My challenger is a 2013 5.7 manual.... so I have to have 91 or higher, but the salesman. ... and dealership for that matter didn't realize it and was putting 87 in it. The manual says regular is fine for the 5.7 auto. Wonder why they are different.
Great question I an going to take delivery on my 2013 R/T soon. I want to know what is best for it. It is a automatic auto stick with paddle shifters.
The manual for the 2010 says to use 89 for the 5.7L. I run 93 in mine. The dealership says that there is no advantage to using a higher grade fuel. Mine is a weekend driver so I use the higher octane.
My salesman who picked it up and brought it home 250 miles ran 89 mid grade and it runs great on that so that's what I will use. the book says 87 regular is fine but I want to go UP a grade to 89 as that's what is in the tank now and I have 1/4 th tank left & my dash display says I have 115 miles left on that 1/4 th tank. Bert
For auto RT's the manual states that you can use 87 but 89 is recommended. For manual RT's 91+ is required. I dont know about SRT's. If you put lower grade in it will not hurt the engine, like others have stated it will just retard timing and decrease performance. I have played around checking out different gas stations and grades and logging my findings with the trinity. 93 When in drive, without manual shift or sport mode, I would get up to 5.5 ST and 1 LT Knock Retard. Using Chevron gas and manual shift mode the highest I have seen is 1 ST. 91 When in drive, without manual shift or sport mode, I would get up to 5.5 ST and 2 LT Knock Retard. In manual shift mode it would get up to 4 ST with 0 LT.
My manual says in the fluids section that 5.7 needs 91 octane. it doesn't mention automatic or manual. I have to reread the thing because I no I saw it was ok to run 89, now I can't find that part. I haven't looked at the DVD that came with the owners manual but I think it may have more information.
Thats the user guide not the manual. If you check the actual owners manual it will tell you the difference between auto and stick.
The manual trans cars are slightly higher compression than the auto cars. Some sites list dual specs for the 2010 R/T's as 370hp/398tq for the auto and 375hp/404tq for the manual cars. Could be due to the slight difference in compression rations and/or tuning.