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anyone using premium gas ?

1M views 2K replies 423 participants last post by  paulrondelli 
#1 ·
yes or not worth it
 
#256 ·
Octane is for antiknock, if its not knocking whay do you need more. Here is something else that I learned a a training school. Ocatne makes fuel more stable to prevent autoignition, meaning ignition from a source other than the spark plug like a hot piece of carbon. Too much octane can actually cause an adverse effect by making fuel harder to ignite reducing performance. I have tried it with absolutly no effect in my 2.0 zetec. Dont assume what people know or have tried.
 
#257 ·
I fueled up this morning and the cost difference between regular and premium (v-power at shell) was $0.28. Even a 12 gallon, bone dry fill is only $3.36 increase. Is that seriously so much out of someone's wallet?

Some people need to get out of the past and move into the current world of technology. I am the first to admit that I don't see enough of a benefit in my Nissan Armada to use premium in that vehicle. It doesn't give me the additional gas mileage nor do I need more power. Did I try it? Yes. That way, I would know 100% whether it worked for me or not.

But the GDI engine in our Foci is more sophisticated. For $3.36 a tank and 3 tanks ($10.08, and approx 1000 miles worth of driving), you will understand. Save up the cash this month and use it next month if you have to. Then, when you see that your car is running/idling better and is getting better fuel economy, good job!

Or just continue to believe that the gas companies are out to ruin you and use regular.
 
#264 ·
You, sir, are a troll. You just don't get it.

Go ahead and get your post numbers up. Start an argument wherever you please. Obviously, all of us who are trying to help the Focus Community by reporting our positive results are all wrong and simply trying to get you to waste all of your precious income.

[nutkick]
 
#270 ·
Look, I apologize. I'm not trying to be a pr1ck. Seriously.

I'm just saying that I didn't believe it until I tried it. If I was asking you to spend $1000 on something, I would understand the severe skepticism. But for three tanks of gas and a mere $10...

Maybe someday you'll try it, maybe not. I respect that you have an opinion and are enough of an enthusiast to be on these forums. Best wishes.[cheers]
 
#279 ·
The main discussion here is an 87 octane engine being run on higher octane, and if ther would be an advantage. Like I said in my previous post, you cant trust 87 octane to be 87 octane. It could be 65. Known for a fact to be true at times. If you run poor quality fuel and switch to 93 you would probably notice a difference. They did not talk about at school the requirments of specific engines, just that if they are not knocking they dont need more octane. One thing that concerns me about this discussion is that everyone says that efi can adjust for knock from low octane, but at what cost. If timing must suffer for no knock then performance should too. But this is not even what the whole discussion has been about, it is extra octane, is there a benefit.
 
#283 ·
Well that's kinda the point here




You're kind of flailing now. [facepalm] The engine has quite a high compression ratio and adjusts ignition timing and other variables according to the spark knock detection. High octane or premium gasoline will definitely allow it to adjust itself to run better than on regular gasoline. Whether it's worth it or not is another subject.
 
#286 ·
My [:)][:)][:)][:)][:)][:)]g god

The whiners aren't those that have used 91/93 or higher and seen benefits

The whiners are those that haven't and can't understand our perspective.

We've proven that premium fuels in GDI engines improved performance, especially with our higher 12:1 ratio.

You morons now do us a favor and dog up facts to back up your statements instead of just throwing out useless statements about how premium is a waste of money.
 
#287 ·
I have an example...from first hand experience, how premium may be able to save fuel.
On my way home from work every day, there is a long, fairly steep hill with a 30 mph speed limit. When running 87 octane, without fail, the car would downshift, rpm's go up, and I would lose .5-.7 mpg on the dash display by the time I reached the top...Now, running 92 octane, I can pull the hill without the car downshifting, and only lose .2-.4 mpg to the top. My assumption is that under a heavier load, the premium fuel does not knock, timing is more advanced, more power is being generated, and the transmission doesn't need to kick down.
Not scientific, nor is it huge savings, but it is an example.
 
#289 ·
After running 4 tanks or 89 octane .... i went back to 87 for a test tank.
I lost 2 mpg and the car is definetly less responsive.

Debate all you want ... the best way is to test it for yourself to see if it will do any good for YOU.

For me ... i will be using 89 octane from now on.

We have a 12.4 gal tank, with a difference of 10 cents a gal ... it will cost you a max of a $1.24 to check it for yourself!!
 
#294 ·
I'm wondering why people are taking everything in the owner's manual as absolute proof of its existence?
If you're speaking of the blurb that mentions better performance with higher octane, I don't think most of us are considering that being absolute proof. If you take your time and actually read this thread, there aren't many posts that even mention that verbage. I don't think the thread would have reached 14 pages if there were many members who took it as absolute proof.

Many of us are knowledgeable of the technologies Ford is employing in these engines, and inferring from that. Others have shown that they are seeing positive results from using higher octane fuel.
 
