I run 87 when I set my chip to fuel economy setting. Then when I set it to horsepower, I run 93.

I can run the lower octane on horsepower setting, but when I pull my boat, it pings a lot.

 

Personally, i run 87 but, with a big v8 does not matter what you run the needle is gonna go down quicker than you want it to.

 

Thanks everyone for the replies!

 

Using higher octane can lower your fuel mileage, in many cases. Ethanol is often used to raise the octane rating, and since it's less efficient than gasoline, your mileage will suffer. Like these guys said, it's built to run 87 octane fuel, no need for anything else. Oh, and so far as I know, ALL Wal Mart gas stations (Murphy's USA) have ethanol in all their fuel, even the 87 octane. In my suburban, I get 16 MPG using gas with no ethanol, and 14 on Wal Mart gas.

 

in NJ they are required by law to have a sticker on the pump if there is ethanol in the gas, Hess has it as do most of the name brand stations, i buy off-brand gas that doesnt have ethanol in it

also while ethanol does raise the octane ratings they were (a while back, not sure if its still true) only putting ethanol into regular grade gas.(that could have changed, i havnt looked into it recently)

 

Back when I was running a 318 in my '99 Durango, and I was towing my '01 Durango home on the interstate (70mph) I had some pinging with 87 octane. Granted, the trailer along with the '01 Durango combined were like 6,700lbs.

I'd say if you aren't towing anything, 87 octane is fine for that. Towing I would definitely run the high test.

I run a programmer now and run it with the 93 octane tune and that's all I run in 'er now.

My fuel mileage is crap either way, I get 12mpg on a good day. :lol:

 

I've never had pinging even towing over 8000lbs on 87 octane with my 5.9l.