude when you were in fact, wrong. Probably won't happen, oh well. SignatureMax Give a man a match, and he is warm for a short while. Light him on fire, and he is warm for the rest of his life. >> Just some more to think about. Have a good weekend. > [quoted text clipped - 6 lines] > have > to pay for. You have a good weekend as well and thanks again. LOL, nice try Max but the truth is that you didn't say anything of value in your previous post and as usual trying to take credit for someone else's knowledge. BTW, who is the we you are talking about? Go back to your corner troll boy. SignatureIf at first you don't succeed, you're not cut out for skydiving > > It appears that I got my fuel burn rates > > regarding rich / lean mixtures completely backwards, oh well. [quoted text clipped - 12 lines] > > have > > to pay for. You have a good weekend as well and thanks again. > LOL, nice try Max but the truth is that you didn't say anything of value in > your previous post and as usual trying to take credit for someone else's > knowledge. BTW, who is the we you are talking about? Go back to your > corner troll boy. Nice try at avoiding an apology TBone. You ranted all over against me saying I didn't know how engines worked. Who gives a rats a.s about credit. Is that what this is all about to you? Fact is, you were wrong and are not big enough to apologize for your long winded rants. What is it exactly that I'm supposed to apologize for Miles? SignatureIf at first you don't succeed, you're not cut out for skydiving > > LOL, nice try Max but the truth is that you didn't say anything of value in > > your previous post and as usual trying to take credit for someone else's [quoted text clipped - 5 lines] > credit. Is that what this is all about to you? Fact is, you were wrong > and are not big enough to apologize for your long winded rants. > What is it exactly that I'm supposed to apologize for Miles? lol. Figures! Rant away then claim you're clueless. > LOL, nice try Max but the truth is that you didn't say anything of value > in > your previous post Thats correct, to a point. While I didn't contribute to the subject, I did tell you to shut up. Thats got plenty of value in several peoples view, I'd bet on it. > and as usual trying to take credit for someone else's > knowledge. Rubbish. I did nothing of the sort. I told you that you didn't understand octane, and the guy with the knowledge proved exactly what I said, you hadn't a clue. > BTW, who is the we you are talking about? I bet Miles at the very least is part of the "we" that deserves an apology for the crap you spew. > Go back to your > corner troll boy. LOL, speaking of PKB.... Your turn!! SignatureMax Give a man a match, and he is warm for a short while. Light him on fire, and he is warm for the rest of his life. > LOL, nice try Max but the truth is that you didn't say anything of value > in [quoted text clipped - 22 lines] >> > have >> > to pay for. You have a good weekend as well and thanks again. Suddenly, without warning, nospam.clare.nce@sny.der.on.ca exclaimed (12-Jun-05 2:30 AM): >>>You are ASSuming that burn rate and octane rating are related. also >>>ASuming higher octane fuel burns slower. This ASumption is not [quoted text clipped - 162 lines] > > Just some more to think about. Have a good weekend. Ok, now I'm getting a bit lost. In your opinion, if I use "Premium" high octane (95) fuel (whatever formulation they use here in the UK) will there be damage my engine, whether it runs rich, lean, or within specs? jmc >> Just some more to think about. Have a good weekend. > [quoted text clipped - 4 lines] > >jmc In my opinion? not very likely. If a car run on premium actually does run richer, driving it a bit harder (which most premium users will do by instinct)will help chase out any carbon build-up. If it runs lean, unless you are chasing it's tail very hard, you will not have an overheating problem - you may have driveability problems - but I doubt it. If it runs within specs, no problem. You MIGHT end up with a damaged catalitic converter, but whether that would hapen significantly sooner than normal is rather doubtful. Just my (somewhat educated) opinion on the subject. Suddenly, without warning, nospam.clare.nce@sny.der.on.ca exclaimed (11-Jun-05 9:20 PM): >>And yet, even though you call it nonsense, you were once again unable to >>disprove any of it. This is really getting to be a habit with you Miles. [quoted text clipped - 40 lines] > > This is not uneducated conjecture - it is from fuel company experts. Ok, so assuming this is true, how would I figure out if this particular fuel is safe? jmc >Ok, so assuming this is true, how would I figure out if this particular >fuel is safe? > >jmc Check the Specific Gravity of the fuel. If within points of 0.750 I wouldn't worry. Suddenly, without warning, TBone exclaimed (09-Jun-05 6:33 PM): >>>And those that cannot or do not explain there answers are usually full > [quoted text clipped - 82 lines] > realize that it simply isn't worth the trouble doing that we can get into > some interesting discussions and or debates... TBone, thank you for this. I may not be a mechanic but this is exact sort of explanation I was looking for - con *or* pro. I missed it originally in some of the, uh, excess posts my question has engendered, and I've still to catch up with what is below, but the wording in my manual does indeed specifically mention octane ratings. I don't have it in front of me, but seem to remember it suggested using fuel with no higher than 87 octane. 95's a bit beyond that. For those who happen to disagree, please post an explanation as to why not, unless you have already and I just haven't made it that far down the thread. 