How much better is diesel at towing?

[kdauto]

https://www.caranddriver.com/news/a1...he-difference/

It's all math.

You can't have one without the other. Some people are fixated on MAX torque and MAX HP numbers. What is more important is how flat and/or how early the torque and HP curves approach peak numbers (flat curve). Having 480HP in a narrow powerband of a few hundred RPM vs one that can obtain 400HP and hold it for 1500-2000RPM is more useful.

[Dave Pelletier]

Originally Posted by kdauto

https://www.caranddriver.com/news/a1...he-difference/

It's all math.

You can't have one without the other. Some people are fixated on MAX torque and MAX HP numbers. What is more important is how flat and/or how early the torque and HP curves approach peak numbers (flat curve). Having 480HP in a narrow powerband of a few hundred RPM vs one that can obtain 400HP and hold it for 1500-2000RPM is more useful.

Exactly

[GME3470]

I have owned a 2002 7.3l Ford and a a 2011 6.6l Chev Duramax in the past and they both were great trucks. But the last two trucks I purchased were Fords with the gas engines--2017 6.2l and just recently a 2022 7.3l. The reason I switched to gas was based on the fact that we were only pulling travel trailers with less than a 10K GVW and that the extra expense for the diesels just didn't pencil out.

We have put about 12k miles on the 2022 7.3l, 4.30 rear end, 10speed and are totally impressed with the performance and fuel burns. In no wind, level freeway it gets a hair over 10mpg (10.2-10.3) and of course pulling big grades it falls way off that. I really haven't figured what an overall average for a trip with the trailer and plan to do that. The book says it has a 38 gallon tank and that has been plenty of fuel for the legs we drive.

As someone mentioned the new gas truck engine sound pulling a grade is not as noticeable as in the past. This truck has a good torque curve and pulls the trailer up big grades without issue. Engine braking is also just fine. With diesel being about a dollar a gallon more, the difference between operating gas vs diesel is certainly narrowed. And no DEF! But, everybody needs to buy what they want, not necessarily what they need.

[4x4ord]

Originally Posted by Dave Pelletier

I don't have time to write a novel on my phone but that's simply not how it works.....if it did, the gassers would out perform all diesels. The peak number is all that matters and the Cummin's may peak early (which is a good thing) but it remains at that level until 3,000 rpm or so.

Dave

I'm not sure what you're suggesting, but yes the power an engine makes will determine the potential speed at which it can tow a load up a hill. On the other hand crankshaft torque without considering rpm is quite meaningless. Saying my engine makes 800 lbft of torque is exactly as meaningless as saying my engine makes 4000 rpm.

[4x4ord]

Originally Posted by Dave Pelletier

For drag racing hp matters; for towing it's almost all about torque. Torque tells you the power an engine has and hp is calculated from torque x rpm; which makes makes torque a far better metric for comparing towing capability between gas and diesel engines.

The Cummins HO has about the same HP as a 7.3 gas, but over double the torque....hook them both up to 30,000 lbs and head up a 7% grade and let me know what happens.

Dave

Think about what your saying. You are claiming torque is the key metric when it comes to towing a trailer up a hill .... Then to prove your point you're suggesting that we could take two engines with similar horsepower and the one which makes over twice as much torque as the other should be able to beat the low torque unit up the hill..... the crazy thing is that even with over twice as much torque there is no guarantee that the 6 speed Cummins will out pull a 10 speed 7.3 gasser. At 11000 ft I'm sure the turbocharged engine would win ... however, at sea level it's not so obvious.

Now lets look at this the other way: If torque were truly the key metric and HP were of little value you should be offering to put a 1075 lbft diesel engine making 430 hp up against a 800 lbft 800 HP supercharged Godzilla.... In this case the higher torque engine would be so far behind the gasser it wouldn't even be funny.

[Ray,IN]

When discussing this MPG topic, then adding in fuel cost, one must also add the cost of DEF for recent model diesel engines.
One example of new gas engines is GM's colorado and canyon pickups brand new 2.7 turbocharged gas engine: https://www.motorbiscuit.com/better-...s-gm-engineer/


That 3.7 engine is truly a workhorse engine, not some highly-modified aftermarket godzilla type engine that would likely come apart in the long haul.

