durango r/t
 

I have 1999 durango w/5.9 that I've put over 150,000 miles w/ no issues other than transmission. I get on average 16 mpg on regular. I'm looking at a 2003 durango r/t. What gas mileage should I expect? can I continue w/ regular gas? I'm not too much of a hot foot. Most mileage is two lane roads, 45 to 60 mph. Any info/ideas/opinions on durnago r/t would be appreciated. thanks/jcw

RE: durango r/t
 

I have a 2000 Durango R/T. I am sure the 2003 R/T should not be much different. I am getting 12 city and 14 on the highway and that's with a light foot and travelling from 60-70 mph within the Texas state speed limits on state highways. That mpg was with a K&N air filter replacement that improved it a little. If I have no windy conditions, I can achieve 13/15. Gas mileage for the R/T's vs your regular 5.9 varies because one, all R/T durangos are running FULL TIME AWD. Two, R/T's come with higher gear ratio at 3:92, I assume your 5.9 regular durango problaby uses 3.55 or lower gear ratio. Three, R/T's REQUIRE 91 octane premium gas. But if you're always hovering around 45-55 mph speeds, I can see an R/T possibly getting 14/16 or up to the 17 possibly depending on external environmental conditions.

RE: durango r/t
 

I have a 2003 R/T. Using premium gas would kill me and I really don't think it is necessary. I have always used regular gas and things have been fine. I get about 14 mpg city and sometimes 19-over 20 highway. I have put a Flowmaster and K/N filter and also that nifty little gadget you have probably seen on TV the Tornado. As long as your foot is light the Durango will be as light as it can be as well, lol.

Good Luck!

RE: durango r/t
 

You're lucky that you are not experiencing any pinging or denotation using lower than "required" octane for your R/T. Also, I would love to get anywhere near what you get for gas mileage. You must live in a very flat area and drive below 55 mph to get those figures? I will never see 19 MPG on my R/T much less the rated 17 on highway. Then again I have not upgraded my muffler and still don't think those spacers will help because of the unique design of the 5.9 intake manifold. I'll have to experience some more to see what is making my MPG so low compared to yours.

RE: durango r/t
 

Well do not think that you are alone. I should have said rerely over 20. I have seen 21 mpg on the highway and that is about all. I am just lucky that my R/T doesn't have to push over 2000 rpms to maintain 75 M.P.H. I live in a relatively flat area but it has its hills and such.

As far as the pinging and such- none what-so-ever. My father had a '99 Ram with the 5.9 and he used Regular throughout the 6 years he had it with no problem at all. I am not sure if our engines are different but I never had a problem. Did you experiment????

RE: durango r/t
 

Now that is very odd. Your engine RPM's don't go over 2000 RPM's to maintain 75 MPH???? Two things I see here, either the 2003's 4 speed tranny is geared different especially with a much taller over drive gear, or your Durango is not running on 3.92 gears. At 75 MPH, my engine is running around 2200-2300 RPM's. My max speed is roughly 65 MPH at 2000 RPM's. That is my setup on my 2000 R/T.

As far as using Regular unlead on my R/T? Yes, I have used it ONLY ONCE. I would never do it again. I did it once only out of stupidity of miscalculating how much gas I have left to make it to the next fueling station and that fueling station did not have the premium 91 octane required by my R/T. The Durango just choked on that 87 octane gas. Luckily the fueling station had some 107 octane boost to raise the octane so my engine won't spit and sputter.

There are lots of Durangos and RAM's that uses the 5.9 engine and they run on regular fuel. Only the R/T models require the premium 91 octane because Chrysler re-tuned the computer programming more aggressively. Basically we gained an additional 5 HP and 10lbs of torque over a regular 5.9. Chrysler's computer tweaking required 91 octane gas for the additional gains.

Based on your statements, I hope you did not get a regular 4x4 Durango with a 5.9 and have the R/T's badging on it? I seen regular part-time 4x4 Durango 5.9's with lower gear ratios around 3.55 gears I think that can achieve those MPG numbers you mentioned.

RE: durango r/t
 

LOL, no, the VIN has been pulled quite a few times! But at 70 I am right under 2000 RPMs. As far as the Premium octane debate, two dealers have told me the same that it was perfectly fine to use Regular. I have been using it for about 6 months with no problem at all and I am damn glad I am not having the problems that you guys are having because filling this up with Premium would be very costly!!!!

