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Discussion Starter · #1 ·
It's cheaper to us 93 over 87, if there's a .20 cent difference and your getting 3 mpg more. Compare: 87 cost say $2.00 divided by 17 mpg = .1176 cents a mike. 93 cost $2.20 divided by 20 mpg = .11 cents

There are the results that I see from using 93 over 87.
And my truck runs better.
 

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Interesting...Is there any truth to the theory that 93 octane causes more carbon build in the engine, and could actually be more harmful?
 

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I've never seen a 3 mpg increase due solely to different octane on my truck, and I am extremely anal about keeping track. If that's what you get.....more power to ya!
 

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I've seen a slight difference, but that would be like 1-1.5 MPG. Not enough to matter in my book.
 

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ShowStop said:
I've seen a slight difference, but that would be like 1-1.5 MPG. Not enough to matter in my book.
He has an 05. ITs a higher compression engine (10.0-1), the older 3.4 (NON SC) will not benifit from 93 octane (compression ratio is 9.6-1). Those of you who think it does, its all in your head. The higher octane can actually make your car run rougher.

Later,

Chris
 

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Discussion Starter · #7 ·
Well my 99 3.4L has 90K+ miles and for the past 20k mile my truck pings on lower octane. I guess I didn't go into detail on my results. If I run 3 tanks of 87. Then 93 for the next 3 tanks. I see atless 2-3 mpg better. Plus my motor run smoother and don't ping.
 

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the higher octane the better, 90,000+ miles on high octane still runs like brand new....
 

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wvtaco said:
Interesting...Is there any truth to the theory that 93 octane causes more carbon build in the engine, and could actually be more harmful?
Interesting...They use more detergents in premium and the fuel is more refined so it would burn cleaner and leave Less carbon behind!
 

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Shakerhood said:
Interesting...They use more detergents in premium and the fuel is more refined so it would burn cleaner and leave Less carbon behind!
Sounds good, thanks.
 

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I have been running 85 octane in my truck lately and my rough math says my mpg is under 17 mpg compared to using the 87 octane (mid grade in CO) at getting over 17 mpg. Hmmm...
 

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DriftinCO said:
I have been running 85 octane in my truck lately and my rough math says my mpg is under 17 mpg compared to using the 87 octane (mid grade in CO) at getting over 17 mpg. Hmmm...
Now here is the only example where a higher octane will benefit a stock engine. Your truck is tuned for 87 octane - look in the owner's manual. Running 85 will cause the computer to retard the timing and lower performance and gas mileage. Switch to 87 octane, it is the best for your engine.

Running higher octane (for example running 93 in a stock 3.4L V6) is a waste of money. If a stock engine designed for 87 pings on 87 then it has deposits that have raised the compression ratio (probably caused by incomplete burn of slower burning 93 octane!!) Anyone with this condition should run some seafoam through and then switch back to 87.

I can't believe the number of people who pay extra for more octane than their engine requires. The most common method of raising octane is adding methanol which has a lower BTU content than gasoline. So they are paying more money for less BTUs. Makes no sense.
 

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flatlandtacoma said:
Now here is the only example where a higher octane will benefit a stock engine. Your truck is tuned for 87 octane - look in the owner's manual. Running 85 will cause the computer to retard the timing and lower performance and gas mileage. Switch to 87 octane, it is the best for your engine.

Running higher octane (for example running 93 in a stock 3.4L V6) is a waste of money. If a stock engine designed for 87 pings on 87 then it has deposits that have raised the compression ratio (probably caused by incomplete burn of slower burning 93 octane!!) Anyone with this condition should run some seafoam through and then switch back to 87.

I can't believe the number of people who pay extra for more octane than their engine requires. The most common method of raising octane is adding methanol which has a lower BTU content than gasoline. So they are paying more money for less BTUs. Makes no sense.

He lives in CO, were the air is thinner. All the mountian states have lower octane gas.
 

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Shakerhood said:
Interesting...They use more detergents in premium and the fuel is more refined so it would burn cleaner and leave Less carbon behind!
I don't think you don't understand what causes carbon build up nor do you understand what the detergents in gasoline do.

The carbon build up is left behind by fuel that didn't completely burn.

Detergents are designed to help break up carbon build up. Detergents do not help the fuel burn cleaner.

Premium gas does not container higher amounts of detergent. It contains more octane.
 

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ShawnTRD said:
Well my 99 3.4L has 90K+ miles and for the past 20k mile my truck pings on lower octane. I guess I didn't go into detail on my results. If I run 3 tanks of 87. Then 93 for the next 3 tanks. I see atless 2-3 mpg better. Plus my motor run smoother and don't ping.
If this is true your motor is very dirty and/or broken.
 

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I've just always run it because it was required in my previous vehicle and I'm used to paying extra...if it doesn't help my motor I can't see where it's hurting it; or is it?
Ryan
 

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BigBadBob0 said:
I don't think you don't understand what causes carbon build up nor do you understand what the detergents in gasoline do.

The carbon build up is left behind by fuel that didn't completely burn.

Detergents are designed to help break up carbon build up. Detergents do not help the fuel burn cleaner.

Premium gas does not container higher amounts of detergent. It contains more octane.
I understand fully how fuel is burned. First off Premium is more refined than regular regardless of detergents, which makes it cleaner burning from the start. When the Automakers go to try to register a vehicle with the EPA the truck Chevron Premium in from out of state, so if just plain old 87 from the 7 - 11 is going to burn cleaner, why would they spend the extra on Premium?
 

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Shakerhood said:
I understand fully how fuel is burned. First off Premium is more refined than regular regardless of detergents, which makes it cleaner burning from the start.
More refined? Not hardly. Higher octane, yes. You can add water to gasoline and give it a higher octane rating. The most common method is adding methanol which has a higher BTU content than water but much less than gasoline.

Shakerhood said:
When the Automakers go to try to register a vehicle with the EPA the truck Chevron Premium in from out of state, so if just plain old 87 from the 7 - 11 is going to burn cleaner, why would they spend the extra on Premium?
I'm not sure what you are talking about, but if you are talking about the EPA fuel economy tests, I can assure you they are required to use the same 87 octane fuel that is recommended in the owner's manual.

Unless you have a method of raising the compression ratio (forced induction or aftermarket pistons, heads) or advancing the timing, there is no advantage to buying higher octane fuel than recommended for a stock computer controlled engine in proper tune. The only thing higher octane fuel will cause is incomplete combustion.
 

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flatlandtacoma said:
Unless you have a method of raising the compression ratio (forced induction or aftermarket pistons, heads) or advancing the timing, there is no advantage to buying higher octane fuel than recommended for a stock computer controlled engine in proper tune. The only thing higher octane fuel will cause is incomplete combustion.
Actually, the ECU will dial in more timing advance when you run higher octane fuel. Yes, I have the equipment to see this. Is it worth paying for premium gas? Not really.
 
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