Better milage while using premium fuel...

Premium fuel does nothing, chip or no chip to improve fuel economy.

Mike

Why are you burning premium all the time now?

I would imagine to keep the normally pinging 318 or 360 from sounding like it's got a bag of ball bearings in it.

BDK

Well, I run mid grade in mine, but only because I used a Hypertech programmer. Prior to that I used the cheap stuff without a problem.

The truck belongs to my sister, who will not run cheaper gas in it, despite my reasoning with her that all she is doing is spending more money. I know that in certain applications, I believe older vehicles (OBDI), that chips and such may help fuel economy when using premium gas... didn't know if this was the case with late model trucks, or older ones for that matter. Thanks

Matt

Every 318 or 360 I ave ever owned (3 360's) or driven, over a dozen pinged a little, or in the case of the 2000's and 2001's a lot. I didn't buy a 2000 Ram, and that was one of the main reason.

BDK 2003 hemi Ram..

6.13 Can higher octane fuels give me more power?

On modern engines with sophisticated engine management systems, the engine can operate efficiently on fuels of a wider range of octane rating, but there remains an optimum octane for the engine under specific driving conditions. Older cars without such systems are more restricted in their choice of fuel, as the engine can not automatically adjust to accommodate lower octane fuel. Because knock is so destructive, owners of older cars must use fuel that will not knock under the most demanding conditions they encounter, and must continue to use that fuel, even if they only occasionally require the octane.

If you are already using the proper octane fuel, you will not obtain more power from higher octane fuels. The engine will be already operating at optimum settings, and a higher octane should have no effect on the management system. Your drivability and fuel economy will remain the same. The higher octane fuel costs more, so you are just throwing money away. If you are already using a fuel with an octane rating slightly below the optimum, then using a higher octane fuel will cause the engine management system to move to the optimum settings, possibly resulting in both increased power and improved fuel economy. You may be able to change octanes between seasons ( reduce octane in winter ) to obtain the most cost-effective fuel without loss of drivability.

Once you have identified the fuel that keeps the engine at optimum settings, there is no advantage in moving to an even higher octane fuel. The manufacturer's recommendation is conservative, so you may be able to carefully reduce the fuel octane. The penalty for getting it badly wrong, and not realizing that you have, could be expensive engine damage.

6.14 Does low octane fuel increase engine wear?

Not if you are meeting the octane requirement of the engine. If you are not meeting the octane requirement, the engine will rapidly suffer major damage due to knock. You must not use fuels that produce sustained audible knock, as engine damage will occur. If the octane is just sufficient, the engine management system will move settings to a less optimal position, and the only major penalty will be increased costs due to poor fuel economy. Whenever possible, engines should be operated at the optimum position for long-term reliability. Engine wear is mainly related to design, manufacturing, maintenance and lubrication factors. Once the octane and run-on requirements of the engine are satisfied, increased octane will have no beneficial effect on the engine. Run-on is the tendency of an engine to continue running after the ignition has been switched off, and is discussed in more detail in Section 8.2. The quality of gasoline, and the additive package used, would be more likely to affect the rate of engine wear, rather than the octane rating.

6.16 What happens if I use the wrong octane fuel?

If you use a fuel with an octane rating below the requirement of the engine, the management system may move the engine settings into an area of less efficient combustion, resulting in reduced power and reduced fuel economy. You will be losing both money and drivability. If you use a fuel with an octane rating higher than what the engine can use, you are just wasting money by paying for octane that you can not utilize. The additive packages are matched to the engines using the fuel, for example intake valve deposit control additive concentrations may be increased in the premium octane grade. If your vehicle does not have a knock sensor, then using a fuel with an octane rating significantly below the octane requirement of the engine means that the little men with hammers will gleefully pummel your engine to pieces.

You should initially be guided by the vehicle manufacturer's recommendations, however you can experiment, as the variations in vehicle tolerances can mean that Octane Number Requirement for a given vehicle model can range over 6 Octane Numbers. Caution should be used, and remember to compensate if the conditions change, such as carrying more people or driving in different ambient conditions. You can often reduce the octane of the fuel you use in winter because the temperature decrease and possible humidity changes may significantly reduce the octane requirement of the engine.

Use the octane that provides cost-effective drivability and performance, using anything more is waste of money, and anything less could result in an unscheduled, expensive visit to your mechanic.

MWarren wrote: The truck belongs to my sister, who will not run cheaper gas in it, despite

I used a Hypertech programmer on mine. I set it to the mid grade program, and power and mileage actually went up. Then I set it to the premium fuel programm. Power went up just a little, but not much. Fuel mileage went down. If she insists on using premium fuel anyway, might as well use the hypertech and set it mid grade. I gained about 2mpg on steady highway driving, and about 1mpg around town. The hypertech cost about $275-300. I'll let you do the math on this one.

