waldersha

Hey guys, does anyone know where I might be able to lay my hands on a curve for the Cummins (any generation) and the HEMI? I am trying to explain to a non-car guy the difference between dyno HP (and torque) and the real-world.

He keeps trying to tell me that the HEMI is a way more powerful engine based on their HP numbers. Can't talk him in to a pull though.

Timmay2

Edge products will have dyno charts for a wide year of trucks and products:

http://www.edgeproducts.com/dodge.html

Hannibal

The Cummins makes it's horsepower at a much more reasonable rpm. It makes over 200hp at 2,000rpm where the Hemi needs to be at 3k rpm to make 200hp. The Cummins makes 325hp at 2900rpm while the Hemi needs to be at almost 5k rpm to make 325hp. Through gear reduction, equal horsepower will equate to equal torque output at the driveshaft. Just depends on how you feel about higher rpm and higher fuel consumption with the Hemi. Also it's shorter life if you add 'em up quick.
My '05 Hemi powered 2500 is a duplicate of my '03 Cummins powered Ram but for the engines and automatic trannies. Towing the same 5th wheel 65-70mph, the Cummins did the job at 2100rpm in O/D and 2900rpm on the steep hills in direct. The Hemi maintains speed just as well but it's at 2800rpm in direct and 4200rpm+ on the steep hills. Won't hurt the engine at all but it gets thirsty. Most folks cringe at the sound and don't enjoy the trip.
I went with the Hemi this time partly out of curiosity and partly out of fear of the dreaded driveline vibe I had in my '03 Cummins Ram being repeated in the '05. I'll likely be in another Cummins Ram one day but it won't be because the Hemi is lacking for power. It's just at a higher rpm. Not to be misunderstood, the medium duty Cummins 5.9 is the best engine ever put in a pickup truck. For what it is, I believe the Hemi is the best small block V8 ever put in a pickup truck for power, relative fuel efficiency and reliability. Time will tell. If it croaks I'll have to eat those words.

Hannibal

Almost forgot. The dyno is great for bragging rights but a short measure of HP on an acceleration of about six seconds says nothing about real world towing. Hook up some weight and hit the hills. A 6% grade with 10k lbs behind will seperate fact from fiction.
Here's the advertised HP/Torque curves for the Hemi. The Cummins is easy. 610 ftlbs from 1600-2900rpm. Pick your rpm, X 610 / 5252 = HP.

Lil Dog

DodgeRam.org has a couple in its diesel section.

Here is a 24V plot from 2001

And from 2002

waldersha

Thanks for all the replies. Great stuff!

RustyJC

Just to illustrate the difference between a gasser and diesel, my dyno results are in my signature. What's not there is the fact that my truck made 300 or more RWHP from 2200 to 3200 RPM - almost 2/3rds of its working powerband of 1600-3200 RPM. Compare that to the narrow peak BHP of the Hemi and the revs necessary to obtain it.

Of course, mine is set up strictly as a towing rig.

Rusty