I put premium in the gas tank

[dan]

my friend Jason has a 2008 Chevrolet Impala with the 3900 V6, my friend Trevor has the 2006 pontiac G6 with the 3500 V6, both told me “hey dan, i put some premium gas in it, and it felt like it was faster.” i explained to them the diffrences between 87 regular and 91-93 premium and what that actually means, but both of them told me “i swear i am getting more power on premium gas…

so with gas prices as cheep as they are i decided to try it myself, so i put in some premium gas, i had a quarter of a tank, and added 20 bucks, and with premium at $2.70 a gallon her in the mitton state i wasn’t losing much in my mind, the car drive as it usually does for about 5 minutes, then after that the car did feel a little more peppy, perhaps it was because the gas was a little more fresh than the gas in the tank, but i sit and think to myself, if the PCM somehow knew that there was a higher octane fuel it could adjust ignition timing to more advanced and you might be able to get more power, but i don’t know if my car is capable of that.

just something interesting to talk about i guess.

Topic

[Jonathan Stiver]

Consider yourself lucky your engine & PCM can make use of the higher octane! My Mercedes “requires” 91 or higher, but I use 87 90% of the time and don’t notice a difference. It’s just a 4 cylinder, no supercharger or wildly high compression ratio. I suppose the timing is advanced with premium and it adds a couple hp but it’s nearly impossible to tell with only 148 hp out of a 2.2L I4. But I used to own a Mazda millenia S with the supercharged Miller cycle engine, all hell would break loose if you didn’t run 93, no joke.

[dan]

I do consider myself lucky, im so lucky that all I have to do to go slightly faster is fill up at the pump with a higher octane gas… if it was flex fuel I would try E-85 next, I bet she would really sing on that.

[Ian Williams]

[quote=”13aceofspades13″ post=121266]im sure she spark knocked quite a bit…[/quote]

Yep , it wasn’t a complete fill so it didn’t take long to get the level down enough to warrant putting premium back in .

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[Gary]

You can also get better fuel mileage if your engine can make proper use of higher octane fuel. Just thought I’d throw that in there as well.

[dan]

[quote=”Chevyman21″ post=121355]You can also get better fuel mileage if your engine can make proper use of higher octane fuel. Just thought I’d throw that in there as well.[/quote]

think it is

Shell was selling 93 octane so i put that in the fuel tank and a little more pep!

[James O’Hara]

My guess is you had some carbon build up on the valves and cylinder head and the higher octane fuel helped clean it up. My dad has always done this about once every 1-2 months and it helps keep the engine running strong. Only ever had 2 engines go bad in like 10 cars one was due to my brother going over 60mph in 2nd and keeping it floored. The other was due to simply mileage it was over the 175K mark and had been driven hard the entire time. I do it regularly with my diesel putting a cetane booster in it and it gets really peppy during and after and lasts about 2 months that way.

[Gary]

[quote=”13aceofspades13″ post=121637][quote=”Chevyman21″ post=121355]You can also get better fuel mileage if your engine can make proper use of higher octane fuel. Just thought I’d throw that in there as well.[/quote]

think it is

Shell was selling 93 octane so i put that in the fuel tank and a little more pep![/quote] I’m positive that with the computer there is a limit to how far it will increase the spark advance as well as the fuel injector dwell. Obviously, the spark advance is kept at the edge of knock due to the input from the knock sensor and if you add higher octane fuel, it will advance the spark within certain parameters. The dwell(injector on time) is dependent on how much air is coming in for the stochiometric ratio. However, you are still limited by the compression of the engine. It will get to a point where the stock compression will not allow the fuel to burn efficiently or at all as you go up in octane. Thats why diesels have massive compression and require lots of pressure and heat, because they use a cetane rating and diesel takes ALOT more to ignite and burn.

[dan]

yea i know, premiom is as high as i will go, yea i think about that, there is so far the ignition system will advance and a 9-1 compression ratio will only burn so much of a octane. thats why a lot of high performance cars run a more powerful ignition system too, a little hotter spark helps better burn higher octane fuels, luckly the ignition system in this car is strong, and probably a hair stronger than stock considering i am running MSD 8.5MM super cunductor wires.

@MDK22
don’t know how the premium fuel would have cleaned carbon off of valves or cylinder head, the only major difference between 87 and 93 octane is that 93 is more resistant too knock simply because it is harder to ignite and burns slower. maybe it would burn a little hotter which would help clean things up a little bit, i would think if anything running a higher octane fuel in a engine that is not designed to compencate for the increased octane would cause carbon build up as the fuel would not burn as completely.

[Bob]

I think Europe and U.S. use different octane rating systems; Don’t know how you do it in N.Z.

