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We have 22 refineries here in California. I ran one tank of premium through, and, although I thought is smoothed out my tranny's slight start-from-stop shudder, I didn't notice a difference in anything else - but I don't flog it anyway. I'm back to regular and I don't even notice any difference in the shifting.[sleep]
Actually California only has 20 refineries, but then who is counting......

I went and read the owners manual and it recommends using 87 Octane Regular Unleaded gas. To me it makes absolutely no sense to use anything other than Regular Unleaded. By using Premium you are gaining nothing other than spending more money for something that the engine has to compensate (de-tune) for. If you think Premium Unleaded gas has anything more in it than Regular Unleaded (other than more Octane) then you have bought into the gas companies hype.

I will agree that there is a difference between brands, but no difference between any one brands Regular gas versus their Premium gas other than the octane rating.
 

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...By using Premium you are gaining nothing other than spending more money for something that the engine has to compensate (de-tune) for...
You're reducing the chance that your timing is going to retard. It is a twin independent variable camshaft timing engine. I'm sure the horsepower and torque is rated when the timing is most advanced.

I will agree that there is a difference between brands, but no difference between any one brands Regular gas versus their Premium gas other than the octane rating.
You're making it sound like octane rating is only a number.
 

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You're reducing the chance that your timing is going to retard. It is a twin independent variable camshaft timing engine. I'm sure the horsepower and torque is rated when the timing is most advanced.



You're making it sound like octane rating is only a number.
As long as you use a quality 87, your timing won't retard. There's another thread floating around here where someone got a response directly from a Ford technician that stated that the timing won't advance with a higher octane fuel. I wish someone would do a dyno run with regular and premium so we can put this all to rest. I'm guessing you will see a 2-3 hp gain at most, and that will be on the upper end of the RPM's that most people will never access anyways.
 

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Here's the bottom line.... Unless your engine is specifically desinged to run on 93 octane fuel (and the Focus clearly isn't) you are doing nothing but wasting your money by buying it! You can argue all you want but the facts are the facts!
 

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Here's the bottom line.... Unless your engine is specifically desinged to run on 93 octane fuel (and the Focus clearly isn't) you are doing nothing but wasting your money by buying it! You can argue all you want but the facts are the facts!
93 Octane - probably a waste.

But I already argued about this in another thread for days. The Focus will most likely benefit from higher octane in hot climates. The Cruze was tested in Death Valley and they found that it did better with 91 octane and was worth the extra $0.12 per gallon. (I understand the Cruze is not the Focus, but I'm sure they work the same.)

http://blogs.insideline.com/roadtests/2011/09/2011-chevrolet-cruze-ltz-the-ultimate-hot-weather-mpg-test---regular-vs-premium.html
 

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You're reducing the chance that your timing is going to retard. It is a twin independent variable camshaft timing engine. I'm sure the horsepower and torque is rated when the timing is most advanced.
Ignition timing and cam timing are two different things.

Variable cam timing allows the overall characteristics of the engine to be changed on the fly. In general advancing when the intake valves open will enhance power in the lower rpms and retarding the when the intakes closes enhances power in the upper rpm range. The variable valve timing allows the engine to have a broad power range.

Ignition timing is when the spark is created and needs to happen at the right point to ensure max cylinder pressure occurs at the right point after TDC. In general for max power the timing needs to advance with rpm. The knock sensor will retard the ignition timing if it detects detonation.
 

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Actually California only has 20 refineries, but then who is counting......

I went and read the owners manual and it recommends using 87 Octane Regular Unleaded gas. To me it makes absolutely no sense to use anything other than Regular Unleaded. By using Premium you are gaining nothing other than spending more money for something that the engine has to compensate (de-tune) for. If you think Premium Unleaded gas has anything more in it than Regular Unleaded (other than more Octane) then you have bought into the gas companies hype.

I will agree that there is a difference between brands, but no difference between any one brands Regular gas versus their Premium gas other than the octane rating.
The manual also states that running premium will result in increase performance.

Most engines are tuned with high and low ignition tables. Which if is true for the Focus it would make sense why they recommend regular but also state that premium will increase performance(Page 354 "Octane recommendations" last sentence in the owners manual.). One day I'll hook it up to my Dash Hawk and try and figure it out.

