LordJim Posted February 20, 2007 Share Posted February 20, 2007 I've heard that premium actually has less energy than regular.Less energy in 'stock' form, perhaps. But premium is better able to stand up to high compression ratios therefore leading to more power. At least that's how I think it works. Someone, no doubt, will step in and correct me if I'm mistaken. It is, after all, the way of the innertubes. - Jim Link to comment Share on other sites More sharing options...
SLegacy99 Posted February 20, 2007 Share Posted February 20, 2007 I am thankful that Subaru refined the N/A engine so that it would run on 87 octane. However, my '96 required 89 and anything less the car didnt run well. So to me this just says its retarted if you have a new LGT and are too cheap to run at least 89 octane, I mean come on. I know there are alot of cars on the road that say they need 91 or higher and really dont, but the turbocharged LGT isnt one of them. He will pay for it later. Link to comment Share on other sites More sharing options...
showbo Posted February 20, 2007 Share Posted February 20, 2007 He should have just purchased a 2.5i..... It's kinda like the guy I saw pumping 87 oct in his brand new 07 Vette this past saturday. Sure it can be done, but why buy a performance car? Because that guy has the money to afford it, and doesn't care about performance at all, just wants the status with the new vette. I remember a friend made a comment like...Look at that Viper...man i bet that guy gets crappy gas mileage. I told him, that guy spent 90k on that car, im sure his last worry is gas mileage. Oscar Link to comment Share on other sites More sharing options...
pillboy Posted February 20, 2007 Share Posted February 20, 2007 I think all the gas comes out of one underground tank at each station...makes no difference what button you push on the pump. It is still ugly. Link to comment Share on other sites More sharing options...
Prime Power Posted February 20, 2007 Share Posted February 20, 2007 It did cause the injectors to fail as there was a build up of something that did not burn off. Link to comment Share on other sites More sharing options...
IwannaSportSedan Posted February 20, 2007 Share Posted February 20, 2007 Slightly off topic but, I've heard that premium actually has less energy than regular. Point being that if your car runs fine on 87 you aren't gaining anything by using premium... if you are describing an engine designed and tuned for regular unleaded, with a normal compression ratio (probably around 10:1) that is somewhat true. It is harder to burn higher octane fuel, and that engine will have a hard time burning it completely to gain as much power as "easier to burn" low-octane gas. it doesn't run as hot, and it doesn't have as much cylinder pressure to burn that high octane fuel, and the unburned fuel tells the oxygen sensor that the mixture is rich (even if it technically is the right ratio when it goes in) and the engine runs leaner than normal. However. With a high static compression ratio (sometimes referred to as high specific output) engine (above about 11:1), or a turbocharged or supercharged engine that has dynamic compression (the forced air crams more volume into the space than the engine would draw normally) the conditions change somewhat. Under higher-demand engines, they can burn the higher octane fuel more completely under higher pressures and temperatures in the cylinders. The detonation resistance is required so that those higher pressures and temperatures don't detonate the fuel too early, and waste it's energy in the intake tract, and potentially cause damage to the engine parts. Exploding vaporized gasoline isn't a trifle, afterall, and needs to be controlled. When the fuel is burned up in the intake tract, the engine has much less fuel to burn in the cylinder after that happens, and power is lost, and damage is done, sometimes before the engine management can compensate with more fuel, which then runs rich, or continues do pre-detonate. The computer can then also dial back ignition timing, and turbo or supercharger output, and run at a lower fraction of it's potential. If one were to drive a turbocharged car like a maniac, with low octane fuel, the engine computer may not be able to reconcile between the throttle inputs, and engine load due to gear selection, versus trying to "tune down" the engine to avoid detonation (knock or ping, or whatever people choose to call it) The engine likely will pre-detonate it's fuel until it goes "pop". Possibly permanently. even if you drive nicely, there is still the potential for low octane fuel to detonate in a hot engine. So you might get lucky, and the car will be ok, or it could still cause gradual and less severe damage, but damage, nonetheless. And on the gas station note, they probably have one big tank PER FUEL GRADE. Or they mix in ingredients before the fuel is delivered through the nozzle. Otherwise they would be mixing ethanol, and premium additive packages with all the fuel, and they would have the same fuel coming out of every pump, and would have to disclose that on the pump labels, that all of the options are the same ethanol content and the same octane. That would be fraud, and against the law, otherwise. Maybe they add the octane booster, and detergent packages, and even ethanol addative between a single supply tank, and the different pump nozzles, but how does that negate the need to use the proper fuel grade? You still get different fuel grades out of different nozzles, and Legacy GTs with turbos require a higher minimum octane than most, for reasons that are illustrated. Link to comment Share on other sites More sharing options...
