325/600 fuel economy?

[TCrawley]

I have 5600kms and I am getting over 825km per 110l of fuel. Hand calc. at around 18. 5mpg (unloaded). I love my truck but do wish mine was a 555/305. I will be getting a Edge box soon.

 

[CoastyAV8R]

I don't understand why you would want a 305 when your getting good mileage and had nothing bad to say about the truck?



I'm happy with my 600 as with 6700 miles on it, I get almost 18 mpg in daily driving and 10-11 towing the loaded down toyhauler. It is a much faster/stronger truck than my previous 01 HO Dodge, much better brakes and overall is more refined. I'm amazed at the fact that there are trucks out there getting bad mileage and poor power, you would think in this day and age, it wouldn't happen. I wish that everyone who bought a 600 were as happy with their truck as I am with mine. I would be a little upset if I had gotten a dog, but this being my third Cummins, it is far and away the best one yet.

 

[MartinBlair]

2004 calif. 235 hp (EZ)

I to have an early 04 low output engine. (calif 235 hp)

Added the EZ chip, and Wow.

Mileage is up and it feels like HP & Torque doubled.

I went to the local dealership and drove a 300/600.

My truck will run circles around it. I was surprized. .

According to the overhead, At 70 miles per hour it maintains 26 MPG.

Don't want to rain on anyones parade with the 300/600. I have to believe

there is something in that control module that adds extra useless fuel timing event

that was excecuted for emmission control only. . this would explain the mpg outage and some sluggishness. . I have to believe that the addition of a pressure/timing module would cure the 300/600 blues. .



By the way, my truck is an early 04 calif 235 hp. 2-wheel posi, 3:73 rear. . 2500... And no, the weight difference between a 2500 2 wheel and 2500 4 wheel drive is not enough to make significant milaege differences.

 

[DPelletier]

Some observations, since I have one of each;



- I would agree that overall we should accept that more power = less mileage. That having been said, the 555 produces only slightly less rwhp. Although I haven't done a strictly scientific comparison, my 555 gets a high (ideal conditions, 60mph, highway, empty) of 20. 2 mpg. The 600 gets 2 or 3 mpg less, but it does have a little more power. I'm happy with both and when I go to buy a 3rd one, I could go either way.



- The widely varying mpg reports are expected. Different trucks; ie. 4wd vs. 2wd; drw vs. srw; lwb vs. swb; 6spd vs. 48RE as well as widely differing driving habits; speed; hills; wind; load; tire pressure; temperature; elevation all conspire to make real world mpg comparisons difficult in the extreme. So much so, that alot of the information on mpg in these forums is borderline useless IMO. I firmly believe that the changes made to the motor in the 600 (primarily the 3rd injection event) cost us 1-3 mpg all things being equal. Some of the people getting really bad mileage have an actual problem (most likely injectors IMO) and some really bad mileage reports have more to do with the other things I've mentioned (as well as some of the really good reports!)



- I get sick of hearing about "my new 600 is a dog compared to my '01 with injectors, fueling box, etc. etc. " Well duh! Totally unfair and irrelevant comparison to compare a modified truck with a stock one. (This comment isn't directed any anybody in particular, by the way. and I didn't mean your comment Barry). Anything other than a 555 simply doesn't have anywhere near the power of a 600, stock for stock.



- Gary, go back to the "last of the real Cummins powered trucks" forum (known to the rest of us as the 2nd gen forum) where you belong! There you can sit all day and talk about how wise you were for buying a 2002 truck whilst sipping bottled water! Just kidding!



Cheers,

Dave

 

[opjohnny]

It's not the weight as much as the frontal area that makes the mileage difference on the 4x2 vs 4x4, when you start trying to push 75mph or better. I believe these trucks don't get broke in till over 30k unless pulling full time.

