Decided to fill up with 89 octane fuel last weekend (it was only $.07 more per gallon) and I can definitely tell that the truck is running better. The owners manual says the Hemi likes like mid-grade, but will run on regular. Just my personal experience as I know that some run regular gas and can't tell the difference. I thnk it is mid-grade from now on.

 

Well for me regular is either 87 or 89. And plus is either 89 or 91 . And premium is either 93 or 94octane. I usaully fill on 89 or 91 octane.

 

i ran regular in my 03 Hemi for 3 months and only got 10.3 mpg since i do very local driving....mostly not over 5 miles on way. It started stalling and running poorly then finally the check engine light came on so i took it to the dealer. All 8 plugs were shot and the ECU had set itself so that it was only making 300hp instead of the full 345, after having it serviced, cleaned, remapped, and tuned-up back to stock, i refused to pay the bill until they drained my gas tank and filled it up with 89...on their tab. They did this, and they were happy to which made my jaw hit the floor. Now, it runs like a champ and i even find myself starting the motor and standing by the exhaust pipe just to hear it rumble....I LOVE THIS TRUCK. If it could cook, i would stay single forever, hahahaha!

 

Yeah whatever, I have a truck and I'm gonna treat it like a truck. Gas is gas, 06' 1500 QC Hemi 4x4 is what I have. 87 is just fine with me, you really don't need anything higher, and if you feel anything it's your head reminding you about 89.

 

Dude, are you illiterate? in your manual it tells u, ask anyone who has tried regular, and switched to mid-grade. It's a prefered fuel and WILL run better. Dont get cocky, i had to pay $400 to fix all the **** that went wrong after i ran regular in the damn thing. You'll pay for it later, watch, i bet it will even show by ur first major service.

 

Tight Wads! If you are going to drive a HEMI give her what she needs! I have run 91-93 octane from the day bought my Hemi! Come on $.20 a gallon more and a 20 gal tank is only $4.00 extra.

 

It's a brand new truck! If anything, the damn dealership is gonna fix it. My owner manual says to use 87, that's what I'm doing, it's not like I'm going to be driving this truck forever. I bet you guys use synthetic oil also, OMG.

 

Modern Engine 101....Here is how it works on new vehicals with modern engine managment computers. If the computer senses knocking like some, but not all 87oct gas can do in the HEMI motor, it will retard the timing which will output less horsepower. Its that simple. This is what most chip upgrades do and require 91oct and above for the added hp they give. The OEM computer is mapped for 89oct or better grade 87oct. Humidity, elevation, and temp all play a role on if 87oct will cause knocking or detonation. 87oct may work for some climates in one area but not all. 89oct is the default oct rating. Will high oct gas like 94oct increase even more power than mid-grade gas? No, the engine managment will only advance its timing for 89oct. Any oct above 89 will not prduce more hp unless a aftermarket chip is in play. The days of wrenching hp gains have switched to computer mapping upgrades for that little edge in hp.

 

If you have an 06' the owners manual says the preffered grade is 89 but you are allowed to use 87.

 

I shared my story about my Hemi and running it on 87, read Mystro's post and it proves that what happened to me is a direct effect of using 87 in a hot climate and mostly humid conditions.