Ha! I even made sure my John Deere 1020 (1969) was gas. Don't need the extra complications of diesel.

 

 

I have a few Yanmar powered Deeres as well. They are crazy reliable and are incredibly well engineered.

 

I know it's an old thread, but I found this comment interesting, because I've been arguing over at PS.org that if I were ever to go from my 6-spd 7.3 to a modern truck, it would be a 6.2, not a 6.7. You know why? It's the same reason that I chose the 7.3. I feel the engine and transmission are the most reliable/affordable combo currently in production!

 

No. A 7.3 will not out pull a 6.2. People confuse torque with the ability to do work in a given amount of time, but that's actually the definition of horsepower. While a 6.2 will do more work in a given amount of time (hp), the 7.3 will do it more efficiently (mpg), and while I see people marveling at the 6.2 going 400k, I know the 7.3 has examples over 1M miles. So, given that I already own one, I'll still with the 7.3 for now, even though I know the 6.2 pulls harder.

 

Try swapping in a cummins straight six into the modern chassis. NOW you're talkin'! With the modern ford transmission, and no emissions, that would be the truck to have right there although I think it would be illegal to run on public highways. Always wished ford could have used the cummins instead of the international navistar diesel. Oh well.

 

Chris 42163 is correct regarding power; it's work per time.

"Horsepower" is a somewhat silly, arcane term, but we all recognize it and what it infers. HP is merely a statement of torque at some applied rpm; nothing more or less. Many of us know the formula .... HP = (Torque x rpm) / 5252.
The "5252" is a constant that represents the conversion from "revs per minute" to radians per second. It's a means of converting UoM (units of measure) to account for rotation. HP is an attempt to describe "work" in the rotational sense, over a duration of chronology.
https://auto.howstuffworks.com/question622.htm
Torque of the engine is multiplied by the trans gears and the diff gears. That torque is then turned into "force" (mass x acceleration) at the road surface when you take the torque at the output axle and then correct for wheel radius at the contact point on the road. This gives you a thrust force that actually propels the truck forward. Despite what many folks think, Torque is a form of work, not power. Read on ...

"Work" (in real definition of physics) is simply this: W = F x D, or work is force x distance. If two trucks with different engines (6.2L vs 7.3L) pull 10,000 pounds up a 500' incline, they both did exactly the same amount of "work" because they moved the same load for the same distance. The type engine does not matter in a real "work" formula.
- work in a linear fashion is this: force x distance (example shown above; you move 10,000 pounds up 500 feet of incline, you've done 5,000,000 lb-ft of work).
- work in a rotational fashion is still this: force x distance, but uses the term "torque" (example ... a wrench that is 2 foot long and has 100 pounds of force applied develops 200 "ft-lb" of work potential).
- because "work" is a multiplication mathematical formula of force x distance, you can use either term because the formulation does not alter the output (ie ... "ft-lb" or "lb-ft "are both proper terms because "a" x "b" is the same at "b" x "a")
- There are two types of work; potential and realized. This is what confuses a lot of folks especially when it comes to rotational work (torque). An engine spinning at 1,000 rpm may make 200 fl-lb of torque. But if I put 100 pounds of force on a 2 foot wrench, I'm still making 200 ft-lb of torque. One is in motion and the other is potential, but they are BOTH the correct expression of force in rotational effect. The torque made by the engine (200 ft-lb) is no more or less than the torque applied to the wrench (200 ft-lb).

"Power" is how fast work gets done. Power is work measured over a standard of time; Power = work/time. Or we can input the force formula into the power formula .... Power = (Force x distance) / time.
One truck can be more "powerful" than another, depending upon how quickly it can do the work. If the two trucks in the example above still pulled that 10k pounds up the 500' incline, but one truck got there faster than the other, then it would be more "powerful" because it took less time to do the same work.



Ahhhhh .... high school physics. I knew it would come in handy some day.

 

Do a some mods to a 7.3 and it will easily out pull a 6.2.

 

Awesome post. At the end of the day, it is always torque that moves the load, even if it is a light truck with no load at all. Now the question becomes: is it worth the cost and maintenance to own and operate a diesel? For some, the answer is definitely "yes". For most, the answer is without a doubt "NO". The big four, initial cost, MUCH higher maintenance costs, emissions, and substantially higher fuel cost that offsets the slight advantage in fuel economy, must be offset enough load dependent to justify the downsides to owning / operating a diesel.

 

True, but you've changed the inputs and so the output is understandably changed. You mod a 7.3PSD and it will out-pull a stock 6.2 gasser.
The 7.3L already has a stock power-adder; a turbo. So you modify the injectors, the ECM programming, etc and viola .... more torque from the diesel.
But what happens if you mod a 6.2L? You can re-balance the equation.
How about we add a blower or turbo to the 6.2L and retune the gas ECM and see where we're at?

Apples to apples; that's the fair way. A stock 6.2L essentially can pull what a stock 7.3L can pull.

 

It takes a lot more money to add power to a6.2 or any gas engine than it does a 7.3. Just a tune can get 100 HP or more out of a 7.3. The best performance upgrade for a 6.2 truck and most other gas trucks is lower axle gears.

 

maybe so, but how much power do you need? the factory 385 HP on my 2014 is way more than i will ever need.

 

I'm not sure what prompted the physics lesson, and I am getting more and more impressed as people really are starting to understand the difference more than they used to. However, this statement is false. Torque, while sharing a similar unit notation, is in no way work. It's a force applied at a distance about a fixed axis. It's best to think of it as rotational force, but just as linear force is not linear work, neither is torque rotational work. Linear force applied over a distance is work. Torque applied over an angle is rotational work.

 

This discussion of modding a 7.3 to pull more kind of misses the point for me. The power is not the limiting factor on the gen 1 PSD. My guess is that the factor limiting GCWR to 20k lbs is probably the brakes. I know there are passionate enthusiasts here who like to race another truck while pulling a load up through the Rockies, but that's just not me. I'll drop a couple gears and be happy trucking right on up any interstate hill at 60 mph at the top of 3rd (ZF6). The important parts to me are reliability, which modding doesn't help, fuel economy, which modding (not even tuning) doesn't help, longevity, which modding doesn't help, and safety, which modding can help (exhaust brake, OL springs, brakes, wheels/tires).

Now, to entertain the modding discussion to some extent, I'll have to side with the 6.2 again. In safety of stock form, it's putting down 150hp more than my 7.3. Yeah, a chip and a couple minor mods can get me there, but am I going to be comfortable putting all that power down going up a steep grade under load? I don't think so. Mine is stock, but I'm of the understanding that the pyrometer starts heating up pretty quickly when it's under that much strain. No thanks, in stock form I can mat the throttle all day without a worry, as long as I keep the RPM up. When I bought the truck and pulled nearly 20k lbs gross, I was worried about doing that through the Mountains, but the concern was not warranted, because I've gone through the Rockies and Appalacians pulling 17-20k lbs a few times, and have never wished for more power.

 

Another thing between the 6.2 and the big V8 diesels: look under the hood of each. Observe that there is NO room in the space around the engine with the V8 diesels to be able to work on anything. It's all just jam-packed in there and of course on the old 7.3s, the cab had to be lifted to do anything to the injectors or turbo etc. What a pain. Now look under the hood of a 6.2 and wow! What do you see? That's right, plenty of room all around the engine for access to everything. Sweet! And BTW no exhaust gas recirculation. For anyone who does their own basic maintenance, the 6.2 wins hands down.