RE: durango r/t
 

I hope someone can answer the differences on the transmission from the 2000 and 2003 Durango R/T's???? I would love to be hovering at 2000 rpm's at 70 mph!!! I can definitely see some MPG improvement there. Currently I am hovering around 64-65 mph at 2000 rpm's.

RE: durango r/t
 

My 2001 R/T seems to be somewhere between you two guys... 2000 RPM's gets me just at about 70... I had my Speedo Calibrated by the Auto Club so I know it is accurate, I do not know how accurate the Tach is though... I thought maybe the overdrive was the difference but if I take that off I jump from 2000 to just above 3000...



[IMG]local://upfiles/8627/5453C7680FBA4E8B840126C25BDAB102.jpg[/IMG]

RE: durango r/t
 

Card fan,

Looking at your pic, your are just above 2000 rpms at 70. Same for me. With my Needle directly on 2000 rpms, it rides on 64-65 mph. If it goes to 70, I will raise it up just little bit more, exactly at the position of your tach. As my gauges are the 2000 model which has an additional line spacer between the speeds, I would estimate my tach to be around 2100-2200 at 70 mph. 2300-2400 at 75 mph.

I'll take a pic of my gauges going at 70 mph at post it. My speedo has not been recalibrated so it just has the OEM settings.

RE: durango r/t
 

OK, now you guys have me confused. So far two dealers and about 5 different credible websites have informed me that the R/T does NOT require premium gasoline. They all said that regular unleaded is fine.........what is the deal??????

Here is one of the sites...

http://www.autobytel.com/content/res...andardFeatures

RE: durango r/t
 

If autobytel is correct on the hp/torque specs, then yes, it is using regular unleaded!!! Only 245 HP/335 lbs of torque.

My 2000 R/T is the first appearance of the R/T package for the Durango and my HP specs show 250 HP/ 345-350 lbs torque but requires premium fuel. Because it uses the retuned computer to get the little added power.

Here is the link information for the 2000-2001 Durango R/T

http://www.440magnum-network.com/inf...urangort.shtml

It did not specify Premium or Unlead. But my 2000 R/T manual says premium fuel required. When I open my fuel door on my R/T, it has a yellow sticker strip with red letters stating in plain english "PREMIUM FUEL ONLY"

Maybe the later years 2002 or maybe 2003, they tuned down the R/T and not require premium??

Can anyone confirm?

RE: durango r/t
 

mine is the 2001 and everywhere you could possibly see mention of fuel usage, it says Premium Only... In the book it says 91 Octane Minimum...

I don't get great gas mileage though... I average about 13.5 MPG and all I do is easy highway driving.. 70 - 75 MPH 68 miles each way... Fresh Tune Up and Cold Air intake still just under 14, never could get over 12 without the intake..

RE: durango r/t
 

we just bought a 2001 R/T, but it doesn't mention anything about premium fuel in the fuel door. I always thought you had to run premuim since I had a Jeep GC with the 5.9 and it required the 91 octane. I put Plus/Midgrade in the R/T last time I gassed up, and no pinging or rough running. Maybe we're just lucky, I dunno. The manual doesn't mention premium either.

Mileage blows on ours, overhead dealie says 13ish, but I don't trust it. I'll probably drop in a K&N filter soon to help out.

RE: durango r/t
 

This is so non-consistent on the R/T's that some does not seem to require premium, and some do.. Could it be because it is in a particular geographical area that premium may not do any good on performance?

I am from the Texas area? Cardfan? as the two of us seem to be the only ones that have a written note in the manual that says "PREMIUM" only??

RE: durango r/t
 

I finally took some pics of my 2000 cluster to show you my speed/rpm range. But I do not know how to put attachments on this site. HOw do you add attachments?

RE: durango r/t
 

I think I figured out how to attach files. Here goes.




[IMG]local://upfiles/1043/BA025CC742864C0F908917CEDD84F6E9.jpg[/IMG]

[IMG]local://upfiles/1043/6CE28EA9E12D4D1E87EE7304891B612A.jpg[/IMG]

RE: durango r/t
 

Yeah I know for a fact my truck does not have to push that hard to get to 70mph. As far as the geographical areas and the gas subject goes, my truck was purchased in High Point, NC and it does not mention premium at all. My cousin who owns a 2001 R/T and lives in Jersey has the same deal, no mention of premium at all. I guess we just lucked out...... [sm=smiley21.gif]

RE: durango r/t
 

I gues in some geographical areas, premium is not required? I know that in Denver, their Super unleaded is rated like 89 octane. I guess it is because they are so far up in altitude that premium octane would be a waste of money??

