Apparently my 2008 dodge 4x4 Hemi is supposed to be running on the 91 Octane, but I have been using the cheap stuff. I started to notice when I start it up in the morning it doesn't run real well and acts like it is missing a little. Is anyone else using the cheap gas in the 08/09 Dodges and if so are you experiencing any issues? If I purchased and installed a Tune (don't know much about this) of some sort can I then run the cheaper gas? I am sure that's why I only get 11. something miles per gallon no matter if I have my foot in it highway or in town doesn't seem to matter don't get any better than maybe breaking 12 on occasion.

 

im pretty sure the hemi is recommended for 89 octane. i put 87 for a little bit didnt notice anything but i went back up to 89 and it runs great.

 

What tuner are you using and which tune do you have loaded? Most tunes require 91 or 93 octane, because of the timing advance, but a stock hemi only needs 89. There are a few running on 87 with no problems, and there are some who have run 87 and had problems. The way I see it, a couple extra bucks a tank is cheaper than a major repair.

 

i don't know about the 08 and 09's,they are probably no different, but I know for my 05 it is recommended from the factory to run 89. I run 93 ocassionally but mostly 89. My Hemi runs great on the 89 and for the few dollars more per tankful its worth it.

 

Yes, most tuners have an "economy" tune built in. It basically retards timing enough so that pre-detonation is not a problem. Plus does offer some performance benefits over stock...

 

"... 91 preferred, 89 acceptable, 93 not recommended..."

 

why not 93? Just won't benefit anything is all.

I run a 91oct tune with my DSP(DiabloSport) and use 93oct. gas. My read-out has been pegged at 11mpg for a few months now, but i do alot of towing/city driving.
I would run 89 or 91oct in a stock Hemi and nothing but 91 and 93oct if you install a tune! 87 is junk for these engines and will cause you problems for the future.

 

Well apparently I was confused I just looked in up in the owners manual. 5.7L Engine: 87 - Acceptable but 89 - Recommended. Not sure where I saw the 91 Octane comment. I have been running the 87 which is probably my problem - going to switch to the 89.

Oh and I don't currently have a tune just inquiring on if that allows you to run on lower Octane or what exactly is the purpose of the Tune.

 

I wonder if I'd notice a difference, my 2008 is designed to run on e85 but I've never run anything but 87, do you think there would be a noticeable difference bumping up to 89 or 91 given that I'm running a stock setup? I have had no pre-detonation issues (that I could hear)

 

The manual said that if the gas tank lid was labled E85 then you are good to run that but otherwise don't run that or the 10% methanol because it'll cause fuel system damage. I just think that using the cheap kwik shop gas is causing some problems. I am just going to buck up and strickly run 89 and see if my ride idles better and improves on the gas mileage. Spent too much money to jack my ride up by putting bad gas in there!