Then you more then most know the difference between preferred and recommended, dealer and engineer/manufacture. .

 

The engineers at Chrysler clearly state that 87 is acceptable. To me acceptable means you can run it in the truck. There is no warning not to use it, and in fact the engine was designed to meet all of it's requirements on 87, otherwise the feds (emissions) and their lawyers (warranty) wouldn't allow it in print. I don't get it where acceptable is debatable in it's definition.

 

What ever. Manual has a BIG 89 when you open the page. Says optimum performance. Run water if it works for you.

 

I'd run some of your bitterness if I could figure out a way to get from your posts. Too bad you can't hold a civilized discussion.

 

What ever.

 

87 can be hurtful to performance if there is knock happening, so at that point 89oct would be a benefit and give you better mpg's.

LOTS of 3rd Gen guys who have ~80kmi or more have blown/damaged their engines due to detonation from using 87oct. The ringlands on the Pistons used in the Hemi engine are of Nascar style and are very close to the surface. Too much pre-det and this eats away and evetually breaks the ringlands off causing major damage. Everytime your engine has pre-det, little pits form in the surface of the piston head. It's far more damaging than people realize.
Also, lots of guys who have changed their heads or replaced gaskets have noticed lots of pitting as well, so they caught/sen the issue and started using higher octane in time.

You 4th Genners haven't heard much of this because the majority of the crowd has low miles since its a newer truck.

Do what you wish, but I wouldnt put anything lower than 89oct in my ride. If your pumping from a very busy station, you might be fine with 87oct, but from a small not very busy station use 89oct. Smaller stations have gasoline that sits and goes bad before you pump. Especially 10% Ethanol blends as that blend gasoline goes bad within a few weeks. When Isay bad, I mean loses it's octane rating. 87oct in a few weeks will drop down to lik 83-85oct depending on the situations.


Standard break-in is drive it like you stole it..lol Seriously though, you want to vary the rpms and not stay at one rpm for too long. So, on the highway, dont keep the cruise on and maintain a steady rpm.

 

While I agree with most comments about using 89 instead of the 87, I have make the following points.

1) This is a 4th gen forum and not one person on this or other forums has had engine issues with 87 gas. Many here have lots of miles on their trucks.

2) The folks that run 89 exclusively really have no experience with running 87, thus their opinions are not based on "real life experiences" with their 4th gen trucks.

3) If Dodge didn't want us to use 87, it would have been easier to just omit that it is acceptable. Just say we have to use 89.

4) As a engineer, I'm familiar with meeting requirements. The 4th gen hemi had a requirement that it run on 87. The engineers either met this requirement or not.

5) Modern engine management techniques have programmed schedules on timing and fuel delivery (tunes). They store the 87 tune in the memory and use it when they detect that the engine needs it. It's not like it tries to keep up with pinging every stroke.

6) There are many other factors that contribute to pinging, not just the gasoline rating. A lifted truck with large tires will work harder and is more susceptible to pinging, especially going up hills.

Anyways, we've again managed to beat a dead horse.

 

The engine management does keep up with ping every second or faster and adjusts according. They have done this for over two decades. I use to hook them up to a scope and could tap the engine block with just a screw driver tip and watch timing jump retard at the very instant of the strike. Thats how I checked knock sensors back then. That was 20 plus years ago.. Just what do you think they do now? I've run 87. Couple times on purpose,couple times by accident. It doen't run as crisp and as someone else posted about less fuel mileage. I just wasn't sure if it was driving conditions or the octane. I will agree with you on beating a dead horse. I'll say again you can run whatever you want. I know what the word preferred and recommend means and why.

 

I'm done beating a dead horse. Peace

 

Being that its summer time and in the 90s i prefer and know mine rus better with 93 octane if it were cooler OAT then using a lower octane may be fine,