 

[favord]

Up to 12K on mine, over 10K towing horse trailer. Still get 8-9 mpg at avg speed of 70mph. I don't drive unhooked enough to really know mileage but the computer is usually around 12-13 empty. The power is OK but nowhere near a mildly bombed rig IMO. If I were to do it over, I'd buy a used and much cheaper 01-02, put on a few simple mods, and really get down the road with likely better mileage. I used to run up the hills in the left lane and now I'm chugging along in the right lane with the big rigs getting blasted by old Dodges, new F's and C's. I think the 04. 5 is a bust... or at least surely doesn't live up to its hype.



On the plus side, it does get me where I want to go, I can hear the radio and talk on the phone easier. The ride (prior to air bags) was nicer and probably nice for taking the missus out to dinner. Looks cool. Good city rig.

 

[BrentKaiser]

Some observations, since I have one of each;



- The widely varying mpg reports are expected. Different trucks; ie. 4wd vs. 2wd; drw vs. srw; lwb vs. swb; 6spd vs. 48RE as well as widely differing driving habits; speed; hills; wind; load; tire pressure; temperature; elevation all conspire to make real world mpg comparisons difficult in the extreme.

I agree completely. I also think that how you "try" to break your vehicle in, changes the equation even more. I have 550 miles on my truck and have been getting 11. 5-12 mpg. Owners manual instructs to hit it with a load after 500 miles. I can only imagine that a few thousand miles of some heavy towing will get this baby working and increase my mpg.

 

[Barry]

If the "600" is a cleaner engine, why was my right rear fender black all the time? The other thing that was explained to me was the post injection that shot in the cyl. , after the piston fired, to keep the egt hot so the cat conv. could do it's job. From a force standpoint, it has not benefit other than emmisions... ... ... . I loved the truck, did not like the 600... ... ..... POW, it's HISTORY!

 

[RustyJC]

Barry,



Wanna buy a REAL truck??? See signature.



Rusty

 

[DPelletier]

Why Rusty, are ya lookin' at a new one!



Resistance is Futile.



Dave

 

[RustyJC]

Why Rusty, are ya lookin' at a new one!

Dave,



If I were, it would probably be a Peterbilt 330! :{ :{



Rusty

 

[rashwor]

Trading Rusty? Just being nosey. I thought you were very happy with your '02.

 

[RustyJC]

Trading Rusty?

Not unless I hit the lottery. I love my '02 - I'm just a little, ummm, overweight! :{ :{



I'm really just raggin' Barry about his move over to the "girlie diesel" side.



Rusty

 

[DGStrate]

Cummins 600 - performance at cost of fuel!

Hi everyone!

Like Scott, I must have the mystical Cummins motor, but I can GET decent economy out of it, it just takes a little work.



Now, with 5k on the odometer, I repeatedly can achieve 20. 7 to 20. 9 mpg (empty of course) if I set the cruise at 71mph on the freeway and LEAVE IT ALONE. I have a LWB 4x4, 3. 73 gears, bfg 315s, QC, 48-RE graphite beast! It is the passing and city driving that KILLS mileage on my particular truck. Speed over 71 does not help either. Please note that these are hand calc'd numbers and that the 71mph is set using a GPS (as I do not have my speedo corrected currently).



So the long and short? I can take it easy and get great mpg or I can have fun passing other rigs and cars, but the economy suffers substantially. Truck is BONE stock other than the tires.



The 4:10s would have helped GREATLY around town, but I did not want to suffer the rpm penalty at speed (I like to drive fast), and I do not tow heavy enough to require that ratio.



As has been mentioned, I think 2 issues are at hand:

1) the motors do not seem to be consistent as far as performance,

and

2) How you drive makes a HUGE difference.



Cheers to all! I love the TDR and my Cummins!

-Derek

 

[JPalese]

Hi everyone!

Like Scott, I must have the mystical Cummins motor, but I can GET decent economy out of it, it just takes a little work.