My G8's had high and low octane tables and running on the low octane table the car made around 8HP less than the high octane table (Stock). It switched to the low octane table when it detected a predetermined knock count withing a set time frame. It was kind of a PITA when trying to tune the thing because it was pretty sensitive and switch over when it wasn't needed. I ended up just cloning the high table on to the low since I wasn't planning on running anything less than 94.
God I miss that car.
 

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Well, after all that, I guess we should just run 89 octane and call it good lol! I will just try to avoid non "top tier" stations. And yes all gasoline comes from the same distribution pipes that supply the country, but each retailer decides what kind of additives to put in, as well as how often/well they maintain their tanks...I have seen a weird auxillary power type trailer plugged into the tanks (ventilation hose and electrical cables going into the ground where the tank fill points are) at the local Speedway numerous times, and their pumps are always in poor condition or broken! If they can maintain the pumps and the power supply units, what does the inside of those storage tanks look like??
 

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This topic never dies whether it is in a car or motorcycle, there are those that believe higher octane means more power. I won't repeat the facts already stated by others except that an engine will best served for life and economy by using the octane it was designed to use.

The easiest way to improve fuel mileage when choosing a fuel is to buy ethanol free gas. Ethanol has less energy content than gasoline, burning 100% gasoline will improve mileage over a 10% percent ethanol blend by about 3.3%. Most people won't see this difference because driving habits can wash these small percentages.

If you are averaging mid 30's per gallon it works out to about 12 to 15 extra miles per tank or an additional 1 mpg. Not much but a real gain.
 

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The manual also states that running premium will result in increase performance.

Most engines are tuned with high and low ignition tables. Which if is true for the Focus it would make sense why they recommend regular but also state that premium will increase performance(Page 354 "Octane recommendations" last sentence in the owners manual.). One day I'll hook it up to my Dash Hawk and try and figure it out.

My G8's had high and low octane tables and running on the low octane table the car made around 8HP less than the high octane table (Stock). It switched to the low octane table when it detected a predetermined knock count withing a set time frame. It was kind of a PITA when trying to tune the thing because it was pretty sensitive and switch over when it wasn't needed. I ended up just cloning the high table on to the low since I wasn't planning on running anything less than 94.
God I miss that car.
Finally someone who understands!
 

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The owners manual does state that using Premium Unleaded gas will increase performance. I just don't see the need to spend 10% more on premium fuel when the most I will get out of it is 2 - 3% more horsepower.
 

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Actually on pg 354 it talks about some parts of the country regular gas is 85 octane and that the car will run better on premium than 85.

It does not say it will run better with premium than the 87 octane available to most of us.

This is the third time in this thread i have mentioned this.
 

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Actually on pg 354 it talks about some parts of the country regular gas is 85 octane and that the car will run better on premium than 85.

It does not say it will run better with premium than the 87 octane available to most of us.

This is the third time in this thread i have mentioned this.
And you are correct, but many don't want to be bothered by facts. The fact is, if your car knocks moderately or heavily under load, including when starting from a stop, then it may be due to fuel with a low octane rating. In this case, change stations and run 87 octane, or switch to mid-grade or premium fuel with an indicated octane rating above 87.[read]
 

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Here in Australia the Focus uses the same 2 Liter GDI engine. However, all performance figures supplied by Ford here for the Focus, are explicitly stated as being in relation to Premium gas (the USA equivalent of 91 Octane).

In other words, the recommended fuel for the Focus is 91-98 RON (87-94 in USA) and I've read elsewhere that while it will run on regular, Premium is preferred.

The engine is rated in the USA at 120 kW (160 HP) and that's on regular. Here, the engine is rated at 125 kW (167 HP), but that's on Premium. No figures are available here for Regular.

It could be that the car is tuned differently here - I wouldn't know. However, the implication is that Premium gives an extra 7 HP.
 

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Actually on pg 354 it talks about some parts of the country regular gas is 85 octane and that the car will run better on premium than 85.

It does not say it will run better with premium than the 87 octane available to most of us.

This is the third time in this thread i have mentioned this.
Just because you've mentioned it 3 times doesn't mean you're correct.

