Casey's sells 89 octane for .02 more than 87 octane (regular).

Think it matters?

 

for .02 it's worth it!! but if it's .10 it's not!! higher octane isn't always better, some studies are out that say if you run too much octane it can and will actually hurt your performance and gas mileage, but i have no idea where the limit is, but i would buy it for .02!!

 

My 03 5.9 manual says to run 87 only. Higher octane will hurt mileage and performance. Straight from my Ram Manual.

 

You only need higher octane if'n your engine knocks.
No Knock - No Need

 

I have run several tanks on 93,89 and 87 octane. and anything over 87 was giving me less MPG and no difference in throttle response. I actually gained MPG with the 87 Octane......go figure.

 

I'll through another variable into the mix.

Higher octane fuel burns less efficently thereby increasing the amount of fuel dilution (from blowby) going into your engine's oil. This is bad for your oil, and bad for your engine. The fuel breaks down the oil faster.


Bill,

 

As you Hemi owners out there know, the manual says that you should run 89 octane for the best performance, but 87 is acceptable. If there were only .02 cents difference in price, I might be tempted to try it. As that's not the case around my parts, I will continue running 87, which is the only thing I have used, so far, in my Hemi.

I was interested in this thread though, to see if anyone out there had found any difference in MPG or performance.

 

I also have a 2004 hemi 5.9. I purchased one tank of 89 octane and the truck did not give me better performance but it did give me less mileage for that one tank. Go figure.

 

I have a ? then I have a 1998 5.9 limited grand cherokee and it tels me that I should only put premium in the cherokee. is there a reason why

 

Hi all, I purchased my Ram 1500 Hemi 2004 on March 25, 2004. Since I've had the truck I have been burning 89 octane as in my ex-Ford F-150. I live in California and the price of fuel is out of control. On my last two refills I filled the truck w/87. To my surprise it appears the the truck seems to be loose (faster) and the so called Hemi noise, the dealer said was normal, seems to have dissapated. I guess the concensus is that there is nothing wrong with using 87 Octane. [8D]