'Course, at the moment the question's moot. The garage closed the next day, due to receiving a possibly contaminated load of fuel - just-fueled vehicles started sputtering nearly immediately after leaving the station, from what I hear. jmc > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 9 lines] > > jmc I wouldn't lose a minutes sleep over it. I imagine that your owners manual when talking about high octane is referring to 100+ octane racing fuel but, still I don't know why it would harm the engine. Higher octane fuel doesn't ignite as easily as lower octane fuel. With higher octane fuel you have a more controlled burn than with lower octane fuel and that is why you have detonation with low octane fuel because it so easily ignites = pre-ignition. With today's newer engines many have a higher compression ratio than they had 10 years ago. The computers on today's vehicles try to adjust for the lower octane fuel to keep them from the pinging pre-ignition. Back in the late 60's when you had such high horsepower engines coming stock in musclecars they were running 10:1 compression or higher and they had higher octane fuel at the local gas station. Now we've got the high compression ratios back in quite a few new engines and are using the computers to retard the timing so that they run on 87 octane fuel without damaging the engine from lack of octane. If the compression ratio of your engine is not high enough to require high octane fuel then you don't need it. 2 octane points above the normal premium gas here in the states will make next to no difference at all except your engine may run better and cooler and if it pinged on 87 octane fuel you will not have to worry about it pinging anymore. Ben in TN no > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 10 lines] > > jmc In my country, Chile, we only have 95 and 97 Octane gas and my 99 Dakota 3.9 L runs fine, with no engine problem! CLT. > As some of you know, I'm a 2001 Dakota owner who is currently > stationed [quoted text clipped - 13 lines] > > jmc Where did you buy it? SignatureIf at first you don't succeed, you're not cut out for skydiving > In my country, Chile, we only have 95 and 97 Octane gas and my 99 > Dakota 3.9 L runs fine, with no engine problem! [quoted text clipped - 17 lines] > > > > jmc Suddenly, without warning, TBone exclaimed (08-Jun-05 1:42 AM): > Where did you buy it? What, the truck? In the US, before we were posted here. Not California, though. jmc I was just wondering if this warning that I have read form other posters in this group was regional or covered all areas. SignatureIf at first you don't succeed, you're not cut out for skydiving > Suddenly, without warning, TBone exclaimed (08-Jun-05 1:42 AM): > > Where did you buy it? [quoted text clipped - 3 lines] > > jmc Suddenly, without warning, TBone exclaimed (09-Jun-05 6:47 PM): > I was just wondering if this warning that I have read form other posters in > this group was regional or covered all areas. Not sure, really. I purchased it overseas, it was built in Detroit, delivered to Montana, and registered in Virginia. They did ask where my residence was, so I'm guessing it meets VA emissions standards, but then so would a vehicle built to the more rigorous CA specs, right? Anyway, though some of it was over my head, I did enjoy the actually informative posts in answer to my question (could have done without the more numerous name-calling posts, but then that's usenet), though I'm still not sure if I should use the fuel or not. I think I'll probably just use it to top off, since gas coupons are for specific liter amounts, and thus rarely fill the tank, unless I'm willing to take a loss. Just so I understand, if I pump high octane fuel, it burns slower, and may cause the engine to think the mixture's too lean, and make it richer, right? Which, if I understood, could cause some sort of cycle where the mixture will rapidly cycle between too lean and too rich. It's unclear to me whether this will or won't cause knock or engine problems further down the line. I also don't know what would be the symptoms of such a cycle. I would appreciate your thoughts on this. When I buy a vehicle, I buy with the intention of keeping it 'for life', so it is important to me that I not do something now that may not show as damage until some time from now. So, thanks again, gentlemen (for the most part) for a very educational debate. Hopefully I won't start a whole new flamewar trying to get answers to these last few questions...Oh, and what is CAFE? jmc learning something new every day :) >Suddenly, without warning, TBone exclaimed (09-Jun-05 6:47 PM): >> I was just wondering if this warning that I have read form other posters in [quoted text clipped - 19 lines] >problems further down the line. I also don't know what would be the >symptoms of such a cycle. I would appreciate your thoughts on this. This cycle between too rich and too lean is actually the normal realm of operation of the emission system. All the O2 sensor can tell the computer (with the exception of a VERY few select non-chrysler vehicles) is if the mixture is too rich or too lean. Can't tell it how much too rich, or how much too lean - so it says "too rich" and the computer leans the mixture untill the sensor reports "too lean". The cycle repeats itself, and the average resultant mixture is stoich. The number of "crossings" indicates the health of the O2 sensor. >When I buy a vehicle, I buy with the intention of keeping it 'for life', >so it is important to me that I not do something now that may not