Folks, what is the powerband of the 7.3 as far as RPM's go? Thanks

 

seems to be right around 2,000 RPM. At least that is what gets me up a good steep hill with OD turned off.

 

About the first 25% of throttle and the first 1700 RPM's she runs like a dog . But when it hits about 1800 RPM's she takes off . I have no mods except the air cleaner though .
Scott

 

Best power for me is 2000-2500 rpm going up a hill pulling the trailer with the 5" Cannon bellowing at the gassers in the right hand lane.
MAN it sounds good then!!!

 

dont be afraid to spin these motors, they like RPM's... 2000-2700 is fine all day.

 

per 2000 owners manual: sharp ramp up to max torque at 1500 rpm, 20 % drop from there and rather flat until 2200 with rapid decline after that to about 60% max values at redline.

HP is typical gaser curve except shifted to lower RPM values max HP at 2800

Torque crosses HP at 1750 rpm = most efficiency

I hear they modified the curves somewhat wider for the later models. Chips and mods move the curves elsewhere.

 

You can see hp & tq in relation to rpm.

 

kevin just looking at the curved torque line i can just hear that K31 spooling up

 

Love your new avatar there Kris.

 

Really? I would think that maximum efficiency would be at maximum horsepower.

 

Kel, maximum horsepower doesn't mean maximum efficiency. Horsepower is just a function of torque related to RPM. You can't feel horsepower, you FEEL torque. It's what moves the truck. (and cars, but slower) The point where the torque is highest is where you usually want to run the truck. The way i know it, on the OTR trucks the max torque is about flat from 1100-1800, (redline at 2100 usually) and that means at maximum torque is when no more oomph can be extracted from the engine. That means the turbo is producing sufficient boost, to fill the cylinders as much as possible, and the fuel has sufficient time to burn as completely as possible, to get the most efficient burn cycle out of the cylinders.

Here is a dyno run on my truck last spring with stock chip setting.



The reason the run is so short is that it was done in OD, with stock speed limiter that i didn't know was there.

 

Well, it is rear-wheel torque that you are feeling, and a 350 HP motor will generate more rear wheel torque than a 250 HP motor, given ideal gearing for each motor, even if the 250 HP motor has a higher peak torque rating. So in that respect, it is engine power that determines how much of a load you can move, and how fast.

But a motor like a diesel that has higher torque at lower rpms can thus be operated at those lower rpms, and so it uses less fuel, so I guess I agree to some extent with your torque=efficiency assessment.

 

Not sure I follow your logic on HP engine. The way I look at it, a 350 hp gas engine makeing 350 ftlb of torque is not going to out pull a 250 hp diesel engine making 500 ftlb or torque.

 

In identical trucks going the same speed, the 350 HP motor geared to be at its HP peak will move a heavier load than the 250 HP motor geared to be at its torque peak (or its HP peak, for that matter).

My GMC 4x4 with its 330 HP 400 ft-lb 383 stroker will out pull my 250 HP 525 ft-lb 7.3. The only problem is that it will have to be at 4,500 rpm or so to do it, so it will be really annoying and use lots of gas.

 

Thank you for the laugh. This statement really cracked me up.
Right out of high school I got a job driving a 2-ton single axle flatbed truck with a small block chevy engine with a 2 barrel carburator, a 4 speed transmission, and a 7.20:1 rear axle delivering ceiling tile.
Talk about a grinder!
They disabled the rev limiter on it so it would go more than 50 mph and we used to run that thing up to 65 or so.
The engine blew up once while I was there, fortunately not while I was driving it.