And, I'll say it again: 2007 Federal Emissions Standards.

It's a fact of life, so will be higher engine costs, lower fuel mileage, and uh, much stricter rules on exhausts, Cat's, and programming changes. Get used to it.

 

comes out n new trim at a low rating so that every other year theycan tweak a few settings and increse the power with no new engineering. Its that simple, also gives them two free years to come up with a better tranny, to handle all that new found power. then its 2 years another hp bump, wait.... body style change on a mid year...... year later bump hp.......... endless loop to keep us on the edge of our seats and wanting a new / better truck.

 

But, as always, you can get around the emissions and unleash full power with a programmer.

Good luck getting all that power to the ground, however.



And it is somewhat ironic how people complain about reduced power after they say that it's what they'd prefer, anyhow...

 

Just posted this in the general diesel catagory. Just some opinion on the new 6.7:

Not sure if it's been discussed here before, since I'm somewhat of a new member, but one trend I keep seeing (especially since the new 6.7 intro) is that everyone keeps refering to horse power as the end all of truck engine ratings. I'm not ranting here but guys and gals please take a look at the following info. HP is just a function of Torque and really doesn't mean anything. Torque (given the right number of gears to select from) is what is important.

Torque is the moment of a force, acting at a distance (which tends to cause rotation).

Work, in a linear since, is the product of a force exerted on an object and the distance that object moves. With spinning objects (think input shaft here) work is defined as the product of torque causing a rotation and the angle through which the object turns.

Power is work done in a certain time unit.

So:

power=work/time or (torque*angular rotation)/time

Horsepower=(Torque*RPM)/5252 (this is why you see HP and Torque lines crossing at 5252RPM on dyno sheets, if you have an engine that revs that high)

The new 6.7 as I understand it is a 5.9 with a longer stroke. When going from shorter stroke to a longer stroke actual piston speed being dependent on a larger circumference crank rotation is higher (speed of the piston is faster at given points of crank rotation) which translates to the need for much higher rates of acceleration and de-acceleration at the end of the stroke for the piston travel. This is why (usually anyway) that engines that have been stroked have lower max RPM ratings and hince lower HP ratings for a given torque value.

Sure, I would have liked to see a higher torque rating for the new 6.7 but given that fact that the first intro for the new 6.7 is for commercial duty cab chasis trucks and the fact that these new trucks will have egr's, cat's and particle filters it's not that bad. Something else to keep in mind. I would bet that the torque curve for the 6.7 is much flatter and keeps a higher rating at extended RPM's than the 5.9 does. Just a guess but is usually the case for longer stroked engines.

Sorry for the long post.

 

Exactly what I was thinking.

 

emissions everybody in the diesel world isn't going to like the numbers they see on new motors. Almost none of the curent engines being build are going to pass the new standards

 

Thats horrible...my truck is going to be in for it then....Oh well looks like I'll be forced into getting a new exhaust and such....Just take off the chip I guess when I go through emissons so who knows!...now I just notice my tags are expired

 

No, chaos - you're fine! It's the BUILD DATE of the vechile that matters. All previous trucks and older "emissions control" systems will be grandfathered on so that you will still not have to be tested. Note: This may not be the case everywhere, if you're in California, you may already need to be tested, you'll have to check you local regulations.

But if you want a new truck, the '06's are looking better and better, aren't they...

 

There are other threads on here and other posts that point out that the release has a few errors in it.
Even the dealers know that the 6.7 will be a higher powered Cummins then what is out there now.
Specs they posted in that press release had mistakes.

 

My guess is also that this is designed to be a work truck driven by people who flog the crap out of it.

This is not the same thing as your consumer 3500. In fact supposedly 07 non-Chassis Cab 3500 is still getting the 5.9. BTW This engine makes 350 HP and 750 LB FT in other applications. So the engine is capable.

For me I am very happy with this truck - not at all disappointed. This is basically a Dodge/Cummins haulers/hot shotters dream.

 

I've read that the is the non h/o rating and the H/O will be coming out at a later date

 

If the 2500 and 3500's keep getting the 5.9, does that mean that it already meets the 2007 epa regs? Or is DC just doing this to keep selling 06's then announce that the 6.7 will be in the complete line up?

 

Maybe I'm just dense, but I don't see the connection between tank SIZE and FUEL BILL.

The only think tank size affects is fueling FREUQUENCY, right?

 

Well, the added weight of the extra fuel would reduce fuel efficiency, which means that you would be paying more for the added size of the tank.

Like an airplane, or a rocket.

 

Quote:

Originally Posted by RC51

Just posted this in the general diesel catagory. Just some opinion on the new 6.7:

While you are correct, you're drawing the wrong conclusions.



You say that HP is a function of torque. Another guy might say that TQ is a function of HP. Who's right? The answer is that it's all relative.



The proper answer is that HP is a function of TORQUE AND TIME!!! That second component (time) is HUGELY critical, because it allows us to use gears to trade one for the other. In other words, I can always trade time (the RATE of work accomplishment) for Torque (the amount of work you can do). or vice versa.