show [quoted text clipped - 6 lines] >jmc >learning something new every day :) > answers to these last few questions...Oh, and what is CAFE? http://www.ita.doc.gov/td/auto/cafe.html >> answers to these last few questions...Oh, and what is CAFE? > >http://www.ita.doc.gov/td/auto/cafe.html cORPORATE aVERAGE fUEL eCONOMY >>> answers to these last few questions...Oh, and what is CAFE? >> >> http://www.ita.doc.gov/td/auto/cafe.html >> > cORPORATE aVERAGE fUEL eCONOMY If you look on your keyboard there should be a button near the "Shift" key that has "Caps Lock" written on it. Push it. ;^) If you can find a lower octane in the facinity, what about diluting it evey couple tank-fulls. >As some of you know, I'm a 2001 Dakota owner who is currently stationed >overseas. The base just upgraded the gas station, and in their infinite >wisdom, now only offer 95 Octane gas. It's fairly likely that the "87 octane" gas you can buy in the States and the "91 octane" gas you can buy in Germany (among other places) are, in fact, the SAME THING. Octane is measured two different ways; in the US it is specified and sold by the average of the two numbers, while in Europe it is often specified and sold by the higher number. See http://www.type2.com/archive/vintagebus/070415.html for more. If this is what's going on where you are, the "95 octane" available at the pump is probably about equal to "89 octane" in the States. There may be a label on the pump someplace that states how the octane is measured. If not, you might get in touch with that oil company's office in your country and ask them - someone there will know which octane number they are using. The local Chrysler dealer might know, or you might try asking Chrysler national customer service in the US. >My owner's manual says my engine could be damaged if I use high octane. >Will it really? I'm not sure. However, consider this. Most gas stations in the USA sell at least 87, 89, and 91 octane. Most people don't read the manual. Some people insist on buying 91 octane for all their vehicles. If putting 89 or 91 octane in Dakotas made the engine blow up, it would have probably made the papers by now. There will be a sticker near the gas filler that says "UNLEADED FUEL ONLY"; if it was a big problem, I would think that you'd see another sticker there says "IF YOU PUT IN GAS RATED AT OVER 87 OCTANE, YOUR ENGINE WILL SURELY EXPLODE". The fact that it _is_ in the owner's manual could probably get Chrysler off the hook for a warranty claim, but it's not good business to annoy your customers that way. Now, if you went to the airport and put 100 octane av-gas in your truck, or to the race track and put 110 octane race gas in your truck, you'd probably be right to worry. IMHO. Matt Roberds Suddenly, without warning, jmc exclaimed (07-Jun-05 5:29 PM): > As some of you know, I'm a 2001 Dakota owner who is currently stationed > overseas. The base just upgraded the gas station, and in their infinite [quoted text clipped - 10 lines] > > jmc Just a quick followup. Turns out, I shoulda paid attention to the normal octane level of UK petrol - just got back from a 6-day trip, and turns out I've been putting 95 octane in my tank every time we take a trip. Oddly, the one gas station I use locally, has low octane gas. If there's a choice of one, it's always 95 octane. So, since I've been using it on and off for a couple of years, whatever damage is already being done. After this trip, I noticed a bit of knocking. I'll put lower octane in as soon as I use some of this up. Is there any way to mitigate any damage already done? Oh, and this'll put things in perspective, the next time you folks in the US cringe at the gas pumps: 6 day trip. 1,100 miles or so. Something in the line of $300 worth of fuel. ARGH! Last trip we take the Dak on. Rest of the tour, it's the 1991 Toyota pickup for trips. >Just a quick followup. Turns out, I shoulda paid attention to the >normal octane level of UK petrol - just got back from a 6-day trip, [quoted text clipped - 6 lines] >I’ve been >using it on and off for a couple of years, whatever damage is already >being done. After this trip, I noticed a bit of knocking. I’ll >put >lower octane in as soon as I use some of this up. > >Is there any way to mitigate any damage already done? There is no damage!!! The only danger there is, is from using less octane than required not more. I do not know how in the world people ever started thinking that higher octane will damage engine. That is bizzare!!!! I suggest that you contact the manufacturer for an explanation since THEY are the ones putting this warning in the owners manual. SignatureIf at first you don't succeed, you're not cut out for skydiving > >Just a quick followup. Turns out, I shoulda paid attention to the > >normal octane level of UK petrol - just got back from a 6-day trip, [quoted text clipped - 17 lines] > ever started thinking that higher octane will damage engine. That is > bizzare!!!! >Turns out, I shoulda paid attention to the normal octane level of >UK petrol - just got back from a 6-day trip, and turns out I've been >putting 95 octane in my tank every time we take a trip. Did you see my reply? There are two ways that octane is measured, and three ways that the result of this measurement can be expressed. In the US we express it in the average of the two measurements, while continental Europe (and, I'll bet, the UK) express it as the higher of the two measurements. The odds are better than even that the "95 octane" you're buying in the UK is about the same stuff as "89 octane" in the US. Matt Roberds |
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