[tuffr2]

HP vs Torque - my understanding which could very well be wrong.

Torque gets the load moving and HP keeps the load moving. So from 0 mph to 70mph torque is more important. But once going 70 mph HP takes over. At 70 mph you are using less torque and more HP. This of course is on level roadway.


Going up a mountain you will be using both HP and Torque.

[laj]

Simple. Torque is how much your going to move, HP is how fast your going to move it.

[4x4ord]

Originally Posted by tuffr2

HP vs Torque - my understanding which could very well be wrong.

Torque gets the load moving and HP keeps the load moving. So from 0 mph to 70mph torque is more important. But once going 70 mph HP takes over. At 70 mph you are using less torque and more HP. This of course is on level roadway.


Going up a mountain you will be using both HP and Torque.

If you want to better understand power and torque, here are some things to think about:

Power has a unit of time to it. It is the rate of doing work. Torque is a unit of force ….when you measure torque you’re not concerned with time.

Power can be determined by measuring rpm (that’s where the unit of time comes from) and measuring torque. Multiplying the two numbers together gives power (Dividing that number by 5252 will yield HP)

A truck’s power could also be determined by measuring the length of time it takes for the truck to tow a weight up a hill.

The torque needed to move a heavy truck and trailer up a steep hill can be calculated using the weight of the trailer and the incline of the hill…. Time is not a factor.

So, in a vacuum the amount of torque required to pull a trailer/truck up a hill at 50 mph is identical as the torque required at 100 mph.

Torque can be multiplied through gearing. If an engine is producing 400 lbft of torque at the crankshaft @1500 rpm it can be run through gears to get 1200 lbft @ 500 rpm. Power is not changed through gearing.

Both torque and power are produced when an engine burns fuel. The more fuel an engine can burn per revolution the more torque it will make. The more fuel an engine burns per second … the more power it will make.

[deserteagle5]

Originally Posted by 4x4ord

Think about what your saying. You are claiming torque is the key metric when it comes to towing a trailer up a hill .... Then to prove your point you're suggesting that we could take two engines with similar horsepower and the one which makes over twice as much torque as the other should be able to beat the low torque unit up the hill..... the crazy thing is that even with over twice as much torque there is no guarantee that the 6 speed Cummins will out pull a 10 speed 7.3 gasser. At 11000 ft I'm sure the turbocharged engine would win ... however, at sea level it's not so obvious.

Now lets look at this the other way: If torque were truly the key metric and HP were of little value you should be offering to put a 1075 lbft diesel engine making 430 hp up against a 800 lbft 800 HP supercharged Godzilla.... In this case the higher torque engine would be so far behind the gasser it wouldn't even be funny.

So...you are suggesting that all those 18-wheelers pulling heavy loads up and down our highways need to get rid of those low-rpm, high-torque diesels and change over to gas engines?

[4x4ord]

Originally Posted by deserteagle5

So...you are suggesting that all those 18-wheelers pulling heavy loads up and down our highways need to get rid of those low-rpm, high-torque diesels and change over to gas engines?

Absolutely not. High torque engines are excellent engines for towing. And like you, I might even prefer towing with an older diesel vs a more powerful newer gasser.

[4x4ord]

Originally Posted by deserteagle5

So...you are suggesting that all those 18-wheelers pulling heavy loads up and down our highways need to get rid of those low-rpm, high-torque diesels and change over to gas engines?

Absolutely not. High torque engines are excellent engines for towing. And like you, I might even prefer towing with an older diesel vs a more powerful newer gasser. I suppose what am saying is if I’m climbing a hill with a 2010 diesel and I see a new 7.3 gasser behind me pulling the same trailer as mine I’ll pull into the right hand lane and let him pass.

[Dave Pelletier]

Good to know that a 7.3 gasser with 430 hp can out pull a 6.7 HO Cummins with 420hp despite the Cummins having 1075 ft lbs vs. 475 ft lbs. 😅

Despite all the rhetoric, to answer the OP's question; the best of the best new gas engine HD pick up is about on par with towing compared to a 2006-ish diesel as long as you aren't considering mileage.

Dave

[dbircky]

I’ve never horsepowered a bolt to 400. But I’d bet anyone torquing a bolt to 400 will admit that’s work.