Gas Question
nope.
Higher gas is actually good for the car, lowers knocking and its more efficient. I don't think you'll see significant numbers in increasing 89+ gas. From time to time i put 89 in her, just for ****s and giggles, but i dont see anything vastly improved.
Higher gas is actually good for the car, lowers knocking and its more efficient. I don't think you'll see significant numbers in increasing 89+ gas. From time to time i put 89 in her, just for ****s and giggles, but i dont see anything vastly improved.
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From: Lodi, California
Originally Posted by Arithmetic
nope.
Higher gas is actually good for the car, lowers knocking and its more efficient. I don't think you'll see significant numbers in increasing 89+ gas. From time to time i put 89 in her, just for ****s and giggles, but i dont see anything vastly improved.
Higher gas is actually good for the car, lowers knocking and its more efficient. I don't think you'll see significant numbers in increasing 89+ gas. From time to time i put 89 in her, just for ****s and giggles, but i dont see anything vastly improved.
higher octane is BAD! It will result in incomplete combustion, which leaves promotes carbon buildup in the cylinders and exhaust, will get between the valves and valve seats and can foul injectors. I'm not just talking out my *** here, either. A coworker had to have her injectors replaced because she always ran 92 thinking that was the best thing she could do for her car- until it stopped running. Even her mechanic told her to go back to 87, and recommended a valve lapping to polish away the carbon buildup that was giving her some small pressure leaks... but that would have cost more than her car was worth.
You'd know if you had true knock. You'd probably crap yourself if you heard it while driving. It's kind of like that noise your car makes when you don't clutch properly and you stall the car when you're creeping into your parking space- or if you shift from 1 to 3 going up a hill and your engine bogs and sounds like it's gonna die. If you're hearing a clicking sound it's probably just the lifters clicking like all lancers have- it's been identified and diagnosed as not a problem and there's nothing we can do about it.
You'd know if you had true knock. You'd probably crap yourself if you heard it while driving. It's kind of like that noise your car makes when you don't clutch properly and you stall the car when you're creeping into your parking space- or if you shift from 1 to 3 going up a hill and your engine bogs and sounds like it's gonna die. If you're hearing a clicking sound it's probably just the lifters clicking like all lancers have- it's been identified and diagnosed as not a problem and there's nothing we can do about it.
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From: Lodi, California
Originally Posted by engineerboy
higher octane is BAD! It will result in incomplete combustion, which leaves promotes carbon buildup in the cylinders and exhaust, will get between the valves and valve seats and can foul injectors. I'm not just talking out my *** here, either. A coworker had to have her injectors replaced because she always ran 92 thinking that was the best thing she could do for her car- until it stopped running. Even her mechanic told her to go back to 87, and recommended a valve lapping to polish away the carbon buildup that was giving her some small pressure leaks... but that would have cost more than her car was worth.
You'd know if you had true knock. You'd probably crap yourself if you heard it while driving. It's kind of like that noise your car makes when you don't clutch properly and you stall the car when you're creeping into your parking space- or if you shift from 1 to 3 going up a hill and your engine bogs and sounds like it's gonna die. If you're hearing a clicking sound it's probably just the lifters clicking like all lancers have- it's been identified and diagnosed as not a problem and there's nothing we can do about it.
Originally Posted by engineerboy
higher octane is BAD! It will result in incomplete combustion, which leaves promotes carbon buildup in the cylinders and exhaust, will get between the valves and valve seats and can foul injectors. I'm not just talking out my *** here, either. A coworker had to have her injectors replaced because she always ran 92 thinking that was the best thing she could do for her car- until it stopped running. Even her mechanic told her to go back to 87, and recommended a valve lapping to polish away the carbon buildup that was giving her some small pressure leaks... but that would have cost more than her car was worth.
Exactly what I was trying to think of nice post should really be a sticky because lots of people use higher octane than 87.
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From: Lodi, California
Originally Posted by otter
Nope, higher octane just increases the flash point of the gas. Higher octane means the gas can handle more pressure and heat before it combusts.
Higher octane is a waste of money. Just use what your car is made for which is regular unleaded. If you do go from 87 to 92 and then switch back after a few months your engine will start to knock. dont upgrade and then downgrade, you will just be screwing yourself up. And also dont add any of those crap fuel accelerators casue they dont work for anything.
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From: Lakewood, CA
Using a higher octane fuel will sometimes smooth out an older engine at idle, however it is just a waste on a new one. Only reason to upgrade would be a significant change in ignition timing, or cylinder pressue (like a turbo/supercharger.)
you won't knock if you go back to 87 if your engine is in proper working order. You'll be fine.
