I tend to agree with this. Higher octane is necessary for higher compression, period. I run premium in my Civic because it's running 10.5:1 compression. I run regular in my XJ because it runs 8.8:1.

All more octane does is resist predetonation from advanced timing, high compression, or boost.

If you're seeing higher mpg from premium on an 8.8:1 XJ, I agree with the notion that it's because regular gas these days tends to be 10% ethanol, while premium is 100% gasoline. Ethanol contains less stored energy than gasoline, and generally the higher the ethanol percentage, the lower the gas mileage.

 

The ethanol statement is only true for about 3 states. Tell ya right now NJ is not one of them, if anyone wants ethanol free fuel you have to buy av gas.

 

Does your owners manual say premium fuel?

http://automobiles.honda.com/civic-s...fications.aspx

 

I usually use premium when my Jeep's are due for California smog tests, the reason being as the fuel burns hotter the emissions are less from the exhaust pipe.

 

Huh, I thought it was the other way around, premium burned a little slower/cooler than regular.

 

My car's original manual says regular fuel, but the owner's manual for the car that my engine came from does say premium only... 2001 Acura Integra GSR engine in a 2000 Civic. The GSR officially requires premium.

 

I was wondering if it was a stock Civic motor.

 

Here in Iowa, the home of ethanol, we have 3 grades of fuel. Cheapest to highest they are Ethanol 89 octane, regular or super unleaded (no alcohol) 87 octane and premium...don't know the octane.

Even though ethanol has higher octane it is widely accepted that 100% gasoline will give better mileage.

 

What are the three states?

 

Not exactly sure, may be few more/less. I know one is florida, but only at sunoco's. And wyoming as well.

 

Anybody found any links saying premium is better than regular when the engine is designed for regular?

 

Its not lol

You debunked the myth for many

 

Yes directly into TB But like was stated earlyer must be VERY careful, when injecting it this way allowes proper distrubtion throughout intake ports. tube diameter that of WD-40 red straw im using hobby hose from nitro rc truck. Do your own reasearch for what is right for you good luck

 

I buy premium here in cove OR. because it has no Ethanol. It cost me about 8% more than the regular with Ethanol but in my F150 I get between 17% and 23% better mileage. I use it in everything I own Motorcycle, Cherokee, 1948 CJ2A, and a supercharged Buick, but it is suppose to run 93 octane. I don't keep track of mileage for the Motorcycle because it only has a 5.9 gallon tank and I ride it hard, the Cherokee and the CJ2A I drive mostly in the mountains so I don't keep track of their mileage either.

 

"debunked" - that's an awesome word, needs to be used more often.