I took a trip from omaha to chicago, 500 miles 1 way. Had some oil laying around and did a fresh dino oil change got 30.89 mpg. When I left from chicago, did a mobile 1 full syn change, and got 30.75mpg. The Magnum started with 5200 miles on it. Both trips I used BP 89 gas, lock the cruise at 72mph(2200 rpm). So from my observation, Im not wasting the extra $20 for syn. As said in previous threads with changing oil @ 3000 miles, I dont see any advantage to syn. So let the oil discussion begin ahhahaa.

 

Down hill both ways?? lol

 

I had just the opposite happen. I don't recall the exact numbers, but the Mobil 1 gave me 1 MPG more than whatever was in truck.

Too. I switched from Castrol GTX to Castrol Full Synthetic in my Coronet. The engine would turn over noticably faster than with the dino oil.

It's been said alot here and other forums, if you're not going to increase the change intervals of the oil with the synthetic, you're wasting your money.

 

Most people running synthetic are NOT doing so for mileage gains. In fact I have never that argument in favor of running synthetic. The reason to run sythetic is for the HUGE improvements it offers against breakdown of additive packages especially at high RPM's over lond periods of time.

 

wow, good numbers.
any elevation changes?
i took my mag from LA ot Mammoth mountain...about a 360 mile trip.
averaged 18mpg goin there and about 24mpg coming back.
wind could also be a factor i.e. trade winds.
still 30 mpg!?! is it my driving style?????
i wish i can post some mpg numbers like that...
but i never use cruise and on long open stretches, let just say i dont have any discipline.

btw, if anyone is from the area, its a very slight incline...
very unnoticeable until the last 30 miles or so...the 18 mpg was marked at the city of bishop (just before the big incline)

 

I have made three trips to Vegas from Kern County, CA.....my mileage
was in the low 20's for each of the trips...may have a mpg or so.

I switched to synthetic for reasons other than mileage as well....
My little truck has been run hard and I am pushing 270,000 miles,
run on synthetic...

 

From the mileage figures you got, you must have the V6 motor, right?

Best I get from my RT is 26 MPG on highway, that is doing 75-77 MPH.

Bob

 

From the mileage figures you got, you must have the V6 motor, right? Yes it is an SXT, the main reason I traded in the '02 Ram on this was the milage inprovement. Sure beats the 15 highway i was getting in the Ram.

Downhill both ways? Nope but Iowa is flat and boring as hell.

Most people running synthetic are NOT doing so for mileage gains. In fact I have never that argument in favor of running synthetic.

From
Mobile 1 Website
Benefits:
Outstanding wear protection.
Excellent high- and low-temperature performance.
Pours at temperatures as low as -53ºF and protects at oil temperatures as high as 400ºF.
Improved protection against sludge and harmful deposits.
Excellent fuel economy benefits (specific grades/viscosities).

 

I thought you could not switch between sythentic and regular oil?

I thought once you swtiched you could not go back to regular?

 

You can go back and forth although I can't imagine why you would want to.