Happy Holidays!

A couple weeks ago I filled up with 87 octane(Holidays caused a $$ pinch), Since then I can hear a very faint knock or ping only at idle speeds(under 1000rpm).
I'm about to fill-up again, this time with 89+ octane.
Does the computer & engine constantly adjust for knock & ping automatically?
What determines this adjustment? By miles, gallons, vibration or successful starts?
Magnum has 7k, I think it's broken in by now...

I need some schooling....Thanks!

 

It will pull timing when he hears pinging from the knock sensor, but it is after the fact.

 

I use 89 octane in my RT all the time, with over 14,000 miles on it now, no pings at all.

Bob

 

If you are hearing pinging at RPMs below 1K, please confirm that this is under heavy load. If it is at no load, it is not pinging (knock), and the noise is caused by something else.

If it is under load that you are hearing the pinging, then a switch to a higher octane fuel "should" solve it. But, I would also talk to the dealer, since the knock sensor should be adjusting the ignition timing constantly to eliminate the ping ,even when using a fuel lower than the recommended 89 octane). You may hear one ping or so, before the computer does it adjustment, but even that is rare. If you are hearing many pings under load, then go to the dealer for some help (and stop causing it to ping, because you can be doing damage)!

I am assuming you have the RT Hemi engine when I say this. If you have either of the V6 engines, then I think 87 is the recommended octane and it should not ping at all.

Plasticman

 

I use 87 or 89 for most of my daily winter driving. In the summer when im hotrodding it i use premium. Havent noticed any differences with either and in warm weather, I drive all the time with A/C off and windows open. I even tow a car trailer with no ill effects.

 

If you're at altitude like me (2800 ft. elev.) you can easily use 87, and in some cases (above 4500 ft.) even 85. I've used both with no pinging or other ill effects. My mileage is better with 87 than it is with 89. I've used 85 at the higher elevations and also got good mileage with no ping. I've been using 87 almost since new...17 months.

 

The lower the octane the better the fuel milage. But you have to use a high enough octane to NOT ping or damage will occur. Lower octane fuel has more BTU's of heat / energy. That said you will also get more power from a lower octane gas, as long as you don't ping. Always use the lowest octane that doesn't cause a ping condidtion while under load, you will get the best fuel mileage and the most horsepower & torque. Just a side note, ethonal mixed fuel has even less BTU's of heat energy for the same octane gas. So I try to stick with a fuel that has zero ethonal for the best fuel econ and power. Emissions be damned!