Seems like your Dak eng/tranny closer matches up to mine as my pic shows around 2200 at 70 mph. But the 2001 thru 2003's, I guess they have a slightly taller overdrive gear and they are barely pushing past 2000 rpms at 70 mph.

I'll find the page in my 2000 manual that states premium required and take a pic of it. Will also take a pic of my fuel door that shows premium required sticker.

I am now pretty sure that requiring premium for highest performance must be based on what geographical area and altitude you live in?

 

I have a 2003 R/T 250 HP 345 Torque.....living in Canada, purchased it here also. No mention of using premium grade fuel, runs great other than mileage, no ping or knock.

 

I think we have clearly established that not all Durangos require premium grade fuel. There are a select few that have been unfortunate enough to receive some of these. It is just a case by case basis.

 

02 R/T here. Only 28,000 miles on it. No premium fuel required either. As for the RPM issue... I played with it on Thurs night. At 64-66 MPH The tach reads 2000 RPM's. At 70 it is 2200-2300. 3.93 gearing.

 

I would say the small difference you all are seeing might be the tires. They might not have the same tire height. This could account for higher, lower RPM's on the highway, and milage. I have a 00 R/T with a new tranny, headers and knock off KN unit. It only gets 13-14.5 no matter how I drive it. It got 13 towing my Roadrunner from TN a few weeks ago. It has a little lower profile tires, so it takes off fast and reads higher RPM's on the highway. I personally love the AWD vs the reg Durango. Have had both, and the R/T's are way better with weather conditions. A better G rating also side to side. Peace

 

If it is the tire height, I do not think it would change the relationship between the RPM's and the speed reading on the speedo and rpm gauges as they are geared or calibrated on the computer side. So lets say you change the tires, if you do 70 mph according to your speedo, your speed will either be slower or faster than what the speedo says based on the height of the new tire. Taller than OEM tires will result faster mph than what the speedometer says, shorter height than OEM tires will result slower than what speedometer says. If speedo is calibrated to OEM tires and you bought oem replacment tires, your speedo should be on the money on actual speed on speedo.

 

Here is what my owners manual says... (been meaning to scan this since this topic came up). My friend has the Dakota R/T and told me that his too says that he only has to use 87 octane but after having him bring his book in, he did not read the entire page... His says the exact same thing as mine does... When he saw this picture and the little "87 Octane" emblem he just stopped reading, assuming that it was fine... Dodge is lazy, they only make one maual for all model each year...



Note the "exect for R/T model" reference...



And the manual cover...

 

Just think, I wonder how your R/T durangos would perform if you were actually using premium fuel that these R/T's were designed for?

 

Just out of curiosity I peeked at my manual today and it says the exact opposite of what is posted above. It informs me that the use of Premium fuel is NOT recommended and can result in poor engine performance. I can post pics if someone really wants to see it. I was just too lazy to grab my camera.....

 

Exactly what mine says.............may harm engine. I am not going to scan it. Mine is a 2003 and that is what the manual says. Makes no exceptions for R/T. I remember something about my 2000 Durango I had with the 4.7 l mentioning that if you used premium too often that you may have to continue to use it or you will experience spark knock or something to that effect..........like an addiction. I believe myself that any vehicle would probably perform better with some more octane but I am happy with how my D goes and well the price difference and the price alone for gas right now, I don't want to start something that I have to keep up....