Here in Dallas-Fort Worth, Premium Octane ratings are 93 and unleaded is 87 octane. Midgrade is 89.

RE: durango r/t
 

hey guys,

i currently drive a 99 dalota r/t with the 3.92 gear and average 17-18 on the highway at 75 mph. I drove that from NC to TX and it got the same all the way there and bck.
Also my truck says nothing about having to use premium fuel at all but i do use mid grade here in NC (89) and no pinging or detno. i have flows and a custom hand built air intake. I run about 2200 rpm at 70 mph. So i gues where all a little different -lol

B-Rad
99 Kota R/T

RE: durango r/t
 

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?

RE: durango r/t
 

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.

RE: durango r/t
 

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.

RE: durango r/t
 

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.

RE: durango r/t
 

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

RE: durango r/t
 

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.

RE: durango r/t
 

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...

http://www.cardinalpc.com/forum/post_dman1.jpg

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

http://www.cardinalpc.com/forum/post_dman2.jpg

And the manual cover...

http://www.cardinalpc.com/forum/post_dman3.jpg

RE: durango r/t
 

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?

RE: durango r/t
 

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.....

RE: durango r/t
 

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....

RE: durango r/t
 

Your engine will not get Addicted to a fuel - it is a mechanical piece of metal, it has no emotion and no abilty to get addicted to anything...

An octane rating is a calculation that determines a point of ignition, a higher rating means that it will resist premature ignition (typically referred to as a knock or ping). An engine that is tuned for a certain detonation or ignition point should have a fuel that is matched for the set point. Many factors can change this point as well, such as altitude or temperature. Typically in the colder months or when pulling lighter loads the benefits of using the premium (higher octane) fuels won't even be realized.

In this case, obviously the 2001 model was tuned to ignite at a point above higher than the resistance point of both mid-grade and regular unleaded fuels... I am sure that the changes to the ignition system, or the settings on the ignition system, would be minimal in order to have detonation occur at a lesser temperature, allowing the use of all grades (which apparently Dodge did on differing model years)

RE: durango r/t
 

Ok, I am not an idiot, I was just making a statement and I wish I had the old owners manual. It stated something like if you continue to use premium fuel when you may have to keep using it or when you go back to regular you will experience pinging or knocking....maybe it was my 98 Dakota...anyway nothing to argue about here, it looks like they finally fixed something.

RE: durango r/t
 

I did not mean that to be confrontational or anything, and I also did not mean to imply that you were not intelligent... I guess it did come across that way, my apologies... ;)

RE: durango r/t
 

No problem....all is well. No matter what, I bet there is not a Durango owner out there getting "good" gas mileage. I bet we can all agree on that, and if you bought one hoping to (as it has been stated before) you made a big mistake. I hope all of us Durango drivers can continue to drive our beloved vehicles due to gasoline prices.

RE: durango r/t
 

I wonder if the premium fuel it only applies to the years 2000 to 2001 or 2002 because of the recalibrated computers to give you that extra negligible horsepower/torque? I think for those of you that do not require the premium fuel, it could be that Dodge just stuck in a standard 5.9 without the re-calibrated computer to get you that extra 5 horses and 5-10 lbs of torque???

At this stage with fuel prices going up, I would like to deprogram my computer to not use premium unlead as the tiny hp/torque increase does not any difference in performance.

RE: durango r/t
 

Man , you do tach a little high, I tach at 2000 rpm's at 80 mph. I will post pic soon.

I think some of the variences we see are due to different tire sizes.

RE: durango r/t
 

Digitoxin,

I posted a little earilier on this thread about tire sizes affecting the Tach to speedo relationship and it does not change it at all. The tire size will only change the relationship between the speedo and the actual speed you are travelling. The relationship between the Tach and the speedo is govened by the transmission and the gear ratio of the axles. Changing to a taller tire for example, you tach and speedo will still remain the same, but your actual speed will be increased. The same applies to going to a smaller tire. Tach and speedo remains the same, but your actual speed will be decreased. I know from experience as I got ticketed and was able to talk my way out of it in court when I showed the judge of my very recent tire change receipts. I was doing 65 on a 60 limit and got ticketed going 71 on a 60. This was on my Toyota 4WD. I changed out from a standard truck tires to 31 inch offroad tires. My speed and tach relationship remained the same. My speedo was set on 65 but I was actually doing 71 according to the trooper's radar.