Gearing can multiply torque, but will divide the time to do so. Common sense tells you this is true. If you have a 5:1 gear reduction, you get 5 times more tq output, but the shaft spins at 1/5 speed (or RATE)--you lose one for the other in a linear relationship.



When you realize that hp is a function of tq AND time, you see that HP IS WHAT MATTERS, NOT TQ. After all, if you need more tq, you can always use gear reduction.





Power across a gearset will always be constant. Tq will NOT.





People who think that "TQ is king" for towing and such really don't understand the concepts of tq and power.





Say you have a 325hp CTD (with superior low-rpm grunt) and a 325hp Gasser (that has to rev to make power) hitched to identical loads pulling them up a long mountain grade. Further suppose they have fictional ideal transmissions that allow them to operate at peak HP rpm.



The two trucks will pull the two trailers up the same grade at the exact same maximum speed. Why? Because the have the same power. The fact that each has an idealized transmission allows them to also create IDENTICAL tq to the wheels, and pull their loads at the same speed. Remember, power is the rate of work accomplishment—how fast (maximum speed) you can pull the trailer up the hill. The work is the load—how much trailer and how steep a hill.



So if power is all that matters, then why is the “torquey” Cummins so famous for towing performance? Simply put, because there is no such thing as an ideal transmission. In other words, tq/power rise (how fast the tq output of the engine rises relative to RPM) and powerband linearity are EVERYTHING.



Consider the typical towing scenario of trying to accelerate away from an intersection with a heavy load. How would this scenario play out with a typical gas engine versus a Cummins Diesel, side by side?



Both vehicles are equipped (let’s just say for now) with an NV5600 tranny. Diesel truck pops the clutch and launches in 1st with little fanfare because the Cummins has over 400-lb ft at idle (800 rpm). Gasser truck has to feather the clutch because he’s only got 250lb-ft at idle (800rpm).



The Diesel truck’s tq output rapidly rises to 600lb-ft just off idle (1400 rpm) and levels off as he revs out 1st gear to 2000 rpm or so. Diesel shifts to second gear at 9 mph.



Meanwhile, gasser has been accelerating more slowly because his engine has to rev to make more power (remember tq rise?). But he doesn’t need to shift nearly as soon, so he’s still in 1st gear long after Diesel has had to shift to Second.



Now, 1st gear on the 5600 tranny is 5.63:1 while Second gear is 3.38. When Diesel shifted to Second, he lost 40% of his tq output at the wheels! So Gasser is winding up to 4000 and doesn’t shift into Second until after 18mph.



But Diesel didn’t stop to wait for him. He’s since shifted into 3rd gear, a 2.04 ratio, at 18mph. This costs him ANOTHER 40% drop in tq to the wheels.



So let’s compare power to the ground at 18mph:

Diesel is in 3rd gear @ 1400rpm. 600lb-ft * 2.04= 1224lb-ft

Gasser is in 1st gear @ 4000rpm 365lb-ft * 5.63= 2054.95lb-ft



Now, to be fair, Gasser is about to shift and Diesel has already shifted. If Diesel had stayed in 2nd gear, he’d have 600*3.38= 2028lb-ft output.



Interesting. The Gasser at 4000rpm in First (high gasser rpm) has MORE towing power than the Diesel does at 2400rpm in 2nd (high diesel RPM) and MUCH MORE than Diesel has at 1400rpm in 3rd. In all cases, speed is at 18mph.



As we get up to speed, eventually both will shift into 6th at 70mph. At 70mph, Diesel is turning 2000rpm and putting out 600lb-ft into 6th gear (.73). He has 438lb-ft to tow with. Gasser is also in 6th at a steady cruise, 2000rpm but only putting out 280lb-ft. He has a measly 204.4 lb-ft of towing oomph at steady cruise, and might not have enough to even maintain speed.



But Gasser could also run 5th gear at 2750rpm instead. His engine would make more torque at this higher rpm (he’s up closer to 315lb-ft now) and would run in direct. So he’s up to 315 lb-ft to tow with. Diesel could ALSO run in 5th turning 2700rpm, but he’s no as comfortable doing so. Here he’d have his full 600lb-ft to tow with.



Furthermore, Gasser could downshift AGAIN to 4th gear and rev to 4000 rpm. This would take his engine to its peak tq output of 375lb-ft and give him (via 1.39 gearing) 521.25lb-ft to tow with. This is superior to Diesel’s overdrive cruise, but not his downshifted performance.

All this to make the longwinded case that it’s POWER is the ultimate determinant of towing performance, and more importantly, how accessible that power is. I’m also trying to show that even though POWER is king, TORQUE still matters because it determines WHERE in the engine’s RPM range you will have the POWER.



The CTD puts its power out right off idle, and makes the power VERY accessible, which equates to a more enjoyable towing experience.