I'm running about the same RPM with a 5.9L SLT 4x4. Mine has 3.55 rear gears and rolls onf factory 15" rims shod with Michelin( yuk) LT 31x10.5x15 rubber. I do way more city driving now than I used to so I average about 11-12MPG over all. I get pretty good milage on the freeway all things considered but I haven't recorded an average fuel economy of greater than 12 yet. I noticed that my RPMs changed after I put in the AirAid and TBS. they dropped about 200-400+ RPM at 70 MPH

 

Hey Kensai,
What type of plugs do you use? I have 50K on my 2000 4.7 and need to change them. I too would like to stay as true to the original as possible. Thanks in advance for the info!

 

The OEM plugs that my 2000 R/T Durango used was Champion Plugs. I went to Nappa auto parts and Champion makes a special spark plugs for Trucks and SUV's so I bought those. So far, I got almost 20k on them and my last visual inspection, these plugs are still in perfect shape so I may let them run for another 20k miles.

I only have 10 payments left to pay off this Durango and then plan to do some modifications. Staying true to OEM, I will get most of the stuff people says makes a difference such as Cold air intake, etc, from Mopar's website. I want everything under the hood to stay Mopar!. Here is my priority order for modding my D after I pay it off.

1. Hypertech programmer
2. Mopar Cold air intake.
3. Fastman 52mm Throttlebody.
4. Catback Exhaust with dual outlets. (GSM true duals too expensive). will get a 3.5 inch single pipe plumbing to get nearly same flow as dual pipes.
5. M1 intake.

I thought about headers, but I had bad experiences with headers as far as longevity goes. They never seem to last longer than a couple of years before the headers spring a exhaust leak. This is from various manufacturers. Maybe the Mopar brand may last longer? If budget (wifey) allows me, I would love to get a supercharger kit bolt on.

 

Thanks for the info Kensai. It's ridiculous how indecisive I am with items for my D. I was either going to go with Champion or NGK. I didn't want to take as much time figuring out which plugs to go with as I did with tires!
I'm jealous - I'd love to go with a few mods myself, but hubby won't allow with baby on the way. It unfortunately works the other way too

 

My list is still a wish list as I still need approval from my banker (wifey)!

After it is paid off, realistically my wife may let me buy some things that make practical and economic sense especially with gas prices as high as they are. Problaby end up with getting a Mopar cold air intake and Hypertech programmer. I hope a cold air intake will add another 1-2 mpgs. Already my K&N stock filter replacement gave me another 1 mpg improvement. Then the hypertech programmer will enable me to use regular unlead instead of premium gas required for R/T's that I am currently paying for! Hopefully if I can even get a partial claim from hypertech on MPG improvement, I can get a total of 2-3 mpg improvement using these two upgrades.

As you have a 4.7 instead of a 5.9, you may need to go with a superchip programmer as hypertech does not make one for a 4.7. Don't consider buying those piggyback chips as most dodge owners confirmed that those chips do not work permanently. They say the main PCM can compensate for the piggyback chip and eventually revert the settings back to stock.

 

Just curious, How can adding a Airaid and TBS change your RPM setting at 70 MPH?????????? RPM's and speed are usually gear driven and the PCM can allow for minor adjustments that you can change such as tire sizes, but never seen these changes caused by CAI and a TBS.

 

Because the engine is not working as hard to reach that speed it won't need to work hard to hold it, you know overdrive? I averaged that in my s10, I haven't gone over the mountain in the durango yet but next week I may to get some stuff and I'll let you know

 

I know overdrive, and overdrive is a physical gear that physically changes the rpm/speed ratio. I am enquirying how a CAI and a throttle spacer can physically change the rpm/speed ratio.

To look at it another way, based on your theory, if I were to go and buy fastman's biggest throttle body so my engine can breathe more air and say make a huge 10 inch diameter CAI intake, I can bring down the RPM's even further? I don't think that is gonna happen.

RPM to speed ratio is physically governed by gears, has nothing to do with CAI and throttle spacers and the like. You can make all the mods to the engine all you like, but you will not be able to change the rpm to speed ratio unless you modify the gears on the transmission and gear ratios at the rear axle.

Also, changing the size of tires can affect rpm/speed ratios.

 

Hey Kensai,
Thanks for the info! I already replaced the filter with the K&N - I get about 1mpg more now. I wasn't too interested in changing any of the programming, but I would love to replace the exhaust and add on a cold air intake. Ah, but the only upgrade I'll be doing any time soon is adding a baby seat to the back!
Here's hoping your wife, er, banker will let you do what you want with the big D![sm=icon_cheers.gif]

 

I saw it for myself. After useing the SuperChip Programmer to the highest
performance settings, and running Premium fuel, I noticed a difference in
the RPM's and shift points, when going up a grade . The extra power my
K&N cool air, functional hood, and programmer combined gave me, the engine
does not have to tach as high to drive up the same grade now.

At cruise speed the RPM's seen a little less too. Before when I let off the gas at
highway speeds, it felt like the brakes were slightly dragging, Now, it wants to coast
more.