mccorry Posted February 21, 2007 Share Posted February 21, 2007 I've run 89 and 91 oct. in my LGT on occasion... no pinging or knock detected while datalogging. I don't think I'd try it in the summer, though.... Link to comment Share on other sites More sharing options...
coxx Posted February 21, 2007 Share Posted February 21, 2007 I think all the gas comes out of one underground tank at each station...makes no difference what button you push on the pump. :lol: then what's the isomersation facility at the refinery for? "Barack Obama, mothaf#%@a! Barack Obama! I'm the president...of hittin' the ass!" -this is not a political view it's merely a quote from a hilarious tv show. Link to comment Share on other sites More sharing options...
fweasel Posted February 21, 2007 Share Posted February 21, 2007 :lol: then what's the isomersation facility at the refinery for? You put your weed in it:icon_mrgr ignore him, he'll go away. Link to comment Share on other sites More sharing options...
edkwon Posted February 21, 2007 Share Posted February 21, 2007 Tell him its his funeral but if he wants to go against common sense, unfortunately thats his perogative. I only hope it incurs some serious engine/fuel system damage eventually so he'll maybe realize his mistake. I bet he likes to smoke, drink and live unhealthy too cause 'he feels fine now'. Ed Link to comment Share on other sites More sharing options...
mccorry Posted February 22, 2007 Share Posted February 22, 2007 ^^^^^^^^ Don't be a jerk. Wishing bad luck and engine problems on someone is not cool. Link to comment Share on other sites More sharing options...
imstillatwork Posted February 22, 2007 Share Posted February 22, 2007 Under most normal driving conditions lower octane will be fine. Your manual even says so - its ok to use if 'premium' is not available. Under heavy load or higher temps, pre-detonation is more likely to occur - not guaranteed to occur. the average driver could get away with 87 in a LGT easily. Racer Boy might, in extreme conditions, get some pre-detonation that is out of the range of the anti-knock sensors / ecu to fix by fuel trim / ignition timing. stock car, of course. You could run 87 in high compression engines also, but you'd have to retard the timing so far that you'd not benefit from the high compression in the first place... Saying that the manufacture suggests it, so it IS the ONLY option is wrong. The manufacture suggests it because it covers ALL situations by a WIDER MARGIN. Link to comment Share on other sites More sharing options...
VTsullyman Posted February 22, 2007 Share Posted February 22, 2007 ^^^^^^^^ Don't be a jerk. Wishing bad luck and engine problems on someone is not cool. Yeah well at the same time if some damage does occur i hope it happens to him and not the next guy down the line, ya know? 2007 DGM LGT 2003 Suzuki SV650S Link to comment Share on other sites More sharing options...
TRAC3 Posted February 22, 2007 Author Share Posted February 22, 2007 Yeah well at the same time if some damage does occur i hope it happens to him and not the next guy down the line, ya know? yeah, still not cool.... never wish harm upon anyone or their vehicles, it's just bad Karma... yes, he or his wife should be using premium, they know the benefits of the higher octane fuel... they're not trying to save money, or cheat the system, they just have not seen any detriment thus far. they will more than likely switch over after I tell them all this info.. trust me they know the benefits and reasoning of better fuels, so no knocking them for their intelligence and whatnot Link to comment Share on other sites More sharing options...
edkwon Posted February 22, 2007 Share Posted February 22, 2007 I dont have much sympathy for ppl who make wrong decisions despite being adequately informed, anyways, the moral/karmic pluses and minuses of wishing misfortune upon someone is not the point of this thread, so lets not be distracted. Ed Link to comment Share on other sites More sharing options...