Otter is right- octane just increases the fuel's resistance to detonation.... or another way to think of it is this. The fuel enters the combustion chamber via the injectors as a fine mist that's travelling down into the cylinder. The spark ignites that fuel and creates a flame that's moving down the cylinder- that's called the flame front. A spectacular video of this is found in the opening of GT3 when they're doing the internals of the TOM's JGTC car.
Fuel that's matched for the compression will have a nice "slow" flame front and will- in theory only- fully combust, and will allow the pistons to complete their full travel un-interrupted. The speed of the flame front is controlled by the compression in the cylinder and the octane. If the octane is too low, the flame front moves down the cylinder too quickly- and that explosion interrupts the travel of another piston.... this is what we call "detonation" or "knock". This is bad. This happens when you run 87 octane in a higher compression engine; turbo, or hi-comp pistons, for example. To prevent knock, you run higher octane- which slows the flame front, slows the explosion and allows all of the pistons to complete all of their revolutions wihtout interruption.
So if we take a higher octane fuel (it's resists burning at low compression, like in our lancer engine's 9.5:1 CR) and try to burn it what happens? It doesn't fully combust because we didn't compress it enough, so we have unburnt fuel in the cylinder that's now a gas. This gas is exhaust- the same crap coming out of your neighbor's car in the morning that makes his bumper all black- or that Civic that's running too rich and leaves a smoke trail every time he shifts. Now that exhaust is sticking to the walls of your cylinders and the top of your valve seats, and possible being backed up into your intake manifold. Yes, back into your intake manifold. My spare lancer engine's IM has carbon buildup in the runners. The pistos will scrape most of it out of the cylinders- to the detriment of your oil's crap-carrying-capacity. But your helpless valves can only let it build up, and your poor plugs and injectors, too. Take a look at your plugs the next time you change them and notice all the carbon buildup. It gets worse if you go to high octane fuel... but that carbon buildup is all over the inside of your engine.
This is potentially YOUR engine on high octane fuel for too long (pic 1)
http://www.miata.net/hakuna/port2.html
Ok, I'm done for the night
Otter is right- octane just increases the fuel's resistance to detonation.... or another way to think of it is this. The fuel enters the combustion chamber via the injectors as a fine mist that's travelling down into the cylinder. The spark ignites that fuel and creates a flame that's moving down the cylinder- that's called the flame front. A spectacular video of this is found in the opening of GT3 when they're doing the internals of the TOM's JGTC car.
Fuel that's matched for the compression will have a nice "slow" flame front and will- in theory only- fully combust, and will allow the pistons to complete their full travel un-interrupted. The speed of the flame front is controlled by the compression in the cylinder and the octane. If the octane is too low, the flame front moves down the cylinder too quickly- and that explosion interrupts the travel of another piston.... this is what we call "detonation" or "knock". This is bad. This happens when you run 87 octane in a higher compression engine; turbo, or hi-comp pistons, for example. To prevent knock, you run higher octane- which slows the flame front, slows the explosion and allows all of the pistons to complete all of their revolutions wihtout interruption.
So if we take a higher octane fuel (it's resists burning at low compression, like in our lancer engine's 9.5:1 CR) and try to burn it what happens? It doesn't fully combust because we didn't compress it enough, so we have unburnt fuel in the cylinder that's now a gas. This gas is exhaust- the same crap coming out of your neighbor's car in the morning that makes his bumper all black- or that Civic that's running too rich and leaves a smoke trail every time he shifts. Now that exhaust is sticking to the walls of your cylinders and the top of your valve seats, and possible being backed up into your intake manifold. Yes, back into your intake manifold. My spare lancer engine's IM has carbon buildup in the runners. The pistos will scrape most of it out of the cylinders- to the detriment of your oil's crap-carrying-capacity. But your helpless valves can only let it build up, and your poor plugs and injectors, too. Take a look at your plugs the next time you change them and notice all the carbon buildup. It gets worse if you go to high octane fuel... but that carbon buildup is all over the inside of your engine.
This is potentially YOUR engine on high octane fuel for too long (pic 1)
http://www.miata.net/hakuna/port2.html
Ok, I'm done for the night
Last edited by engineerboy; Nov 7, 2004 at 12:32 AM.
Originally Posted by turbonutter
Using a higher octane fuel will sometimes smooth out an older engine at idle, however it is just a waste on a new one. Only reason to upgrade would be a significant change in ignition timing, or cylinder pressue (like a turbo/supercharger.)
Amen. Your engine is only tuned for 87 Octane, so be grateful you can save yourself $0.20 cents a gallon!
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From: A
Originally Posted by turbonutter
Using a higher octane fuel will sometimes smooth out an older engine at idle, however it is just a waste on a new one. Only reason to upgrade would be a significant change in ignition timing, or cylinder pressue (like a turbo/supercharger.)