#295 ·
If the 12:1 engine is designed to be an 87 octane engine, it should run on 87 octane fine. I believe the answer to this whole thing is as follows. The person that stated what the owners manual said has the key. The owners manual basically said that 87 octane was ok but you may experience knocking. if you do experience koncking, use a higher grade of fuel. They are basically saying in a nice round about way that the engine is designed to run on premium but you can get away with using 87 but may have performance issues. Performance issues usually equate to a loss in fuel milage.
Of course this particular engine will run better on premuin fuel,even the manufacturer is saying so.The basis of the discussion is to take an engine designed to run specifically on 87 and see if it gets better milage, not just this one specific case.The manufacturer is not going to market the 2012 focus by saying you must run 93 octane,when gas is $4 a gallon, or nobody no one will want it but car enthusiasts like you guys. It is competely obvious that you are seeing results because the manufactuer says you will right in the owners manual. I thought you guys were trying to extend this concept to other setups like my 2.0 zetec, which I am certain does not get better milage on premium,because I have tried it. I think that those engine managment strategies you talk about,advancing timing until it knocks and backing off timing, if so, is a design reason why premium is required for optimum performance, not to prevent detonation and pinging which is from an autoignition event caused by excessive compression, or a hot spot in the combustion chamber, which is the textbook definition of knock. If you design the engine to spark at the verge of too early it seems obvious by design it will need higher octane fuel. Thats all I have to say about that.
 
#297 ·
The owners manual basically said that 87 octane was ok but you may experience knocking. if you do experience koncking, use a higher grade of fuel.
That's not what my owner's manual says.

 
#296 ·
I think the point here is the 12:1 engine is designed to run optimally with premium gas but the ability to control virtually everything permits the car to run, sub-optimally, on 87 octane gas. In the days before the electronic controls now common in cars you could not run a 12:1 compression engine on 87 octane -- PERIOD! If you tried to it would knock badly enough to eventually break something.

Being able to control:

1. Ignition timing

2. Valve timing

3. Fuel delivery

among other things gives the engine the ability to run outside of the normal required octane rating. But, because it has a 12:1 compression ratio, the engine can be more efficient when running the fuel it prefers -- premium...


Brian
 
#302 ·
This thread is the reason I drink.

I averaged 43mpg on my 65 mile commute to work this morning with 92 octane gas. You keep doing your thing, I'll keep doing mine.
 
#305 ·
What does "improved" performance mean? Is it quicker to 60mph,1/4 mile time quicker? Or is it a little improved acceleration? Would this better performance show up if I took it to the strip with say regular then premium?
 
#315 ·


You could also interpret the premium fuel blurb to apply to knocking or poor performance at high altitude, admonishing to use premium fuel in those conditions.

I'm not trying to start another f'ing war here, it is just my interpretation of the words.

I'll certainly try premium on mine next few fillsup, just out of curiosity, but the manual seems sufficiently vague to extract multiple meanings from its structure, in this particular dialogue box, for some people.

Sometimes, you have to read between the lines...and not take sentences out of context.
 
#316 ·
You could also interpret the premium fuel blurb to apply to knocking at high altitude, admonishing to use premium fuel in those conditions.
I had the same thought, that it could be interpreted that way.
 
#317 ·


After 3 tanks of 91 Vpower this is where I was this morning, you can see I still had some left (indicated range left was 80). This is actually a bit higher then normal since I did a lot of highway driving, my average usually falls in the 600 or so range. All I know is I am getting at least enough of a increase that I filled up with 91 again today and I'll have another go at it.
 
#318 ·
I thought of the answer you are prodding me for. On the 12:1 duratec engine im sure if you do the math with bore and stroke and combustion chamber volume you get 12:1.
But If I were an engineer,which I am, and I wanted to make an engine with a variable dynamic compression ratio, I would use variable valve timing to effectivly shorten the intake stroke by having the intake valve open for less time,which would effectivly shorten the compression stroke and reduce the comression ratio. I would then design engine managment strategies to utilize this function. Like an antiknock strategy that if the engine knocks the compression ratio could be reduced. I didnt design the duratec but I have a very strong suspicion that your 12:1 would never be 12:1 when running on 87 octane. So to answer your question again on how much octane does it take for a 12:1 engine, whatever it is designed to take.
 
#321 ·
It may well be the case that limiting the inflow of air effectively lowers the compression ratio so that the engine can run 87 octane, but that's kind of what we've been saying all along -- that the modern car that is able to control almost everything is able to run, albeit with lower performance, outside of the preferred operating range. And, to get maximum performance, you need to run gas with sufficient octane so that the engine doesn't have to be hobbled by those same performance lowering adjustments.

Before the advent of these newer control capabilities a 12:1 compression ratio engine would require every bit of 93 octane and probably prefer even higher octane. That, to me, is the intrinsic octane goal for a 12:1 compression ratio engine and, I would suspect the use of even higher octane gas, such as racing gas, would see still further improvement in max HP and mpg over the typical max octane of 91. Some places the standard max is 93 octane but many/most places it's 91. I' like to know what the minimum octane a 12:1 engine would need to see maximum performance and mpg -- I don't know for sure what that is but suspect it's around about 95...


Brian
 
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