I'm assuming you are talking about 89 octane when you say higher octane. If you are running 91+ octane in these trucks without a tune then you are for sure throwing money away.

 

Perhaps...I have no empirical evidence to prove either claim; mine or yours.

 

I'm about 90% sure i read in the truck's user manual where it almost explicitly says that using gasoline with an octane rating above 89 is pointless and a waste of money because it will not provide any additional power gains. I will double check next time I get in my truck and report what i find.

 

It says that and I believe it says that using anything higher than what is recommended it could cause damage to the motor.

 

I am assuming that since you paid extra for the Hemi, you want all 390 horses available. Use 89. If not, then use 87. But then why did you pay extra for the Hemi? Makes no sense. For the little extra it will cost to fill up with 89 over 87, it's not worth it to sacrifice the power. We're talking $3 per tank. If that's gonna break the bank, then you probably don't need to be in a brand new $40,000 truck anyway. I'm not trying to sound like an ***, it just makes no sense to worry about $3 a week.

 

Or you could move to Iowa, use 89 octane, and save about $3 a week since 89 is 6 cents cheaper than 87 octane here.

 

Is that true because I've been putting in sunoco ultra 94 in my truck, if thats the case I'll just use 89. I've always used ultra 94 in the cars i've had with V8's so it's just a habit.

 

No, higher octane is not going to harm your engine, its just unnecessary in our trucks.

 

I've been using 89 for the last few tanks, I notice no difference, going back to 87 next fill up.

 

no dyno that i've seen has said that 89 gives more ponies than 87. In fact, the only dyno with 87 that I've seen has been from a predator and it shows 20+hp over stock.