What will 87 octane do to the engine? i've been using 87 for the 3 yrs that i had it,but as of yesterday i am using 89 from now on.. hope i didnt damage anything! truck has 79,000 miles on it,bought it with 42,000 three years ago.. but dont know what the previous owner used... its a 05, 1500 with 5.7

 

87 cam allow predetonation.. aka ping.. its when heat in cylinders coupled with compression allows the charge to fire before the piston reaches the top of its travel.. or, its when it explodes rather than burns.. the octane compound of chems actually is a inert compound.. it doesn't go boom or burn, but allows the ignition of the a/f charge to happen more predictable and controlled..

On a higher compression engine, pre-det is a very bad thing.. it can take out piston, rods, bearings, or cranks.. its not safe on a lower compression engine either, but a higher has less margin for error..

 

* can allow.. my phone hates me..

 

As Drew states, the higher the compression of the engine, the higher the octane requirements. Despite the fact that Chrysler takes the stand that 89 is highly recommended but 87 is ok, the majority of engine failures in the Hemi show unmistakable signs of pre-detonation and MOST of these owners admit to using 87 octane fuel on a regular basis.

Since seeing a good deal of evidence, I've taken the stance that EVERY Hemi engine owner should use 89 octane with the stock tune. There are tuners that retard timing and do other things in the engine to "de-tune" it so that 87 octane fuel is safe. Using 87 octane fuel with a tune specifically written for this fuel is fine - but stock you should be running 89 octane.

Does this mean that your engine will explode or experience a significantly shorter life if you use 87 octane? No, but the odds of having a problem related to the effects of long-term pre-detonation will be higher. Running 89 will give your engine better performance and is added insurance for a reduced risk of engine problems and added longevity.

I know that the statement in the owners manual would lead you to believe that if your engine fails and you've used 87 octane that for warranty purposes you should be ok, but why risk the down time with an engine failure and chance that the rebuild will be as good as the engine was the day you bought it?
I've also heard first-hand from someone who did have his engine go that the dealer refused warranty repair due to "owner neglect" because the engine showed signs of long-term pre-detonation. The guy paid out of pocket for another engine and last I heard from him, he's still fighting Chrysler for reimbursement.

Is it worth the potential problems and hassles just to save $3-4 per tankful of fuel? That is ultimately up to you...

 

Thanks drew and hammer for the explanation,i rather pay a extra few cents a gallon then take the risk...

 

So now I am hot!!!! I called the dealership this morning to get an update on my truck. I ask the service section "any word yet on when the inspector is coming?" The heffer tells me oh he has come and gone. What part of "I would like to be there when he comes, to put to rest any question that he might have" didnt they understand. I am thinking that this was days ago. So my next question was "what is the deal?", oh Mr. Baum we have to wait until they make a determination as to what happened. I asked if the tech that was with the inspector was available so I could get a sense of what they were thinking. The heffer then replies "well he talked to me and said that he would go back to his office and make a determination".

I sent my son up there to talk to the sales guy that has been taken care of us in the past. They tell him to wait in the waiting area and my son said the service manager came out and said "the inspector just left and trust me we want your truck out of the bay because it is in our way, but when we find something out we will let you know".

Needless to say I am making a trip to the stealership in the morning to find out what the big secret is. Why can't someone say it was x part on the piece of **** that broke. This has been going on for 17 days and we are still sitting with our thumbs up our tails. I am getting ready to break out the yellow pages and start dialing lawyers. I feel that I have been more than patient during this whole ordeal.

 

17 days and you still haven't gotten any further in the process!? That's BS, and pretty much proves that the dealership is trying pretty much everything they can think of to try and wiggle out of fixing it on their dime.

 

Well it is the 9th of July and so far the warranty company told me that they were not going to cover the damage done. They said that it had to have been caused by the engine "ingesting water/hydrolock". So I have my insurance company on it now and they are playing patty cake with the damn thing too!!!!

If the insurance won't cover it then I am going to get a lawyer. The warranty company (CNA) sucks a$$. I spoke to a rep and he said "I see it in here and it just needs a supervisor to sign off on it, hold please and I will get one to do it". Why did it take me calling them after a week, for something that was done in 3 minutes. So when the rep told me that they were not going to cover it, I politely said "can I speak with the supervisor"? It's been over another week and about 5 calls and no one has called me yet. Lesson learned, stay clear of CNA.

 

I think you need to have the inspector personally show you signs of water in the engine, its unfair the way they act

 

By now I would be telling them that you are getting a lawyer involved and since they can't show you the signs if hydro lock or whatever else excuse they come up with then they can go ahead and explain the to a judge and let's see if he will like it when they cant or won't prove it and in the end rule in your favor an they will look like complete dumba$$ which is nothing new to them