switched to 89 octane for my 2004 dodge RAM 2500

[eb145]

I wanted to get a little more power out of my 5.7 L Hemi 2004 Dodge RAM 2500 4x4. The truck worked kind of hard pulling my TT up steep hills and I am not over any of my weight ratings - although pretty close to the GCWR. Tow/Haul mode helped but doesn't seem to get it quite right.

So I read about this topic on various forums (including dodge truck forums), and it turns out the simplest thing was to try 89 octane gasoline for a couple tankfuls.

For me, the switch definitely helped. Going up hills on the way back from my 350 mile round trip this weekend was definitely better.

In my case, Dodge recommends 89 octane, but it can run on 87 octane. Now I know why 89 octane is recommended for my truck - because it works better!

I was thinking of changing axle gears but that is expensive (4x4) and I was thinking of getting an engine tuner to get more power, but they are not very effective with gasoline engines - unless you get a tuner that is set to 91 Octane (but then you need to burn 91 octane). That is how I learned that the truck comes tuned for 89 octane but the computer can "deal with" 87 octane but reduces performance.

Ed

[DHDB]

....and use a good fuel.

[DHDB]

Just an idea that worked for me:
(I had a 2500 Ram QC w 4:10)
Prior to towing, I would pull the "PCM Skip" fuse and clear the PCM computer. This computer "learns" how you drive and adjusts valve timing and all sorts of things to allow your engine to run efficiently. If you clear this fuse, your engine will run with the default settings in the computer. I would suggest you read about it first and then try it. You will be surprised by the "wake-up" your engine gets.
This is by no means a tuner or programmer. It is just about making the best of what you have.
To clear the computer, locate the fuse and pull it out. Turn key to the on position (do not start). Wait for all chimes to stop. Turn key off and then reinsert fuse. When you start the engine, it might run rough for the first 30-45 seconds. Take it for a "spirited drive". You should notice a difference as it shifts. It should feel stronger.
Some people might not agree with these comments, but whatever.... I do know that it worked for me. Good luck.

PS-The 6 speed transmission in the newer Hemi is awesome!

[mileshuff]

spadoctor wrote:
sounds like a poor design to me. No excuse to design any motor to need more than 87 these days....just look at Ford and Hyundai vehicles

To gain more power engines are designed with higher compression and advanced timing. Both require higher octane. Sure you can make an engine run well on 87 but it will not have the performance that can be gained with an engine designed for 89 or 91.

[eb145]

OP here to report back on observations from more trips this summer.

I am now convinced that my truck doesn't like Shell gasoline. Shell gasoline just doesn't work very well in my 2004 Dodge Ram 2500 5.7L Hemi. I have tried Shell 87, 89 and 93 Octane and they all have the same problem when burning in my truck. There is a Shell station 1/4 mile from my house so that is the easiest place for me to fill up and is where I used to get most of my gas for the truck.

When I burn Shell gas (from maybe 4 different Shell stations in Maryland and New Jersey - including the one 1/4 mile from my home) my truck has the same problems. The problems include noticeably lower power when towing, running at higher RPMS when towing, exhaust smells like gasoline sometimes and the truck just seems to struggle more when towing. It is really weird that sometimes it seems like the gasoline is not burning all the way and I smell hot gasoline fumes in the exhaust.

When I use any other brand of 89 octane gas my truck runs smoother, gets more power at lower RPMs and the exhaust doesn't smell like gasoline.

From other reading on the internet it seems that the major differences between different gasoline brands are the additives and detergents that are added. My guess is whatever additives that Shell uses don't agree with something in my truck.

Again, my truck is a 2004 Dodge Ram 2500 5.7L Hemi. It has about 80K miles, is well maintained and passes Maryland emissions inspection. I bought it used in 2006 with 32K miles on it.

Ed

[eb145]

OP here.

back from a long 4th of July camping trip. About 600 miles round-trip. I am starting to believe different brands of gasoline might be different (at least for my truck while towing). Or some stations are selling 87 Octane as 89 or 93 Octane (kind of hard to believe this happens much)

Here is what I noticed about my recent gasoline purchases for my truck (2004 RAM 2500 4x4 5.7L gas Hemi). These are my personal observations primarily from the experience of maintaining either 55 or 65 MPH going up hills on interstate highways in mid-atlantic area as well as starting from a full stop.

- Shell 89 Octane didn't seem much better than 87 Octane. This was from the Shell station near my home in Maryland. two different times.

- Shell 93 Octane didn't seem much better than 87 Octane. This was from a Shell station in New Jersey. (late night, low on gas, 5 gas stations in a row were closed, finally an open station but it was a Shell station, so I figured since Shell 89 Octane wasn't working for me, why not try the Shell 93 Octane.)

- Sunoco 89 Octane worked very well. Smooth power on the hills. Easy to maintain speed going up hills. Real nice ride.

- Rutter's 89 Octane worked well also. But not quite as good as Sunoco 89 Octane.

These are very unscientific observations.

I'm just wondering what's going on with gasoline and my truck. I got some more learning to do about gasoline and performance in my truck. I'm an engineer so this could be fun figuring it out.

Ed

[dclaarjr]

To the OP.

Tuners for gasoline engines are not as bad as you think. The trick is to have someone who knows how to tune for your specific needs write tuning programs you can load. The tune ups you get from the companies that build the tuners are very generic and do very little. They don't want to be sued when junior takes the car out and breaks something running it too hard.

I have a tuner for my car. I'm a certified mechanic and know what I'm doing so I used it to write my own tune ups for my car. I wont go into details, but with nothing but tuning, I was able to take a second and a half off the cars 1/4 mile times at the drag strip without any other mods at all.

[BenK]

spadoctor wrote:
sounds like a poor design to me. No excuse to design any motor to need more than 87 these days....just look at Ford and Hyundai vehicles

Not at all and here is the main reason...today's computer controlled
everything has the computer sense higher octane fuel, so it can and
will advance the ignition

That will then have more power developed

If poor octane fuel, then the computer will sense knocking and phase
back or reduce advance. That will be less power

[md2lgyk]

If you can find it, gas that does not contain ethanol will improve performance as well.

[spadoctor]

sounds like a poor design to me. No excuse to design any motor to need more than 87 these days....just look at Ford and Hyundai vehicles

[Dave_Mck]

If you have a Hemi you should be using 89 octane at all times.

[BurbMan]

DW has the same engine in her 05 Magnum and has used 89 from day 1 when the car was new. Here's what it says in the owner's manual:



Note that 87 is only recommended for the little 2.7L.

[Vanished]

I also usually tow with 89 and drive with 87..

[eb145]

Jim,

Yeah, I just wanted to pass on my experience. I was surprised that I noticed a significant difference in my towing experience after switching to 89 octane. For my truck.

I thought I'd pass the information to others that might be looking for some extra power while towing. Check your owners manual to see what octane is recommended.

Ed

[Jim-Linda]

It sounds like you have the answer already!!

Jim