mccorry Posted February 22, 2007 Share Posted February 22, 2007 ^^^^^^^^^^^ Point is that you said it... which I think is uncool. I have datalogged lower octane fuel out of curiosity and I could run it in winter with NO KNOCK or -Kc. What facts are you using, Ed? Is it easy to spout off about things you know nothing about? Link to comment Share on other sites More sharing options...
edkwon Posted February 22, 2007 Share Posted February 22, 2007 ^^^^^^^^^^^ Point is that you said it... which I think is uncool. I have datalogged lower octane fuel out of curiosity and I could run it in winter with NO KNOCK or -Kc. What facts are you using, Ed? Is it easy to spout off about things you know nothing about? If that is true with the data you've accumulated, why are you not correcting every respondant in the thread who feel that running less than 91 octane is a bad idea for the turbo engine? why choose at this point to reveal this info instead of early on in the thread so then ppl may learn something? Link to comment Share on other sites More sharing options...
mccorry Posted February 22, 2007 Share Posted February 22, 2007 If that is true with the data you've accumulated, why are you not correcting every respondant in the thread who feel that running less than 91 octane is a bad idea for the turbo engine? why choose at this point to reveal this info instead of early on in the thread so then ppl may learn something? See post #32. Link to comment Share on other sites More sharing options...
edkwon Posted February 22, 2007 Share Posted February 22, 2007 See post #32. I saw that, you yourself say its not a good idea to try under hot summer conditions, i already read that before i posted my criticism, but anyways that is completely besides the point, ppl make critical nonspecific comments all the time on internet forums, why would you think my random comment is serious and im truly wishing ill will on complete strangers i dont even know? you know its not even worth the response. Link to comment Share on other sites More sharing options...
mccorry Posted February 22, 2007 Share Posted February 22, 2007 Oh well... Hey... run whatever gas you want to... but don't be nasty to other people for simply stating their opinion. Link to comment Share on other sites More sharing options...
SWP-LegacyGT Posted February 22, 2007 Share Posted February 22, 2007 Jesus F'ning Cripes mccorry, chill if someone has a "different" opinion that is "negative" about someone's car. Notice that the OP states with this entire thread "my buddy...." This of course is all based on what the OP knows from his "buddy" told him he's done. either way, cool or uncool, they are going to voice what most of us think of running 87 in a Turbo'ed car so just don't be going on a crusade to "purify" their comments. Datalogging or not, running a lower grade octane below what the manual states to run is again, not smart. Link to comment Share on other sites More sharing options...
mccorry Posted February 22, 2007 Share Posted February 22, 2007 Point taken. I might be out of line here. If so, then sorry... I'm out of this one. Link to comment Share on other sites More sharing options...
meier motor sports Posted February 22, 2007 Share Posted February 22, 2007 my dad bought a vibe gt (takes premium) he read in the owners manual about if 91 is not avalible you can try 87 and if you dont have any issues then.... there ya go. i didnt read it so im not 100% on what it said. but if you ask me thats lame to buy a gt or any performance car and cheep out on the gas. just like going to pepboys or similar to get new rubber for your tires on a performance car. tisk tisk Link to comment Share on other sites More sharing options...
IwannaSportSedan Posted February 22, 2007 Share Posted February 22, 2007 The Vibe GT is not turbocharged, IIRC, just a high-specific-output engine. HO engines are sensitive to octane somewhat due to the higher compression and heat, forced induction is more sensitive, due to the intake pressure added to that mix. Engines can, to some extent, run on any gas or thin fuel that burns somewhat normally, that doesn't mean that it is ideal, and it is a matter of degree. Running lower octane in a pinch will get you to the next gas station, perhaps even through a full tank of gas, if there is nothing else available. It also should infer that you should take it easy, and not to lug or overstress the engine, to avoid predetonation and it's possible damage. That is not the same as trying to save a dollar or two by not following reasonable requirements, and filling with low octane fuel on a regular basis, and driving the car normally and long term. One is a temporary stop gap, the other is willful ignorance of reasonable recommendations. Link to comment Share on other sites More sharing options...
imstillatwork Posted February 22, 2007 Share Posted February 22, 2007 my dad bought a vibe gt (takes premium) he read in the owners manual about if 91 is not avalible you can try 87 and if you dont have any issues then.... there ya go. The 07 GT manual says the same..... a little 87 is not the end of the world people.... Link to comment Share on other sites More sharing options...
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