more on our duramax... empty

[_MACKIN]

I'm sure the prices will come down. Gotcha by the B**L'S right now... ... ... When the D-MAX first hit the streets the stealers were fetching a whopping $143 bucks for a fuel filter now there down to $60 I think. . Now you can get them from D. I. S. for $17 bucks and change, each, for a case of 5... ... Same dam filter... ... ..... Oil filter $16 bucks for a AC @ stealer... . Down to $10 bucks now... ... . You can by hastings or others cheaper. . I stick with the AC... ... . They'll have some after market injectors soon... . I think that there may be some out already... ..... GM only has a 5yr 100,000 warranty on there power train excluded is the Allison ,which is 3yr 36,000 ,which IMHO sucks... ... . Dodge is 7yr 70,000? Or is it more with the Cummins?

MAC

 

[Champane Flight]

Na

Its 100,000 on the Cummins, however hear that they are going to 150,000 next year. Standard drivetrain was 5 and 36,000, I think they went 7 and 100,000 this year.

 

[Ray Torresdal]

milage

Packman,



I still haven't seen comparisons on fuel milage. How do the 3 compare, loaded, empty, average??? Anyone else out there with good information?



Thanks!



Ray

 

[HoleshotHolset]

I highly doubt that the DuraWhatEVER!! or the PSD will use less fuel than the 12-valve Cummins 6BT.



The 12-valve has a lower BSFC (Brake Specific Fuel Consumption) constant which means it burns less fuel... ... the ISB is only slightly higher with its BSFC constant.



The "other two" engines are larger in displacement, so more cubes = more fuel. You have to maintain the same air:fuel ratio in every cylinder (or at least approximate it... . )... . so if you have two more cylinders... . you know the rest.....



Matt

 

[rob10858]

fuel mileage

still can't get my driver to set the odometer and make a mileage test. we've seen the powerstrokes come in at 7 loaded and 13 empty. pitiful, its like the boss said, no better than our v8 and v10 trucks. of course they have are 550's and geared much lower [or higher depending on how you look at it] some ford guys may boast twice that figure, but a v8 is a v8 gas or diesel. the ctd will always outperform the competition in this category.

 

[Mark_Kendrick]

Originally posted by HoleshotHolset

I highly doubt that the DuraWhatEVER!! or the PSD will use less fuel than the 12-valve Cummins 6BT.

I agree... but...

Originally posted by HoleshotHolset

The "other two" engines are larger in displacement, so more cubes = more fuel. You have to maintain the same air:fuel ratio in every cylinder (or at least approximate it... . )... . so if you have two more cylinders... . you know the rest.....

Diesels do not have a set air/fuel ratio. Diesels are metered by fuel alone. Air is supplied to keep the temps from soaring... or more like the fuel is metered to make use of the air available but engin speed is determined by the presence of fuel.



Gassers have a 'fixed" fuel to air ratio. if they run lean they have egts similar in temperature to a blow torch. rich they foul plugs and run poorly. Gassers meter the air and supply fuel to match the intake.



You'll notice that diesels don't have Mass Air Flow sensors.



My dad has a PSD that gets very good mileage. It won't last as long or out pull my 'less powerful' CTD but it gets better mileage.



Larger in a diesel does not necessarily mean less economy.

 

[MABurns]

My 94 and 99 CTDs both had an AT and 3. 55s. I got about 18-19 empty and 12-13 towing in them.



With the Duramax/Allison combo (3. 73) the best average tank I have ever had is 20 empty. But average about 18. Towing has been limited (got the truck in OCT) but the few short trips I took where about 12 mpg towing.



I really think the D/A is more MPG-speed sensitve when empty than the Dodges. I mean the Dodge tended to get about the same MPG between 60 and 70. Dropped off after that. The Duramax will crack 20 if you keep it at 60 or below, but drops to about 17-18 at above 70 mph. (and 15-16 with cruise set on 80).



My problem is I just can't keep from rompin on it. The D/A combo is much quicker than the stock CTD and auto.

 

[PRout]

Its amazing how Isuzu owners love to campare the quickness of their higher reving diesel to the "stock" cummins.



