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Discussion Starter #1
Hi,
I have been finding myself driving up long slopes, both mild and steep at low speeds due to road conditions.


For example, yesterday out in the desert we had a 13 mile climb at about 10mph. We had the windows down to enjoy a morning breeze but was running the AC for our dog that was laying on the bed in the back where the windows do not open.


I was in "D" drive and the RPM hovered at about 1k. I began to smell a burnt heat coming from the running gear. I turned off the AC, switched to manual and spun the engine at 1.5k for the remainder of the journey back to the highway, the highway speed, and a refreshing thrust of forced air.


This is not the first time I have smelled the aroma of petro-toast when driving slowly up a hill for extended distances.


The Eco Boost is a delight on the highway, but I wonder if I need to be more careful when we are poking along on rough roads. At the very least I would like to learn what rpm to maintain when climbing slowly. It feels like the automatic D is lugging the system, maybe not the engine, but the drive line system.



We have a 3.73 gear in the rear. The payload is on the light side. The van is basically used as a big metal tent without any of the popular "build out" stuff that might weight it down.



It also occurred to me that we "trained" the shift points out on open road, but now often drive in a different manner.



The van is low mileage, with frequent full syn oil changes, and the drive train is clean with no oily residues etc.


Any thoughts.
 

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It sounds like you are, to us old manual trans drivers, lugging it, which is not good for the drive train. I would drop it down to M and switch it to a gear which keeps it around the 2K rpm range so their is plenty of coolant flow, oil flow, and air flow to keep it from overheating and the engine won't be straining as much.
 

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I like the feeling of awesome torque at low rpms that the ecoboost provides. I have also wondered if there may be more wear with the higher cylinder pressures running that way vs a higher rpm in a lower gear with less engine load. What is worse, higher rpms or higher cylinder pressures?



Mr T, possibly at a low speed with less airflow under your vehicle at 10 mph, 1000 rpm and higher cylinder pressures, and hotter exhaust your turbos may be running hot and heating up everything around them causing the odor you smell?
 

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It does it on flat ground too, I live in a small town with enforced 25 MPH speed limits (the cops do not like city people) and you have to put it in Manual to hold the lower gears or else you just lug the heck out of it.
 

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Discussion Starter #6 (Edited)
Thanks for the suggestions and comments.


I'll try to get in the habit of using the manual modes, but I am still seeking some informed consensus regarding an ideal rpm. 1.5k felt much better than the 1k the Automatic system used. Having grown up with manual shifting, 1.5k felt just about right, but I would like to have a more rational approach to the selection, than just relying on my sense of feel. I will try the suggestion to of 2k, but I think the engine's response felt a bit exaggerated at that spin rate so I would like to have a fact based understanding of why the 2k may result in less heat build up etc.


Any more thoughts?


Thank you for the suggestion to try tow mode, I will do so the next time we are driving in the conditions I described.


Thank you!








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Off road I am either in Tow/Haul or M. I don't think lugging at 1000 RPM is ever optimal for a modern gas engine. As a general rule I like to be at a minimum 1500 or above if the motor is loaded.
 

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Discussion Starter #8
As it happens, we drove 60 miles of gravel mountain roads in our other vehicle yesterday. Climbed from 4,000 to 11,000 feet. The road was rough and we like to drive slow, so 10-15 mph was our rate of progress.



The system was in "D" automatic drive the entire time and rpm hovered at 1.5k.


That car is a 2003 model, I wonder why our Transit with it circa 2017 computing system can't figure out what's best for its drive line?
 

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You can push the button to keep it out of 6th. You don't have to use manual mode. You can limit it down to 2nd if you want.
 

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I think it's rather telling that the curve is close to zero horsepower and torque at 2000 rpm. Lugging is very hard on an engine, I'd stay at 2500 so the engine has some responsiveness.
 

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Discussion Starter #13 (Edited)
I too think that it is rather telling that the curve is close to zero horsepower and torque at 2000 rpm.


Having the first hand experience of being in the vehicle as it overcomes inertia and starts from a dead stop at well below 1000 rpm, where this chart has illustrated the engine has zero torque and zero horsepower, I am left to wonder how accurate such a chart can be.


I think that is one of those self serving charts made to scare people into buying something they probably do not need.



Running at 2500 rpm while driving at 10mph, due to rough road conditions in the outback of the Utah desert, seems like overkill, especially because you can not actually drive that slow at 2.5k in first gear.




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Discussion Starter #14
How is lugging any harder than full throttle?

Good question.


I had a Honda Odyssey as a do it all daily driver/camper van for 19 years. That thing had the V6 in it and it ran at 1k rpm for most of its life. It could also rev up and accelerate like a sports car, but Honda's engineering team didn't think it had to spin any faster then it needed to when you were driving in real life scenarios, and the engine was still strong and happy when we sold it. In fact, when we bought the Transit in 2017, I kept driving the Honda as a daily because I liked driving it.


The thing is, the Honda never smelled funny after a long slow climb, so I never had to ask about it.


The Transit is trying to tell me something.
 

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The issue with lugging / low engine speed is very high cylinder pressures with low air flow. The low airflow tends to over heat the exhaust valves and the turbo. That may be why you smell something.

Given the option, it is always good to try to operate above 2000RPM. It is just kinder to the engine.

Ron
 

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Given the option, it is always good to try to operate above 2000RPM. It is just kinder to the engine.
That makes me wonder why the Ford engineers program the transmission like they do, because it often shifts before 2,000 rpm :nerd:
 

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Discussion Starter #19 (Edited)
Gear--1000rpm-----1500rpm-----2000rpm-----2500rpm

1-----5.36mph-----8.04mph----10.72mph----13.39mph
2-----9.55mph----14.32mph----19.10mph----23.87mph
3----14.70mph----22.05mph----29.40mph----36.75mph
4----19.60mph----29.40mph----39.20mph----48.99mph
5----25.68mph----38.53mph----51.36mph----64.20mph
6----32.38mph----48.57mph----64.76mph----80.95mph








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