[Gary]

[quote=”13aceofspades13″ post=121710]yea i know, premiom is as high as i will go, yea i think about that, there is so far the ignition system will advance and a 9-1 compression ratio will only burn so much of a octane. thats why a lot of high performance cars run a more powerful ignition system too, a little hotter spark helps better burn higher octane fuels, luckly the ignition system in this car is strong, and probably a hair stronger than stock considering i am running MSD 8.5MM super cunductor wires.

@MDK22
don’t know how the premium fuel would have cleaned carbon off of valves or cylinder head, the only major difference between 87 and 93 octane is that 93 is more resistant too knock simply because it is harder to ignite and burns slower. maybe it would burn a little hotter which would help clean things up a little bit, i would think if anything running a higher octane fuel in a engine that is not designed to compencate for the increased octane would cause carbon build up as the fuel would not burn as completely.[/quote] Well to defend MDK’s point, usually there are different additive packages in higher octane fuels, hence you get more of the good stuff in some cases(depends where you go). Higher octane fuels can contain more cleaners and detergents etc etc. Yes higher octane does burn hotter also but this is due to the higher pressures needed to combust it(properly and efficiently I should add), when pressure(compression) rises temp also rises. This is why at a higher elevation you can run a lower octane rated fuel than you would at sea level.

[James O’Hara]

Thank you Chevyman21 I was waiting to see if anyone else was going to post why. People always try to argue with me over it but, its exactly like you stated. Higher compression means higher temps and also more outward force. Also, like you said the higher octane stuff normally has better detergents and additives so long as you are going to an actual gas station company ie Exxon, Mobil, Shell, Sunoco. If not then the detergents and additives are anyone’s guess.

With the cetane like I mentioned it increases the heat and the one I use is not just a cetane booster but, contains additives. It is super diesel additive by liqui moly. Like everything else in life everything in the proper portions is fine. DO NOT use this in anything other then a diesel engine.

[Gary]

[quote=”MDK22″ post=121784]Thank you Chevyman21 I was waiting to see if anyone else was going to post why. People always try to argue with me over it but, its exactly like you stated. Higher compression means higher temps and also more outward force. Also, like you said the higher octane stuff normally has better detergents and additives so long as you are going to an actual gas station company ie Exxon, Mobil, Shell, Sunoco. If not then the detergents and additives are anyone’s guess.

With the cetane like I mentioned it increases the heat and the one I use is not just a cetane booster but, contains additives. It is super diesel additive by liqui moly. Like everything else in life everything in the proper portions is fine. DO NOT use this in anything other then a diesel engine.[/quote] Thank you my friend, and yes Diesel needs cetane otherwise you will do serious damage. The compression in a diesel is much more than a typical gas engine with compression ratios such as 20:1(diesel) vs 9:1(gasoline). Gasoline will spark too soon in the Diesel Cycle and it WILL cause damage. Diesels make immense amounts of heat and even need glow plugs or an incoming air heater to even get started. Diesel is much less volatile than gasoline. On the other side of the coin, diesel won’t even burn in a gas engine because it doesn’t have enough pressure to combust. I think of cetane as a “super high octane” personally. However cetane is rated the opposite of octane, the higher the cetane rating, the easier it is to burn as lower cetane rating is harder to burn. As a big rig tech I know you know this MDK, but I’m stating it for others 🙂

[dan]

it is a possibility that the premium gasolines have better detergents in them as well, it is also possible since my ignition system is making advances, and that it is possible the higher octane fuel burns hotter that it is possibly helping clean out any carbon, but I personally still think the fact the ignition system advanced has to do more with what performance increases I may be feeling than any carbon clean up.

and yes Diesel burns considerably slower than Gasoline, much slower, in fact here is a interesting video on that and other fuels including grade A Jet, kerosene, fuel oil, and 110 low lead AV Gasoline.

[Gary]

[quote=”13aceofspades13″ post=121837]it is a possibility that the premium gasolines have better detergents in them as well, it is also possible since my ignition system is making advances, and that it is possible the higher octane fuel burns hotter that it is possibly helping clean out any carbon, but I personally still think the fact the ignition system advanced has to do more with what performance increases I may be feeling than any carbon clean up.

and yes Diesel burns considerably slower than Gasoline, much slower, in fact here is a interesting video on that and other fuels including grade A Jet, kerosene, fuel oil, and 110 low lead AV Gasoline.
https://www.youtube.com/watch?v=7nL10C7FSbE%5B/quote%5D Agreed, I’m sure it has more to do with the spark advance than any carbon build-up, but every little bit helps!

[Ian Williams]

[quote=”DBFSubs21!” post=121729]I think Europe and U.S. use different octane rating systems; Don’t know how you do it in N.Z.[/quote]

The higher octane fuels we get come from Australia , with some stations blending their own locally

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