Now, with 5k on the odometer, I repeatedly can achieve 20. 7 to 20. 9 mpg (empty of course) if I set the cruise at 71mph on the freeway and LEAVE IT ALONE. I have a LWB 4x4, 3. 73 gears, bfg 315s, QC, 48-RE graphite beast! It is the passing and city driving that KILLS mileage on my particular truck. Speed over 71 does not help either. Please note that these are hand calc'd numbers and that the 71mph is set using a GPS (as I do not have my speedo corrected currently).



So the long and short? I can take it easy and get great mpg or I can have fun passing other rigs and cars, but the economy suffers substantially. Truck is BONE stock other than the tires.



The 4:10s would have helped GREATLY around town, but I did not want to suffer the rpm penalty at speed (I like to drive fast), and I do not tow heavy enough to require that ratio.



As has been mentioned, I think 2 issues are at hand:

1) the motors do not seem to be consistent as far as performance,

and

2) How you drive makes a HUGE difference.



Cheers to all! I love the TDR and my Cummins!

-Derek

Derek, will you give me driving lessons?



With the exception of a short box and stock tires, I have the identical truck. The BEST hand calculated mileage I have EVER gotten was 16. 9. {If I drive over 65 the mileage PLUMMETS. }



I drive conservatively... if my wife gets in it, the mileage drops 2mpg as she has a big FOOT.



How can there be such a big mileage difference? What am I doing wrong? Whats wrong with my truck?

 

[HParfitt]

I think the difference we are all seeing is due to the brand of oil each truck is using and if it's synthetic or dino! :-laf :-laf

Also the type of muffler bearing grease. Synthetic or non synthetic

Oo. Oo.

 

[KevinO]

I must have some mystical 600 then... just because you got one that gets crappy mileage, no need to hate on those that get decent mileage.

I'm not hating i just don't see how these trucks can vary that much since the motors have been such high quality since cummins has been put into these trucks. I had an 01 with mods that would yes smoke this new truck stock, but it still got better mileage. I guess "cleaner" emissions are better than saving 4-5 mpg. Just can't see how that is though.

 

[Gary - K7GLD]

"I'm really just raggin' Barry about his move over to the "girlie diesel" side. "







One very nice feature on the newer trucks, is the absolutely AWESOME gains in power they make with the power boxes...

 

[DGStrate]

Derek, will you give me driving lessons?



With the exception of a short box and stock tires, I have the identical truck. The BEST hand calculated mileage I have EVER gotten was 16. 9. {If I drive over 65 the mileage PLUMMETS. }



I drive conservatively... if my wife gets in it, the mileage drops 2mpg as she has a big FOOT.



How can there be such a big mileage difference? What am I doing wrong? Whats wrong with my truck?

JPalese,

Here are the secrets and suggestions that I have:

1) accelerate like a grandma to get ON the freeway

2) make sure that you set the cruise and have open road

3) resist the urge to "blow by" those rice rockets with full turbo whine authority



How many miles do you have on the truck?

Any hard driving or towing? I noticed a HUGE difference in mine after working it REAL hard a few times (get the cylinder temps up nicely - helps seat rings/etc. )



If you are STILL getting bad mileage, start checking things...

1) Air filter - not restricted?

2) Change fuel filters

3) Change where you buy your fuel - I have noticed up to a 1-2 mpg difference between stations

4) Make sure you are "filling up" consistently (same amount/cutoff point each time) AND at the same pump for good comparisons

5) AIR UP the tires . . . esp. if you have stockers - put 'em at 70-80psi

(I was running my BFGs at max pressure)



The other thing I can think of is that with stock tires, you are turning more RPMs than I, so you may plummet your mileage above 65, whereas mine does not drop off until 70-72 due to the simple reduction in gear ratio caused by the 34. 6" tall BFGs versus your 31. X stock tires.



Best of luck... if you want to PM me your #, we can talk more and compare further via phone...



-Derek

 

[thames1948]

with my 600, empty, with my foot in it, I get about 16 city and about 20 hwy. Not sure on towing yet. . havent had the chance to tow. 4x4, 6 spd 3. 73's.

Scott

16 in city with your foot in it. All I can say is WOW! You are the lucky one.