If they cant beat one of those, they must be hurtin' pretty bad because we all know the stock detuned cummins is a TOTAL SLUG!



We knew that when we bought em.



Thank goodness our little cummins motors are "Plug and... Play"



Why do we plug in goodies, & throw in giant injectors just to be able to go out & totally blow away aluminum Isuzus & Powdercroaks???



Cause we can...

 

[LarryB]

Remember, the little 12valve runs stock 370hp in the Diamond B version. I guess that would make the truck version running just a little over half throttle. And it still gives them "World Killer V8s" a run for their money. LOL, :-laf :-laf :-laf

 

[PRout]

Larry,



Were we supposed to shift out 1st gear??



Ok, ok, I know. We should show some restraint & be fair to the guys that come around trying to stir up the pot.

But sometimes its just too much of a laugh to let go by without some hint of rebuttal.

 

[Champane Flight]

95

My 95 never drops under 21 empty and has a high of 25mpg. A low of 12 pulling fithwheel and boat with a headwind, but average around 14-16 loaded. This is with a standard and 3:55s. My average empty is 22. 5 .

 

[Gary - K7GLD]

I ocassionally see reference to some of the higher power versions of the 5. 9 engine - yet when major power swaps or upgrades are done, it's always going to an 8. 3 - or LOTS of $$$ beefing up the B5. 9... Why hasn't someone just gone to one of the other versions of what we already have? Is there a difference in physical construction?

 

[HoleshotHolset]

BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC



yeah, I know diesels have no set air:fuel ratio... that's a given.



Gassers don't have a set air:fuel ratio either... . they just happen to have one stoiciometric (sp?) ratio (14. 7:1) that happens to allow them to have the best efficiency... . notice I didn't say power.



In a way turbo-diesels are speed-density... . they vary the fuel based on the presence of manifold pressure.



But to make power the fuel:air ratio increases numerically.



Having two more cylinders to feed... will lead to more fuel consumption.



So, a 4BT uses less fuel than a 6BT... plain and simple... . irregardless of what air:fuel ratio either of them are operating at.



Gee, I better go out and get that Cummins Signature 600..... it won't use any more fuel than my 6BT... . yeah right.



BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC BSFC



Matt - look for the subtle hints of why one engine uses less fuel than another.

 

[HoleshotHolset]

Gary,



The C8. 3L (or 6CT) is a totally different beast..... basically a beefier version of the 6BT... . it's 800# heavier, but makes more HP right out of the box.



Pulling guys could use this one... . but the nearly 1 second ET handicap makes it tough for the drag racing crowd to handle.



The 6CT is about 4 inches longer..... same width and same height... . (in general terms).



Matt

 

[Gary - K7GLD]

Matt - this post of LarryB's is what I was referring to:



"Remember, the little 12valve runs stock 370hp in the Diamond B version. I guess that would make the truck version running just a little over half throttle. And it still gives them "World Killer V8s" a run for their money. LOL,"



SO, if the "Diamond B version" (assuming it is a higher powered version of our B5. 9) - why hasn't anyone swapped one into a Dodge, rather than spending lotsa $$$ beefing up the stock B5. 9. and then watching for broken parts and blown headgaskets?



Be gentle - I'm not very well versed on different versions of Cummins engines, other than those used in the Dodges... .

 

[HoleshotHolset]

The 370-Diamond B marine engines are not very well suited for automotive use... . although they are very beefy and well balanced.



Especially if you happen to buy a reverse rotation engine... . man, it would go like heck in reverse... but nowhere in drive!! Not to mention... . you would be cranking the engine in the wrong direction with your OEM starter/location and you'd probably be hard pressed to even get it going if you thought it was the proper on-highway rotation... .



Bear in mind... . a marine engine is setup to run at whatever cruising speed a boat uses... ... measure it in knots, NMPH, MPH. . whatever... . Seeing as this engine is setup to run flat out all day long... . it is not designed to nicely accelerate or run very well (or as well as an on-highway application... ) at part throttle... . or anything less than governed rpm.



This is why folks don't (usually) put a 370hp pump in their on-highway trucks... . they're just not setup for road use.

I thought I read somewhere that the 370hp versions had a different AFC housing... . and this is where the bulk of the problems lay.



