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bosca418 01-22-2011 10:42 PM

Gasoline
 
Does anyone use premium? Is it not necessary?

mr_bots 01-22-2011 10:45 PM

Re: Gasoline
 
Not necessary. Mid-grade is recommended on the Hemi; Regular is recommended for the V6.

rich mac 01-22-2011 10:47 PM

Re: Gasoline
 
The manual says to use 87 octane in the V6 and 89 octane in the V8. Most will agree that using a higher octane than recommended is not necessary. In the past, some gasolines had higher additive levels in the preimum grades, but I don't think that is the case anymore.

bosca418 01-22-2011 10:52 PM

Re: Gasoline
 
How many total miles are you expected to get out of a full tank on a hemi?

Breitling65 01-23-2011 06:55 AM

Re: Gasoline
 
Quote:

Originally Posted by bosca418 (Post 339911)
Does anyone use premium? Is it not necessary?


I am thinking of trying 89 on my V6 and see difference in miles. So far I am getting 23 mpg on highway with speed between 50 and 75mph. For city it is around 17mph. I am interesting to see power difference as well.

Navy1 01-23-2011 07:20 AM

Re: Gasoline
 
I use 89 Octane in my Hemi. The total miles you achieve on a tank depends a lot on your driving habits, type of driving (highway/city/mixed) and weather its winter blended fuel or summer...you'll get a little less with winter blended fuel. Overall, I'm getting about 310 miles a tank full on mixed driving with winter blended fuel and I go up and down some mountains too. On a recent trip that was mostly highway, I got 385 miles on 20 gallons before I fueled up...18.5 miles per gallon.

WK2OverlandII 01-23-2011 10:50 AM

Re: Gasoline
 
Quote:

Originally Posted by bosca418 (Post 339911)
Does anyone use premium? Is it not necessary?

Please reference another thread...post number 30.

http://www.jeepgarage.org/f73/v8-highway-gas-mileage-17733-2.html

JTS97Z28 01-23-2011 11:07 AM

Re: Gasoline
 
Use what the manual recommends...89 octane. Using premium fuel in a car not designed to burn premium fuel is not only a waste of money, but the engine will possibly not be running optimally either.

Breitling65 01-23-2011 11:39 AM

Re: Gasoline
 
Quote:

Originally Posted by JTS97Z28 (Post 340137)
Use what the manual recommends...89 octane. Using premium fuel in a car not designed to burn premium fuel is not only a waste of money, but the engine will possibly not be running optimally either.


You probably don't know what is octane number is right? It is number that corresponds to the gasoline resistance against of detonation; detonation is very harmful thing to the engine. Fuel explodes instead of burning; forces are 1000 times stronger while damaging parts.
So, higher octane number is better resistance against detonation, better burning and as result better engine overall performance. Higher octane can't harm anything, it is better for any gasoline engine.


JTS97Z28 01-23-2011 12:45 PM

Re: Gasoline
 
Quote:

Originally Posted by Breitling65 (Post 340155)
So, higher octane number is better resistance against detonation, better burning and as result better engine overall performance. Higher octane can't harm anything, it is better for any gasoline engine.


Ok I will say the same thing again. On a engine NOT designed to run on premium, by filling it with premium you are not improving performance, you are not improving fuel economy, and you are not improving the longevity of your motor. If you have a high compression motor those are usually designed to run on premium and ONLY those motors will truely benefit from the higher octane rating. Maybe some grades of premium have a slightly higher concentrate of detergents, but in modern engines I dont think you would ever see any benefits just from the added detergents.
You can burn premium in a regular burning car all you want, will it hurt the motor? No, all im saying is that there are absolutely no benefits to it on a motor that doesnt require it. When you have a high compression motor that requires premium and you run regular, THATS when you can really get the detonation issues and like you said can potentially damage your motor. My owners manual says mid grade 89 recommended...thats what I will use.

Breitling65 01-23-2011 12:55 PM

Re: Gasoline
 
Quote:

Originally Posted by JTS97Z28 (Post 340137)
Use what the manual recommends...89 octane. Using premium fuel in a car not designed to burn premium fuel is not only a waste of money, but the engine will possibly not be running optimally either.

Quote:

Originally Posted by JTS97Z28 (Post 340196)
Ok I will say the same thing again. On a engine NOT designed to run on premium, by filling it with premium you are not improving performance, you are not improving fuel economy, and you are not improving the longevity of your motor. If you have a high compression motor those are usually designed to run on premium and ONLY those motors will truely benefit from the higher octane rating. Maybe some grades of premium have a slightly higher concentrate of detergents, but in modern engines I dont think you would ever see any benefits just from the added detergents.
You can burn premium in a regular burning car all you want, will it hurt the motor? No, all im saying is that there are absolutely no benefits to it on a motor that doesnt require it. When you have a high compression motor that requires premium and you run regular, THATS when you can really get the detonation issues and like you said can potentially damage your motor. My owners manual says mid grade 89 recommended...thats what I will use.


I am not saying you should use high octane, I am saying that you don't know what is octane number and detonation means saying that it could harm. It is not and has nothing to do with compression. Benefits of higher grade octane is better temperature balance, better engine performance, better mileage, etc. It is theory and no one could change, it is like sun and moon or Earth is round :)
It is good that you are reading book and follow what manufacturer said but in many cases they are writing this to the book to increase sale of particular car in US since lots of people would not pick this car if you write "required 93" :)

NetJunkie 01-23-2011 02:46 PM

Re: Gasoline
 
Better mileage? Says who. I get better on 87 than I do on 89 in my 5.7 GC. Doesn't have anything to do with compression? Yeah, it does. Higher compression means lower octane gas will ignite sooner which is why you get detonation if your octane is too low on a high compression engine. A lower compression engine doesn't care. If you aren't getting detonation running 87 under heavy load when the engine is hot then there is no need to go 89 or higher. Same reason I used to run 104 octane in my Z06 Vette when we'd do dyno days in July. Running 93 I'd see the PCM pull timing at high RPMs because of detonation due to heat (and high compression).

Waste the money if you want to and if it makes you feel better, do it. But to say either the V6 or V8 will run "better" on 93 is not correct unless, again, the computer is pulling timing due to detonation.

No one is saying there will be damage or a significant downside to using 93 or higher...but in almost all cases you won't get a benefit either.


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