Focus Owner's Guide Two Thousand & Twelve, Page 354, Para 4. (Canada)

"Your vehicle is designed to use "Regular" unleaded gasoline with a pump (R+M)/2 octane rating of 87. Some stations offer fuels posted as "Regular" with octane ratings below 87, particularly in high altitude areas. Fuels with octane levels below 87 are not recommended. Premium fuels will provide improved performance."

Now I'm not an English major but the last sentence doesn't have a dependent clause linking it to the previous sentences, nor does it have any conjoining words. This paragraph is providing us with 4 key pieces of information 1) You vehicle is designed to run on 87. 2) Some stations offer fuels with an octane rating below 87. 3) Running fuel with octane ratings below 87 is not recommended. 4) Running premium will improve performance. 1 and 4 are a bit conflicting but I think I covered my theory on that is my previous post. (Provided below)

Listen, I'm not saying your wrong, because I have no actual proof and the last sentence is a bit ambiguous however, from my interpretation of the manual it states that "Premium fuel will improve performance". It doesn't say ", therefor running premium fuel in areas where (R+M)/2 87 is not available will improve performance. I said right in my post "One day I'll figure it out" because at this time all I have is my interpretation of the manual.

My original post for your convenience.

The manual also states that running premium will result in increase performance.

Most modern engines are tuned with high and low ignition tables. Which if true for the Focus, it would make sense why they recommend regular but also state that premium will increase performance(Page 354 "Octane recommendations" last sentence in the owners manual.). One day I'll hook it up to my Dash Hawk and try and figure it out.

My G8's had high and low octane tables and running on the low octane table the car made around 8HP less than the high octane table (Stock). It switched to the low octane table when it detected a predetermined knock count withing a set time frame. It was kind of a PITA when trying to tune the thing because it was pretty sensitive and switch over when it wasn't needed. I ended up just cloning the high table on to the low since I wasn't planning on running anything less than 94.
God I miss that car.
EDIT
 

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The reason regular gas at high altitudes has a lower octane is because the thinner air lowers compression levels, and therefore makes detonation less likely with a lower octane fuel.
 

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Just because you've mentioned it 3 times doesn't mean you're correct.

Focus Owner's Guide Two Thousand & Twelve, Page 354, Para 4. (Canada)

"Your vehicle is designed to use "Regular" unleaded gasoline with a pump (R+M)/2 octane rating of 87. Some stations offer fuels posted as "Regular" with octane ratings below 87, particularly in high altitude areas. Fuels with octane levels below 87 are not recommended. Premium fuels will provide improved performance."

Now I'm not an English major but the last sentence doesn't have a dependent clause linking it to the previous sentences, nor does it have any conjoining words. This paragraph is providing us with 4 key pieces of information 1) You vehicle is designed to run on 87. 2) Some stations offer fuels with an octane rating below 87. 3) Running fuel with octane ratings below 87 is not recommended. 4) Running premium will improve performance. 1 and 4 are a bit conflicting but I think I covered my theory on that is my previous post. (Provided below)

Listen, I'm not saying your wrong, because I have no actual proof and the last sentence is a bit ambiguous however, from my interpretation of the manual it states that "Premium fuel will improve performance". It doesn't say ", therefor running premium fuel in areas where (R+M)/2 87 is not available will improve performance. I said right in my post "One day I'll figure it out" because at this time all I have is my interpretation of the manual.

My original post for your convenience.



EDIT
The last sentence is related to the others because it is part of the same paragraph, that is english grammar. If that sentence was not related it would be part of another paragraph.
 

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Why not just find the gas you like and use it? Who really cares if it is better or not? None of it is going to hurt your engine or void warranty.
 

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The manual is clear. Premium improves performance. Manual notwithstanding, it stands to reason that higher octane is beneficial for a car with 12 to 1 compression. There are two questions the manual and common automotive sense don't answer. First, does premium solve any of the complaints like shuddering? Some on this forum have reported that it does. I use premium and have had no shuddering or other issues. Second, is the added cost worth it? I doubt premium's added cost is worth the performance gains or MPG gain (if any -- regular may give better MPG).

So as I see it, premium is worth a try if you've had shuddering or other performance issues, or if you're a leadfoot who wants to see whether there is a power improvement.

Once I have about 4k miles, I intend to switch off premium to see how regular compares in the fuel economy department as that is my principal concern.
 
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