A non believer. I have been using premium for a many years in my V8 and the only one I use 87 in is a old carbed AMC360 with 8 to 1 compression in a J20 Jeep truck. Everything else is 89 or better. (personally I think that 87 should be taken off the market because it is more trouble than it is worth and a real hidden performance killer on a hot day when your ECM has to retard the spark to control fuel knock). I have 89 4x4 burb that I bought new and when I ran it on 87 for first few thousand miles it was gutless in warm weather and prone to ping (even with ECM retarding spark some) I switched over the premium and reset base timing at 8 BTDC and the difference was night and day and been running it that way since. I can get a honest 19 MPG on hiway at 65mph with A/C on and that is on a 560 plus mile trip and one tank of fuel (40 gallon tank). On 87 the best it ever did was a little over 16mpg with A/C off on one trip on flat lands. It is very perky to drive and runs like a champ. But there are those that think they know more than automotive engineers and engine designers and that

87 is the fuel to use. We even use 89 or better in my wifes 4 banger 2000 Cherokee in summer as it will get in the low 20?s around town with A/C running on 93 (23.5 last tank) and the best it will do on 87 is about 20 or so in same usage and it runs noticably smoother too on 93 than 87.

You do understand your V8 (assuming you're driving a Dodge truck, of course) has no knock sensor, and therefore no ability to retard timing, and therefore, as Mike says, premium fuel offers NO benefit over mid-grade gasoline. And since the OP has a 5.2L V8, Mike's statement is 100% correct.

You mean like the engineers who wrote the owner's manual that states the vehicle was designed to run on 87 octane fuel?

I've only owned two. A 90 and a 92. Both pinged until I put colder plugs in. The 92 tows everything, and has most of its life. I run 87 in it and it never pings. With the factory plugs it would ping under medium power output. Give it more or less throttle and it would quit.

Al

92 W250, 360, 5 speed.

I ran 91 in my Dakota 5.2 for a while... After getting the cat replaced, I stuck with 87 and have not had any problems since.

mid-grade

It is not 100% correct and the only reason it says 87 in manual (minimum too) is because it is a sales death sentence to have 89 in manual not because it is best fuel. Youdo not that when they run EPA MPG tests that they have long used 93, not 87 when testing because tests do not require the use of 87 octane fuel. (they can do it because manuals say 87 minimum, not 87 only)

When you put in colder plug you are in effect retarding the spped of spread of the flame after ignition and reducing engine efficency. You may have think you cured it but your cure is costing you in fuel consumption and give that with today price that better fuel can be bought for a mere 2 or 3% more, way would you insist on still using the lowest octane fuel you can buy when MPG gains can more than offset the cost?

Where did this info come from? I'm interested in reading it.

Thanks, Al

Why do you think the ping stopped? By magic? "Ping" is caused by too quick of flame speed spread (speed of spread is determined by pressure and tempature of ignition source) Detenation is caused by the fuel igniting without a spark. By retarding the spark or using a colder plug to can "retard" the peak pressure and rate of flame spread in relation to piston cycle but when you "retard" combution process to control ping you loose efficency. Man I took this stuff in college when studing for a engineering degree in the late 70?s and the physics of the processes in a IC engine have not changed any, only some of the methods to control and feed it has.

The heat range of a spark plug is an indicator of how hot the tip of the plug can run A shorter thermal path to the shell means a colder plug.It has NO effect on ignition timing. A vehicle running under load CAN ping due to pre-ignition from a hot plug. It is NOT common with factory spec plugs, but has been known to happen. Changing to a colder range plug in this instance CAN eliminate the ping - and at NO COST IN EFFICIENCY OR PERFORMANCE. Changing to a higher octane fuel CAN eliminate the ping in the VERY odd instance - but only if the higher octane fuel causes the hot plug to run cooler - and this virtually only happens if the engine is on the "edge" octane-wise to start with, and "mild detonation" is destroying the boundary layer in the combustion chamber, transferring excessive combustion heat to the plug. It is VERY difficult to differentiate between pre-ignition and detonation, particularly since either one CAN cause the other - and it's very difficult to tell which came first - Kinda like the Chicken and the Egg.

If higher octane fuel does not reduce the "ping", strongly suspect "pre-ignition" due to hot spots in the cyl.Things like too hot a plug, carbon deposits glowing, or poorly fitting head gaskets "glowing" in the cyl.(or overheatred valves - or even an overheated engine - which CAN be caused by timing retarded too far trying to get rid of "ping" or "knock" caused by running too low an octane rating of fuel for the engine design.

First line of defence with a "pinging" engine is to run higher octane fuel.

I thought the ping stopped because the tip of the plug was too hot. Can you find an article about this? How do you tell ping from detonation? My trucks, both of them, had a slight knock when pulling at about 1/4 output. My 92 is a 5 speed and if it started doing it I could stuff it in overdrive and it would quit. Whatever changing the plugs did stopped it. I've towed all over the Southwest with no problems.

I appreciate your answer. I'm not trying to bust your chops, I just would like to read about it. When I first asked about this I was told the plug wires caused it and there was a TSB about some crossfire problems. Changed the wires and the problem did not go away.

Did a Google search to see if I could find something revelevent:

And lots more. None of them mention what your saying??

Al