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Okay, here's the rundown...

01 4-DR ZTS
Bosch Platinum Plugs
Bosch Twin-Core Wireset
Short Style CAI. ACTUALLY, I just ripped the air box out an put a "GREEN-FLOW" cone filter off the end of the MAF

Alright, come on [:(] stop laughing at me!!

When your broke you will take all the HP you can get. I know it's not AEM or anything fancy but It gets me off the line a little faster.

Anyway, since the engine is mostly stock what's the deal with gasoline???

I am in the US, I only mention this cause I know gas is different other places.

I have the following options ( 87 - - 89 -- 93 -- 94) , I know the book says 87 but what's the real story here. Ford couldn't even give me a straight answer. Is there any gain from using a higher octane or is it better to use the 87.

And will there be any long-term effects of using one over the other??

If anyone can give some advice to the broke Foci owner over here, please do..


([paranoid]and stop laughing at my intake!![?|] )
 

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87. higher octanes are for engines with more compression... lower octanes actually burn easier. a higher octane wont burn as completely in our engines. although they do say if the engine developes a knock, a couple of tanks of 93 will help that....

from what i've read, you shouldn't use lower in octane in larger engines (like on of those huge ass 5.8l trans am v8's, for instance) because the compression of the cylinder can ignite the gas befoer the spark plugs go off.... thas why the higher octane gases are for larger engines...



At least thats how i understood what i read, if i'm wrong correct me....
 

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octane doesn't make hp... octane allows you to do things to the engine that make hp and not detonate or ping. Like raise compresion. All the grades of gasoline have the same additives too, so your engine isn't getting "cleaner" by using higher octane. Biggest rule for best performance is to use a gas brand that doesn't have methanol in it.
 

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Stay away from those cheap gas stations with 'gasahol.' [nono] [thumbd]
Some of those other cheap gas stations have some sort of gasahol. I guess that's why their gas is so cheap. Just look for the sticker on the gas pump that states that the gas contains 10% of something other than gas. I think if you want to use higher octane gas with a .5% increase in performance, get a diablosport or superchip. Otherwise, just use the 87.
[:)]
 

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Octane=resistance to detonation. High compression & heavily advanced timing are both examples of circumstances that require higher octane though there are other things that can influence this as well. Too low of octane for a particular engine results in pre-ignition a.k.a detonation. As the piston travels up on it's compression stroke the fuel/air mixture ignites due to the heat in the combustion chamber not because of the spark from the spark plug as it should. Basically it blows up too early and this is very bad for the engine. Modern cars only see gains from higher octane if they require it by design or if they are very heavily modded. For a car that is designed to run high octane, when low octane gas is introduced the computer senses this and retards the timing and/or boost ( if applicable) to prevent detonation which is felt by the driver as less power, basically it detunes the engine to prevent harm. If your car doesn't need higher octane nothing will change except you are paying more for gas that doesn't make your car run any better. Of course the only way to know for sure is to try a tank and see. If you are a racer it would be nice to make runs with both types of gas so you don't just "think" it runs better. Also keeping track of you MPG can give you some info as to which gas is better for you. It doesn't matter what motor you have, what size, how it is modded or anything else If you don't need higher octane you are trully wasting your money.
 

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Yes. Well said. I'm actually surprised that the Focus only requires 87 octane. Coming from V8's, 9.6:1 compression is considered medium-medium high in my book and I would probably run 91 octane if I didn't know any better. I've had v8 cars that pinged at 9:1 compression with 91 octane with moddest timing of 10 degrees initial. Now, custom programming took care of that problem which tells me the car was setup to run a bit lean from the factory (Meaning 9:1 compression, 10 degrees inital timing, and 91 octane should not naturally ping or detonate).
 

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Broken cars s[:)][:)][:)] :(
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ummm yah...I guess I'll drop to using the lower end gas for my car...I always use the mid grade....now I'll go for the lower and save myself 10 cents a gallon....oh is B.P. Amoco gas any good?!?!? thats the only place I EVER go to get gas unless its an emergency
-Joe
 

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My2KFocus said:
Stay away from those cheap gas stations with 'gasahol.' [nono] [thumbd]
Some of those other cheap gas stations have some sort of gasahol. I guess that's why their gas is so cheap. Just look for the sticker on the gas pump that states that the gas contains 10% of something other than gas.[:)]
I was driving through New York State and Connecticut last week. Sunoco and Mobil pumps generally had a sticker saying something like the gasoline could contain up to 10% ethanol.
 

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a too rich tuning will cause detonation sooner than a lean burning engine. also, there are some cars that will actually advance the timing if it detects a higher octane gasoline, but unfortuneately, our focuses aren't one of those. until you start seriously modifying your engine, all you need is 87. of course, hotter air will increase your chances of detonation, so if you live in a warmer climate, you might think about 89 during the summer. and definitely stay away from gasahol. I'd rather pay out the a** for race gas than run gasahol in my car
 

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so in a word, using higher octane gas on our engines won't do crap. we don't really have high enough compression to have to worry about detonation.

there is a certain amount of additives that oil companies can add to their gas, alcohol is cheaper than petrol so the more they add the cheaper it is, it is also bad for your engine, hence if you go to a place like arco you will experience backfires and your engine might occassionally ping, i go to unical (76) or shell. i used to go to texaco before shell bought it : (
 

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running a higher octane isn't going to hurt anything. You won't gain anything unless you are running an aggressive setup. Some race cars gain HP from their octane fuel. But its HIGH octance, way past 100. So us being stock motors 87 or 93, its not going to matter, you won't gain anything. The 93 will burn slower and cleaner. 87 burns fast. 87 burns easier. Ford recommends 87 because thats the tune, the car is tuned to run on the low costing gas to help with fuel economy and such. I usually run higher octane fuel just because i want too. I run 89 or 93 depending on prices. They burn cleaner and if your car is straight piped, 93 smells awesome![thumb]
 

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tension001 said:
I usually run higher octane fuel just because i want too. I run 89 or 93 depending on prices. They burn cleaner and if your car is straight piped, 93 smells awesome![thumb]
What do you mean 89 or 93 burn "cleaner" ?
 

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89 and 93 octane do not burn cleaner. That is a falacy. All higher octanes do is resist knock. In fact, due to the slower burning nature of higher octane fuels, you may be running "dirtier" by spewing an infintesimally smaller amount of HCs out the tailpipe. Look, just run the 87 octane and you can't go wrong with an engine with stock CR. Anything more is a waste of money, anything less will endanger the engine.
 
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