I was curious to see if anyone has tested to see whether running 87 octane in a stock R/T has a negative effect on MPG or even performance compared to 93 Octane.

 

Personally, I've never ran 87 in my Daytona Charger. I run only at least 91 because it is chipped (Jet 2) and is recommended by the chip manufacturer. However, according to many experts, you needlessly spend extra money by using higher octane gasoline in a car designed by the factory to use a lower grade. And, they say it doesn't help your car at all by giving it a "treat".I believe you don't get a boost by putting in a higher octane fuel in a car that doesn't need it --


MN

 

Before I "modded" my R/T, I used 87 in it. Now, since I have the Flashpaq tuner, I've been running it tuned to 91 and get, on the highway, between 26 and 29 mpg. With the cost of gas now, I'm going to "detune" it down to 87 and see how she does.

dave

 

Sounds good to me thanks

 

I have run 87 no negative effect. I did have some pinging.


I have Super chips power programmer set to 91 and the car screams. Add about 10-15 hp

 

well without sounding to technical octane refers to the pressure level needed to ignite the gas the higher the octane the more pressure that can be exerted on the gas before detonation occurs.usually thats controlled by advancing the timing or leaving it stock.the cars timing is preset at the factory to detonate for 87 octane .using higher octane will cause pinging because its detonating on the way down causing the pinging.so yes its useless unless the cars timing is advanced.

 

I have been wondering the same thing so this week I decided to find out for myself if octane rating had any effect on mpg. I picked up my R/T on Saturday and had it's first trip this week. When I picked the Charger up at the dealer with 3/4 tank of gas and 121 miles on the clock. I managed to run out the tank on Sunday and Monday getting to know my new car. On Tuesday, I filled the tank with 93 octane gas at $3.43 per gallon and started my run for the week. I got 23.6mpg. I re-filled the tank with 87 octane at $ 3.02 per gallon and got 24.2 mpg. My third tank was 91 octane at $3.11 per gallon. I got 23.8 mpg. I pulled in the garage tonight with 1507 miles on the clock. My driving was done on I-24, I-75, I-20 and I-95 in Tennessee, Georgia, South Carolina and North Carolina with very few miles done off the interstate. Most was with the cruise control set between 75 and 80. I didn't get any pinging with any of the fuel.

 

put you got the best mileage with the 87 and at a difference of 40 cents a gallonover 19 gallons that alomst 10 dollars or about 3 1/2 gallons.that also should factor in as well.

 

USed both no problems.Been doin the 87 for some time now had no ping with either .

 

Chrisdridley,

You proved a point = that a stock engined car doesn't get better MPG with more expensive fuel. Very interesting post you did. Good job!


MN