Hemi Owners - Octane Rating?
#1
Hemi Owners - Octane Rating?
What octane do you all use in your trucks? I have used 89 all the time since I bought it new in September. I tried premium (91 here in LA and LV) for the first time this weekend and saw a dramatic performance and over all torquey feeling on the drive from LA to Las Vegas. Ever since I added the Air Raid, I have gotten this weird engine noise when accelerating in 5th gear on slight hills and really have to mash it to get it to go into 4th and often time goes into 3rd and revvs higher than I'd like. With the premium, it almost seemed to go away, but not 100%. It just felt stronger. Is this just in my head?
#2
RE: Hemi Owners - Octane Rating?
I've been using 87 Octane for driving around town and on the highway, but when I tow my boat I switch to 89. I tried 91 Octane, but saw no differnce in performance to warrant the extra cost. I actually get better mileage with 87 than with 89 or 91...Go figure! Of course I'm driving mostly on the freeways with little or no load on the truck.
#5
RE: Hemi Owners - Octane Rating?
Dodge recommends 89 and says 87 will do in a pinch. Higher octane is to prevent detonationand preingnition (knocking). Since I'm always in a pinch and my Hemi has never knocked, I always use 87. However, if I were towing I would use 89 like drdeco does. By the way, over heating can increase the possibility of knocking. I live in Phoenix and the towing package and have no problem with 87 octane.
#7
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#8
RE: Hemi Owners - Octane Rating?
The trans shifts diffrently now because the intake vaccum values are now diffrent since you have that air raid.. Im not sure of the exact cause but I know that has something to do with it. as far as the noise, its normal. I always thought it sounded pretty mean. you will notice power increase with the higher octane because your flowing more air, you need the higher octaine for the longer fuel burn. Im no expert but thats how it is explained to me. If im wrong let me know .
#9
RE: Hemi Owners - Octane Rating?
The higher the octane the slower the burn. trust me. Most engines today don't need high test. 98 percent require 87 or 85 in the mountains. Sunoco stopped making 94 octane because hardly anyone uses it today. With the newer engines that are fuel injected there is really very little need for high test. There is a sensor that regulates the fuel air ratio when the key is first turned on. This senser replaces the need to adject the fuel going into the injectors as in the old days before 1975 when unleaded was first used here in the states. In those days we had carberators that were preset.And before that when we had leaded fuels we adjested the jets our selves.
#10