Not to say that it couldn't be done... . it has been done... . and it has worked well..... example: 12-valve in the Dakota guy, etc... .

There are some issues to work out... . but it can be done!



Besides, you'd have to get rid of that pesky aftercooler so that you could run a regular old air/air intercooler! :-laf



Matt

 

[ABailey]

Originally posted by cditrani





quote:

--------------------------------------------------------------------------------

Originally posted by Shawn. L. Turbo



Wrong. Torque acclerates you. ... snip...



Shawn

--------------------------------------------------------------------------------



I respectfully disagree. hp is calculated from torque and rpm because that is the only practical way to measure it with a dyno. hp is a measure of how much work is being done. It's work that accelerates you.



Put a wrench on stuck bolt. Apply 10 #' of torque. It's till stuck, so it doesn't move. You are applying 10 #' of torque, but you aren't accelerating anything. You aren't doing any work.



... snip...

cditrani:



You may disagree but physics is physics and so far Newton's laws of motion still hold in this universe. :{



Newton's 2nd law: Force = mass * acceleration (F = m * a)



Torque is simply rotational force.



Work is force * distance (W = F *d) and Power is work / time (P = W/t)



So power is simply force * velocity:



P = W/t = (F * d)/t = F * v where v = velocity.



Without force and hence acceleration, you have no power.



Here is a nice conversion: 1 hp = 550 ft * lbs /s (or 746 W for the SI folks)



Your bolt/wrench anology is flawed. Your wrench doesn't move because the frictional force holding the bolt is greater than the torque you supply. If you supply enough torque to exceed this frictional force, guess what happens? Your wrench will accelerate and hence begin to move.

 

[PRout]

Power is power. You have enough or you dont.



Just came back from vegas pulling the trailer. Had my first Dmax encounter (sort of).



Coming up halloran pass (lonnnng steady grade through the desert) I was at about 18k gross and rolled past a dmax pulling about the same size trailer. He was in the right lane cruisin w/ the trucks at about 50mph. I was keeping up w/ the cars and rolled by at about 65 but not pushing it. was holding 1175* and about 185* on the water temp. I figured he decided to play the pulling game, because I could see the concern in his eye when i rolled past and knew he was gonna be coming.



Sure enough he made a pass on the trucks and was about 3 cars behind me. I rolled on a little more juice to make him work for it. Kept the temps at 1200/190 figuring that gives me a good safety margin, but thinking that 1300 was available for a short burst if necessary.



Well, I sorta just kept increasing the gap which was a little surprising because I thought he would be coming. Especially with what the guys have been saying about this SUPERIOR machine. After I crested the top, I figured that he wasnt intrested, and was thinking it was a "false alarm".



Next thing I know... here he comes... rolling by with authority (on the downhill ) I was on the ebrake and he was haulin' tail. The lady passenger gave me the smirk as they rolled past. Well 68 on the downhill was more than I like, so let the moron go.



Anyways, I ended up rolling past him on the next grade. Kept 1200* as I rolled past him at about 70. He just couldnt do it on the grades, and made a try but thats all it was (didnt need to take it to 1300 after all).



Sure enough they flew past me on the next downhill with a smile, cut in in front of me w/ a nice aggressive lane change closing the door on me... then proceeded to pull off at the next offramp, probably for a hamburger.



Was funny how Id pass him on every grade and he'd roll by on the downhills. . My little 'ol cummins is very mild w/ DD1's & a VA (how it should come stock from the factory IMO). No extra fueling whatsoever.



You can have your dmax.

 

[DHess]

Stock or BOMBed, the Cummins is in it for the long haul up and over the top. The two extra cylinders and more cubic inches in a V shape are nice for moving quick off a stop light and cruising down the highway. For putting the muscle to the road and getting the tough job done, in style, the Cummins shines.



Dave

 

[Gary - K7GLD]

YEAH - and the funny part is, That guy - or one just like him - will be bragging over in the GM group about "beating a Dodge" - but will leave out the downhill part... And CERTAINLY won't mention the UPHILL bit...



And all the REST of the rail birds in the group will be whistling, cheering and clapping each other on the back about Duramax "superiority"...