We have been hearing rumors for a while now that the 5.9L CTD will soon be replaced by a new 6.7L engine. The link below provides the best evidence that I have seen so far to support this. Cummins themselves say that "The ISB engine has an increased displacement for 2007, going from 5.9 to 6.7 liters in size". New emissions regulations seem to be pushing the diesel manufactures to increase displacement, probably to make up for the engines being choked up by emmisions equipment. Ford is going to 6.4L and twin turbos, Dodge to 6.7, and GM is already at 6.6. It will be interesting to see if the new engines can hold their current ratings, or actually increase in power. We all remember the 70's when power took a big dive due to regulations. Maybe the technology is in place now to keep that from happening with diesels. I have heard rumors that the new 6.7 will initially be rated at 375/700. If this is true, then cummins has a winner. This could be why Toyota has reportedly been looking at Cummins for their future HD trucks. Has anyone heard ratings for the new 6.4, and does the current Duramax meet upcoming emmisions?

http://www.everytime.cummins.com/every/pdf/4103902.pdf

 

the dmax meets the ratings until 2010. i doubt toyota will use cummins. they have hino.

 

If that is true, Ford and GM will really have to step up to the plate. That's a lot of torque! GM and Ford will keep losing customers if they can't give them what they want which is MORE POWER!

 

The 375/700 number is just a rumor right now. However, since the current 5.9 makes 325/610, 375/700 out of a basically more advanced larger version isn't too far fetched.

 

Not far stretched at all. Infact, I'd be willing to bet the output numbers will be even higher than that. The 6.4L is still smaller than a 6.7 CTD....but the 6.4 has twin turbos, so, anything is possile at this point. I'm still hoping for 400 hp, and anywhere from 700-750 ft/lbs torque from the PSD. I'd love it. It really seems the new PSD will be the best for driveability due to the twin turbos.

 

If they are gonna put that much power in the Rams ,then they really need to put a new trans in it because that would rip the current auto trans apart.

 

If that engine is going in...there will probably be a 6-speed option.

 

Wow. Those numbers are really impressive. The thing I wonder is, when will it come to a head. If the manufacturers keep pushing the limits as far as size, power, and capabilities we will soon be driving medium duty trucks. Not that there's anything wrong with seeing what is possible, but the N/A 7.3L in my dad's F-450 will pull anything I want to hook to and not break a sweat. And it only has 185 HP and 385 lb/ft of torque! Just my thoughts.

 

With twin turbos, the new PSD probably will have very good driveability. Depending on how it is set up, a smaller turbo can provide excellent low end response with very little lag, and a larger turbo can take over at higher rpms for maximum power. I'm sure that there are some downsides to a twin turbo setup compared to well tuned single turbo setups, but if properly engineered the benefits should outweight any negatives. I can't wait to see how these different approaches compare.

 

Simple, the engine that can put out the most power AND get the best fuel mileage, wins.

 

Exactly. I believe this set-up will provide the best fuel milage from any of the manufacturers. My opinion...but the twin turbos are extremely efficient, and with the proper tune, I'm willing to bet we will start seeing full size trucks in the mid twenties in the next few years. That is, if the new emissions crap doesn't affect the engine as much as we think it will.

 

I think all these diesels will be seeing twins.

The power in the 70s took a small dive in hp due to emissions. A large dive in hp due to the way hp is calculated. 360hp in 71 was 230 in 72. Just the way hp was measured.

 

I dont know if the Duramax meets the emmisions standard but it wont take Isuzu long to fix that problem for GM. In Japan Isuzu has already made engines for commercial trucks that meet more stringent standards (though the US stuff might be diferent). And all the Ford and Mazda commercial trucks over there are actually running Isuzus becouse they couldnt meet the smog regs.
As far as Toyota going whith Cummins, this would be cool but i hope not. Toy diesels are probly some of the most durable engines on the face of the planet(i would rank them whith Isuzus and Benzos). Only reason i would see them going for Cummins is becouse in out stupid mind set over here if it dosnt have realy high HP and TQ numbers its junk which is vary unfortunate...

 

They actually run Mazda diesels...

 

I’ve heard in a few years when the emission regulations get even more stringent Ford is going to increase the displacement on the PSD again. I think I heard it was going up to 7.3L ha ha.