what the highes of gas octane can a hemi handle its 2008 and i believe the gas is 105 octane the one that i can get would it be safe to put it in my truck

 

Waste of money. Follow the manual -- minimum 89, maximum 91. Unless you have a tune, more octane has no benefit.

 

the dealership put 92/93 octane in my 05 and my wifes 06 1500s and i noticed with the lower octane here in indiana its 87 and max is 92/93/94 depending on where you go to get fuel (gas america max is 92 speedway max is 93 sunoco max is 94) today i drove over 120 miles in my 05 and burnt just over a 1/4 tank. then i drove the same route only once with the higher octane in the 06 and the gas needle went just below the "F" right between F and 7/8 of a tank.

 

What can these things handle without a tune? Can these run 91 without a tune? My bro didn't know what they could hold, he didn't know if they would run on 91 at all. It'd be nice to get some better mileage out of my truck.

 

Kicker: don't put racing fuel in your truck.. It's not the octane that will really **** it off, it's the other differences in the fuel that get it to 105 that will make the truck mad.

Mike: I agree

BigHorn: I'm not sure what all of what you said was, but the difference in mileage you got was not (significantly) affected by the octane of the fuel. Those gas gages are NOT AT ALL accurate, please don't base any sort of judgement off of that gage. If the 06 did in fact get better mileage, it would be because it has MDS.

 

you can pump 93 in it if you want...not going to do anything for you without a tune (or powerwire in the summer).

sorry for caps but this is important:
HIGHER OCTANE FUEL BY ITSELF WILL NOT INCREASE YOUR FUEL MILEAGE. You need a tune or something else to take advantage of the higher octane.

 

I plan upon running a tune on my truck with it, but if for some reason it has to be taken off and has leftover fuel in it, so that it doesn't run like crap. I'd also like to do the powerwire sometime to my truck.

 

Higher octane fuel is harder to ignite and in a sense, burns slower. You will lose power with the 105 octane.
I tried the high octane fuel in my 5.0 Mustang years ago at the drag strip. Since it is only 9 to 1 compression, it slowed the car down because I didn't need it. My car runs best on 93 octane due to the timing being advanced to 14*. The Hemi will react in the same was. Less power and economy. It does smell good though. The 105 octane may also contain some lead which will clog the injectors and ruin the cat. converters.

I saw no real difference in mileage or power between 87 and 89 octane in stock tune in cool weather. In the heat of summer, the 87 may cause some detonation which will cause the PCM to retard the timing and cause a loss of power.
With the stock tune, Myself as well as the owners manual recommend 89 octane with the Hemi engine.
I run 93 octane now with my Predator tune. I just switched beck from the 93 octane to the 91 octane tune again with the MDS on. Trying for the best mpg. Both tunes feel the same power wise and the mileage is close on both tunes as well. The 93 tune seems to get a little better mileage, but not all stations around here sell 93 octane fuel. Some are oly 92, so today I switched back to the 91 setting just incase I can't get 93 octane fuel, there will be no chance of detonation.

So long story short, run 89 octane unless you have a higher octane tune in the truck from a Diablosport Predator or SuperChips tuner.

 

^+1 listen to someone who knows what he's talking about.

 

i have the diablo predator and i have it on the 93 tune because here in texas there is 93 all around and plus i am gettin the gas for .75cents a gallon