Fuel Econmy Upgrades

[DRyder]

I have a 2004 with a 305 5. 9L automatic and I am the first to drool about after market add-ons that claim huge HP gains and such; but with the price of diesel, I was wondering what are the best aftermarket add-ons for fuel economy?

 

[AllianceDiesel]

anything that advances timing and holds the injector open longer will get you better mileage. don't believe in air intakes and stuff like that, they are just a waste of money.

 

[mberry]

Personally, I wouldn't say air intakes are a waste of money, they just generally do not produce mileage gains on their own.

Mopartech is correct though, timing is the key. I switched everything on my truck to synthetic lube of higher quality than came with the truck. RP or Amsoil in the diffs, Amsoil in the TC and transmission and engine, an Amsoil drop in air filter, and a TST PMCR on 1/1 gained me about 4MPG overall. I keep the tires inflated to around 70PSI to help reduce rolling resistance also.

 

[MickeyMiller]

Pressure box... I've run the EZ and now have a Smarty JR... got 2 MPG increase w EZ... no change with Smarty JR on 40HP setting. Will try higher settings and maybe stacking... . BTW MBerry, I previously built a 1970 800B w 392 cu in IHC, 727, 44/60, 4 tanks, full cage, engine set back 13 inches... LOVE SCOUTS!

 

[CToney]

A intake horn gave me ~1mpg. Cooler Tubz in the Classifeds if you would like one. Synthetics and a Fass help a bit.

 

[rbattelle]

Slow down 5mph. Instant fuel economy gain.

Ryan

 

[Paddy McMahon]

SMARTY set on level 3 gave me 22 mpg on a round trip to Idaho from So. Cal last week (2200 miles). Edge and Juice setting on mileage got me 18. 9mpg for the same trip a couple of months ago. Both of these setups gave me improved milage over stock which was 17. 5mpg. Average highway speeds were 65-80mph depending on the interstate postings.

 

[BGlidewell]

the stock tires lasted 20k miles. With 6 new Michelin LT M/S tires I'm getting an extra MPG. Now in addition, I'm not letting boost go over 10 and trying to keep it under 5 to see how this tank does... . with a 60 gallon tank I got to almost 300 miles before the needle moved off full.

-Rolling road-block, hyper-miler

 

[USMCBay]

I don't know why and I'm not willing to change anything - but I am getting 28. 5 to 30 mpg - "physically" not electronically. I went from Houston to Orange, TX at the border filled up there... went to Orlando, FL filled up - spent a week there - topped off before I left and made it back to Houston on two tanks.



I was coming back from Odessa, TX with a hard tail wind at the end of March and figured 31+ mpg.



I bought the truck over a year ago and put in an Edge EZ and nothing else. I run Injector cleaner through it pretty often but other than that - I have no idea what the previous owner did.



I am starting to get a white smoke - 175k miles so need to pull an injector and replace whats in it now.



Just the facts - no BS - no reason too...

 

[jtwcummins]

If you have a boost gauge keep it as low as possible for better fuel mileage. The best option for improving fuel economy is a very lite right foot and don't drive over 65 mph. My economy goes in the tank fast as speed increases.



On the 08 I also keep from lugging by using the range select to keep trans in a lower gear in slow in town driving. Also, when towing in the mountains, mostly I80 between Reno and Sacramento, I lock trans to shift no higher than 5th. That is the first OD gear. This keeps trans from doing alot of shifting and keeps the engine rpm at a more efficient level.



When driving carefully I get just under 14 mpg towing and can get 18-19 empty. Problem is it is very had to do, the 6. 7 just wants to GO. Overall I get about 1mpg less in the 08 than I got in my 97 auto w/4. 1 gears.

 

[rbattelle]

I don't know why and I'm not willing to change anything - but I am getting 28. 5 to 30 mpg - "physically" not electronically.

Wow! Can you post your fuel log during the period you achieved this? I'm curious how the trends look.

That mileage is close to what I achieve with my Honda Accord 4-cylinder.

Ryan

 

[Turbo Kidd]

Wow! Can you post your fuel log during the period you achieved this? I'm curious how the trends look.



That mileage is close to what I achieve with my Honda Accord 4-cylinder.



