Towing with previous generations?
07-12-2018, 12:37 PM
#11
Senior Member
07-12-2018, 12:42 PM
#12
If the EcoBoost is hyped as such a great tow beast, why does it start making max torque in the lower RPM range?
I am going to assume you meant this:
The reason the EcoBoost is such a great towing truck is because it starts making max torque very low in the RPM band.
Don't come at me with stuff like "My point exactly Captain Obvious" when you are the one who is struggling to articulate a point.
07-12-2018, 12:44 PM
#13
On an interesting side note, my engine monitor system has a torque at the transmission shaft PID. Its fun to watch even on the 6.7 diesel. We all get hung up on an engine making XXXlbs of torque at a given RPM, but they only do that at WOT pulling against a load. Part throttle cruising numbers are way down from that. For instance my peak number per the book is supposed to be 860 at 1600 rpms. It will at WOT pass that by almost 100lbft per the computer and maintain over that up to say 3k, then it tails off. At part throttle 1600 to 2500 rpm, it can show as low as 375 to mid 400s, start pulling a hill, turbos spool, and throttle applies on cruise control and you can watch it build torque on the monitor.
Also something to keep in mind is that HP is a function of torque, so the reason the 5.0 pulls so strong on the highway is that its torque band is maybe not as high as the eco at its peak, but is a gradual steady building broad curve. When I had my 5.0, it always pulled very strong on the highway and the truck and trailer combo was perfect even at 8k or more loaded. It always maintained speed very well at 2500 to 3500 rpms in either 5th or 4th gear, depending on the grade. The old 5.4 was bottom end based and fell on its nose as the rpm built, the 5.0 pulls strong all the way up.
Also something to keep in mind is that HP is a function of torque, so the reason the 5.0 pulls so strong on the highway is that its torque band is maybe not as high as the eco at its peak, but is a gradual steady building broad curve. When I had my 5.0, it always pulled very strong on the highway and the truck and trailer combo was perfect even at 8k or more loaded. It always maintained speed very well at 2500 to 3500 rpms in either 5th or 4th gear, depending on the grade. The old 5.4 was bottom end based and fell on its nose as the rpm built, the 5.0 pulls strong all the way up.
Assuming all else equal:
One truck that produces 200 hp at 2000 rpm is making 525 ft-lbs.
Another truck the produces 200 hp at 4000 rpm is making 262.5 ft-lbs.
If both trucks are traveling at the same speed then the one at 4000 rpm MUST have 2x the gear reduction. 2x the gear with 262.5 ft-lbs produces 525 to the wheel, same as the first truck. Both trucks will pull the same trailer at the same speed up the same hill.
This is why a 180hp/369 ft-lbs Duramax Colorado gets its butt kicked climbing by a 305 hp/269 ft-lb V6 colorado. and why a 240hp/420 ft-lb Ram Ecodiesel gets its butt kicked by a 365hp/420 ft-lb ecoboost(and every other V8 and ecoboost there is in a 1/2 ton truck).
The only thing interesting about torque is where its located in the RPM range as it tells you how that engine will tow at low speeds. even though an engine may produce 500 ft-lbs at 8000 rpm and make a shed load of HP, if it only makes 100 ft-lbs at 2000 rpm's I dont want to tow with it. At the same time, if an engine makes 500 ft-lbs at 2000 rpm but craps out above that and only makes 100 ft-lbs at 3000 rpm, I dont wanna tow with that either. It will tow fine on flat ground, but the second you start up a hill it doesnt make enough HP. This is the exact problem with the small diesels in the mid-sized and 1/2 ton trucks. Decent torque, no HP.
This is why I feel the ecoboost is such a great engine. It makes the torque of a diesel while not crapping the bed above 3k rpm. My other vehicle is a 2.8L Jeep Liberty diesel and this is exactly what it does. The torque curve drops off so fast after 3k rpm that the HP curve is flat. Even though it produces 400 ft-lbs of torque, it struggles to pull my trailer up a hill, while my ecoboost does it with ease at 3k.
Last edited by mass-hole; 07-12-2018 at 12:48 PM.
07-12-2018, 12:48 PM
#14
Senior Member
07-12-2018, 12:53 PM
#15
07-12-2018, 06:13 PM
#16
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Instead of relying on our perspicaciousness, try to be more perspicuous.
07-18-2018, 07:19 PM
#17
FORD lifer
We are so spoiled by our modern trucks.
Lets go back to 1979 - we had 351M and 400M engines that made like 154hp and 158 hp. And they got about 10mpg.
If you were pulling a heavy trailer it would be foot-to-the floor on any long hills, and the old man would tell me to let up on it and let it slow down, or I'd "knock the rods out of it".
The only current engine I'm not sold on, is the 2.7 eco, and I can't prove it, but I think they are really overworked.
Lets go back to 1979 - we had 351M and 400M engines that made like 154hp and 158 hp. And they got about 10mpg.
If you were pulling a heavy trailer it would be foot-to-the floor on any long hills, and the old man would tell me to let up on it and let it slow down, or I'd "knock the rods out of it".
The only current engine I'm not sold on, is the 2.7 eco, and I can't prove it, but I think they are really overworked.
07-19-2018, 02:07 AM
#18
We are so spoiled by our modern trucks.
Lets go back to 1979 - we had 351M and 400M engines that made like 154hp and 158 hp. And they got about 10mpg.
If you were pulling a heavy trailer it would be foot-to-the floor on any long hills, and the old man would tell me to let up on it and let it slow down, or I'd "knock the rods out of it".
The only current engine I'm not sold on, is the 2.7 eco, and I can't prove it, but I think they are really overworked.
Lets go back to 1979 - we had 351M and 400M engines that made like 154hp and 158 hp. And they got about 10mpg.
If you were pulling a heavy trailer it would be foot-to-the floor on any long hills, and the old man would tell me to let up on it and let it slow down, or I'd "knock the rods out of it".
The only current engine I'm not sold on, is the 2.7 eco, and I can't prove it, but I think they are really overworked.
07-19-2018, 07:08 AM
#19
That's pretty awesome, I would watch that all day and most likely drive my truck into a wall due to being so distracted lol.
Sure you have thought of this, but the "extra" 100lbft you are seeing at the transmission shaft are most likely because the 860@1600 RPM book figure is measured at the wheels. 10 - 11% drive train loss isn't bad at all.
Sure you have thought of this, but the "extra" 100lbft you are seeing at the transmission shaft are most likely because the 860@1600 RPM book figure is measured at the wheels. 10 - 11% drive train loss isn't bad at all.
07-19-2018, 09:18 AM
#20
FORD lifer
Im sure the engine exists to help with CAFE standards, and that it will run fine for a while. But I wouldn’t have one, and if I did I wouldn’t be towing anything heavier than a ATV trailer with it. They are not Cummins Cargomaster Diesels
