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OK, before anyone starts a thread to string me up for committing a Chrysler sacrilege keep in mind that I lost my job last month in the housing industry and so the alternative to my question here might be my pushing my 300 around town instead of driving it.

OK, that being said, has anyone ever tried regular gas in a 5.7? If so, how was it?

At more than $60 a tank for the mid-range it calls for, it's beginning to hurt!
 

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The manual for the 07C's state that you can use 87 or 89 octane with optimum performance coming from the 89 octane. So I switched from 89 to 87 for 3 tankfuls just to see the difference and it seems to feel a tad less power when you want to pass. I switched back to 89 and noticed the difference right away. Will stay with the 89 octane as I like it better.
 

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At more than $60 a tank for the mid-range it calls for, it's beginning to hurt!
Tough situation you're in. I hope you get it sorted out fast.

Just make sure you realize what you're saving - or not - by going with the 87. Take your average fill-up gallons X the price differential and see if it's worth it to you. If you fit the average, you'll save about $2.00 a week. It'll run fine on 87, just not as fine as on 89. The PCM will retard timing to compensate for the lower octane and eliminate ping, but it will lose some power too.

If running 87 would drop that $60 fill-up to $40 I'd be all over it. So would a lot of others. For $2, I'll find some other way to cut back. Best of luck finding the job you were meant to have!
 

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If running 87 would drop that $60 fill-up to $40 I'd be all over it. So would a lot of others. For $2, I'll find some other way to cut back. Best of luck finding the job you were meant to have!
Amen! The price difference where I live is about .10 a gallon between regular and midgrade. If you drive 15,000 miles a year, and average 15 mpg (lets say it's all city driving) you use 1000 gallons of gasoline per year, or 19.23 gallons per week. So you would save $1.92 a week.

The car will run on 87, and you won't damage it. But what's the point? 89 octane is what the car was designed to use for optimum performance and economy.
 

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I have been involved in several threads about 87 octane vs. 89 octane for the 5.7. The manual clearly states that 87 or 89 is acceptable..89 being preferred. I have found through experience for my 5.7L that 87 octane appears to run fine. The engine runs smooth, my gas mileage is higher than average 18-20 around town and 28 plus on trips, and my fuel costs are at least 10 cents less per gallon verses 89. One possible answer is that much of the 87 gas sold really is several points higher in octane than advertised. I also think that ethanol is used by many oil distributors to increase octane rating kills several miles per gallon off fuel mileage. With all of this in mind running 87 has a two fold advantage: 1) cheaper fuel price 2) higher miles per gallon due to more mpg because of no ethanol... One could conclude that 87 is a better fuel because it takes less of it to push the car a mile down the road. On the other hand if you drive the car constantly harder the ECM will want to advance the timing more and 89 octane may make sense for that type of driving. I really think this dog is just as happy with hamburger as with steak unless you really get on it a lot.....
 
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