Ryan

Ryan, you are killin' me... . :-laf I would love to see that fuel log too. I would love to know how some people get that kind of milage. I don't want to call anyone a liar, but my real world numbers are no where close to 28. 5 + MPG. I get about 13-15 MPG around town, and 17-19 MPG on the road empty with the wind up my ***. I get between 12 & 15 MPG when towing, and that varies a lot depending on what I'm towing and how fast I'm going. These are real world hand calculated numbers. No reason to lie..... I'm the idiot that has to pay to fill the pig up... LOL!



I am always looking for ways to get the best milage i can too..... Lets face it, at $4 + a gallon it only makes sense to squeeze every mile you can. Some mods will help..... However, my heavy foot always offsets any gains that might come from that. I think the best way to optimize your fuel economy is to drive with a light foot, keep your tires inflated properly, and run with the wind.

 

[Regcabguy]

Wow! Can you post your fuel log during the period you achieved this? I'm curious how the trends look.



That mileage is close to what I achieve with my Honda Accord 4-cylinder.



Ryan

Ditto for me with my '98 Accord,5-speed A/C off.

 

[JHardwick]

I don't know why and I'm not willing to change anything - but I am getting 28. 5 to 30 mpg - "physically" not electronically.

:-laf

:-laf

:-laf

 

[FJfonda]

MPG Mods

All my driving is in the northeast, lottsa hills.



Unloaded - On open highway at 70-75 mpg I normally get 13 mpg. My mpg "mods" are new FCA, cool hose, airbox snorkle mod, free flow muffler, valve adjustment to nominal and Smarty Jr set on 40hp. On a recent trip, 400+ miles each way, logged 15 mpg at 72 mph one way and 14mpg at 78mph on the return trip.



Towing - At 65-70mph towing open highway pulling 12K boat/trailer I normally get 8mpg. I have not towed any distance since the mods.



The Smarty Jr changes the throttle response so much, I'm sure I am wasting mpg's just to feel the additional response.



On this truck, I have not even come close to the MPG's others have posted..... my '99 I came pretty close.

 

[steved]

A RokkTech sensor, swiss-cheesed airbox, manual hubs, and very conservative driving... the best I've did (repeatable) to date is 23mpg. I average 17-18 in 50/50 highway/heavy city traffic and around 20mpg highway. And that's with 4. 10 rears... 3. 73s will not see much difference (not as much as say a set of 3. 55s).

Ryan hit the nail on the head... these trucks do best at LOWER RPM... mine is best about 1800, starts sliding back around 2000, and is drinking like a fiend at 2200+. If you think you're going to get great mileage running 65+, your dreaming.

My optimum speed/RPM is 60mph... I get better running 50mph, but that's not really optimum.

The only thing I will add is that the airbox itself is not that restrictive, but the fresh air intake tube through the inner fender is restrictive... drilling my air box full of 1-inch holes made a significant improvement.

 

[AABEN]

USCMCBay DO NOT LET dodge flash your brane box Thay did mine and now i only get 22 at 50mph 18-19 is good for me now

 

[Grizzly]

I don't know why and I'm not willing to change anything - but I am getting 28. 5 to 30 mpg - "physically" not electronically. I went from Houston to Orange, TX at the border filled up there... went to Orlando, FL filled up - spent a week there - topped off before I left and made it back to Houston on two tanks.

I was coming back from Odessa, TX with a hard tail wind at the end of March and figured 31+ mpg.

I bought the truck over a year ago and put in an Edge EZ and nothing else. I run Injector cleaner through it pretty often but other than that - I have no idea what the previous owner did.

I am starting to get a white smoke - 175k miles so need to pull an injector and replace whats in it now.

Just the facts - no BS - no reason too...

Why am I having a hard time believing all this?



The best way to increase your fuel mileage is to lie about it. That's what my brother-in-law does about the high fuel mileage he gets with his Furd Super Duty Powerjoke.

 

[05mxdiesel]

I don't understand either.



Truck in sig with 70k, last tank averaged 19. 6 all highway (450 miles) with TST on 3/2 and a light foot. 65mph at 1750 rpms. This is with 4 adults and luggage. My running average since new is 16. 8 with towing and a lot of low mpg winter driving. A guy over on BITOG claims high twenties in Florida running 70-80mph with a quad module.

 

[TFucili]

Man, I'd be a happy camper if my '05 could get anywhere near that. I get 15-17 around town, and have never even broke into the twenties running empty. I will, admittedly, set the cruise to 70-75 on the highway, but drive very conservatively otherwise. I would love to see someone program out the third injection event to see how much, if any, improvement could be had.