My best guess to these variances is because later models of the Durango R/T's may have a different transmission or possibly a taller overdrive gear. All Durango R/T's defaults with 3.92 axles so this variance must be within the transmission gearing itself.

This also explains the variances in gas mileage for differnt R/T owners as well. So far, I was able to increase my gas mileage to 12-13 city and 14-15 on the highway by using K&N stock filter replacement and going to the Champion double platinum spark plugs and keeping a very light foot and keeping my throttle body clean every 3 months by spraying B12 carb cleaner to remove some of the very light gunk build up on the throttle plates, etc.

I would bet my MPG may be 1-2 mpg's better if I had the taller OD gear or whatever to get my tach down to below 2k when travelling at 70 mph which is my cruising highway speed at current Texas highway interstate speed limits. Now Texas as moved the speed limit 80 mph on some interstate roads starting 01/01/2006. I don't think I want to wind up my Durango that fast as my engine speed may be hovering around 2500-2600 rpms much less sucking away any advantage I get on mpg's! haha

RE: durango r/t
 

If you took it to the extreme, and changed the tire size to, say, a little red wagon wheel, the tac and speedo
would have to be different. A average tire size change usually has a 3, to 6 mile an hour change. The change
in the tac to speedo may be less.

To determine your vehicle's engine rpm with its present tires, simply measure the diameter with a tape measure. If the tires have a convex tread surface, be sure to allow for it when you measure them.

RPM x Tire Diameter X 336 = MPH
Drive Ratio x 336


Engine RPM at 60 MPH

Ratio 31"Tire 32"Tire 33"Tire 34"Tire 35"Tire 36" Tire
3.08 2000 1950 1875 1825 1775 1725
3.23 2100 2025 1975 1900 1850 1800
3.31 2150 2075 2025 1975 1900 1850
3.42 2200 2150 2100 2025 1950 1900
3.54 2300 2225 2175 2050 2000 1975
3.78 2425 2375 2300 2200 2150 2100
3.90 2550 2450 2375 2300 2250 2175
4.10 2650 2575 2500 2425 2350 2300
4.27 2775 2700 2600 2525 2450 2400
4.56 2950 2875 2775 2700 2625 2550
4.88 3175 3075 2975 2900 2800 2750
5.12 3325 3225 3125 3050 2950 2875
5.38 3500 3400 3300 3200 3100 3025

RE: durango r/t
 

You are correct as you are basing this fomula on true actual MPH. Not what the MPH is reading from the speedo. I am just stating the relationship of the speedo and tach will always remain static as nothing has been changed on the tranny itself. Example, if you were staring at the speedo at 60 MPH, the tach will say 2000 rpm's. Changing tire sizes will not change this relationship. Changing tire sizes will change the relationship of the actual MPH and the MPH reading on the speedo. This is why owners must recalibrate their speedos if they change tire sizes big or small enough to make a major impact on the accurate MPH reading on the speedo.

So on my Toyota, after I have replaced my regular tires with 31 inchers and barely talking my way out of a ticket, I had to go to a speed shop and have my speedo recalibrated to adjust for the 31 inch tires. After the speedo is recalibrated, this changed the relationship of the tach to the speedo and the new speedo reading now shows I am running at lower rpm's using the bigger tires. This scenario fits your formula now that my speedo reading is showing accurate MPH.

If you have doubts, try it yourself, go change out your tires on your D. Don't calculate what your true MPH would be using your fomula. Most users that changes their tire sizes aren't aware that their speedo is not accurate any longer. This is why they get pulled over for going too fast and argue with the cops that they weren't speeding. You'll see the speed and tach relationship remains the same. Only your true MPH will change.

RE: durango r/t
 

Here is my speed to tach readings. REAR END : option code - OMD=3.55 gear ratio
option code - OSA= anti-slip

http://www.geocities.com/digitoxin65/tempD_cluster2.jpg

http://www.geocities.com/digitoxin65/tempD_cluster1.jpg