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Discussion Starter #1
I would like to understand something...

IF the EcoDiesel makes more torque...has the same frame how does the HEMI have more towing capacity?

I'm not sure how horse power matters in this equation, though I do see how rear end gears and transmission could enter the math problem but that plays into torque, and we already know who wins that battle.

So whats the missing link here?
 

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I think it's a weight factor if I remember correctly. Diesel is heavier than the hemi so more sprung weight as they call it contributing to less overall weight left for towing. Or in my mind that's how it works. Anyone feel free to correct me. Just out of curiosity what's ur gvwr. My hemi crew is 6900lb

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Cooling and HP.

I do believe that the current standardized rating systems take into account how fast the vehicle can complete certain tasks and what weight they can do x task without downshifting etc. where HP would come in more. We all talk about torque, but the reason the ecodiesel seems slow... at least to me when compared to other vehicles is because it only has 240 HP, similar to a v8 of the 90's.
 

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The way most manufactories calculate tow ratings now is by using SAE J2807. Our ecodiesels failed hard due to the crap cooling system which results in a derate condition during the test. If fca had designed the cooling system better it would be closer to the hemi.
 

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The new 2020 ED's increased towing capacity is primarily related to the improved cooling. The intercooler was moved into the bumper below the radiator and condenser so FCA engineers eliminated the "stacked cooling" effect - basically too many cooling components stacked on top of each other thereby decreasing the effectiveness for all of them.

The HP and torque for the new ED are increased somewhat (near the same as a GDE tune on the current engine) but it's the cooling improvements that give the biggest boost to towing capacity.

I've been of the mind that unless I'm putting my truck in a situation in which I will be at or over the derate ceiling I can tow essentially the same weight as the same truck with a Hemi. The ED is about 80 pounds heavier than the Hemi IRRC but there's no difference in the frame, brakes, etc. between my ED and the Hemi version - the diesel's cooling is the limiting factor. I'm not stupid enough to keep my foot mashed to the floor on the skinny pedal just to climb a mountain faster than an unloaded semi so I'll manage the cooling myself. A trailer isn't going to wag the dog any more being towed by my ED than the same trailer with a Hemi.

My 2 cents - others' opinions my vary widely.


Bob
 

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Discussion Starter #8
cooling, interesting...now with the GDE tune, is the truck essentially operating (or have the ability to) at a cooler temperature under load? Do we think we gain that 1200lbs back with the GDE tune?


I drove the Eco 2.5hrs to pick up a tonneau cover.

When I arrived I took a look at my readouts:
Trans temp was 190
Coolant was 200
Oil temp was 220
Oil pressure 30psi

This was empty of course.
 

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cooling, interesting...now with the GDE tune, is the truck essentially operating (or have the ability to) at a cooler temperature under load? Do we think we gain that 1200lbs back with the GDE tune?


I drove the Eco 2.5hrs to pick up a tonneau cover.

When I arrived I took a look at my readouts:
Trans temp was 190
Coolant was 200
Oil temp was 220
Oil pressure 30psi

This was empty of course.
The gde tune runs hotter in cylinder under higher loads than stock which is part of why it is so efficient. So no it well actually derate slighty quicker do to more heat being produced.
 

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Discussion Starter #10
The gde tune runs hotter in cylinder under higher loads than stock which is part of why it is so efficient. So no it well actually derate slighty quicker do to more heat being produced.
Sooo, whats the fix?

what is the ideal mods to get the 1200lbs back? Is it cooling the friction fluids or simply a better radiator and fan set up? OR is the block/head coolant channels just too small to make a difference?
 

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The GDE tune will not affect the cooling capability of the radiator so it will have no effect on towing capacity.

If you want to get really detailed, I do notice lower egts with the GDE tune compared to stock, so technically the engine is not producing (or more likely wasting) as much heat and therefore the radiator doesn't have to work as hard. But this will have little or no noticeable effect on towing capacity.

That's not to say the GDE tune isn't worth it, it just isn't going to give you that specific benefit. You could try the GDE thermostat though.

If you're really concerned about it for towing, pair the GDE Hot tune with the trans tune and the thermostat for the best results.

Your numbers look similar to mine, except the oil temp, mine is usually 212 with no load. It will climb to 220 easily though so your oil temp probably isn't anything to worry about.
 

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Discussion Starter #12
The GDE tune will not affect the cooling capability of the radiator so it will have no effect on towing capacity.

If you want to get really detailed, I do notice lower egts with the GDE tune compared to stock, so technically the engine is not producing (or more likely wasting) as much heat and therefore the radiator doesn't have to work as hard. But this will have little or no noticeable effect on towing capacity.

That's not to say the GDE tune isn't worth it, it just isn't going to give you that specific benefit. You could try the GDE thermostat though.

If you're really concerned about it for towing, pair the GDE Hot tune with the trans tune and the thermostat for the best results.

Your numbers look similar to mine, except the oil temp, mine is usually 212 with no load. It will climb to 220 easily though so your oil temp probably isn't anything to worry about.

Wasn't worried, just posting them for someone to verify they are as expected. (so thanks)

Jeez, I hadn't even thought about a simple thermostat change. That might not be the best in winter though.

I have nothing specific here to tow. I'm simply interested in why EcoDiesel was rated 1200lbs less, and how to recover it, if desired.
 

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GDE developed an intercooler relocation kit for their truck. They moved the intercooler down below the radiator behind the bumper. They also used their turbo kit with this setup. Would have to ask them to post the details on their testing. This was from like 2015 I believe.


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Horsepower does the work to tow, not torque. Pulling the same weight up the same hill at the same speed requires the same horsepower from the engine. It does not require the same torque from the engine. Gears increase the torque the engine makes and delivers it to the wheels. Gears cannot increase horsepower. The concept of horsepower contains a time element to measure the speed at which the work can be done. Torque does not have a time component. The hemi is likely to be in a lower gear and spinning at a higher RPM to develop the horsepower necessary to pull the load and the ecodiesel is likely to be spinning slower to develop the horsepower to get up the hill.

to take it to the extreme and assuming no losses in transmissions etc a 1000 ft lb 1 horsepower engine and a 1 ft lb 1000 hp engine could theoretically pull the same load. The 1000 hp engine would just do it 1000 times faster than the 1 hp engine.

A lot of the world is confused about torque and horsepower.

The comments above assume the engine can develop its horsepower over the full rpm range and can withstand it and get rid of the excess heat. The heat issues for the Ecodiesel mentioned above are correct.
 

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I have wondered if it would be possible to retrofit the 14-19classic trucks with the new intercooler/radiator set up from the 2020 model to relieve cooling issues. Im sure it would be cost prohibitive for the gains.

In the end you can almost completely solve the issue of over heat with an aftermarket oil/air cooler. An appropriately sized cooler will keep the oil in check and the reduced cooling load on the radiator from the removal of the water/oil heat exchanger will keep the coolant temps down.

Im sure unstacking the intercooler couldn't hurt, if the intercooler is behind the radiator im sure it would help with some performance as well.
 

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What makes zero torque does not move.

There is no horsepower without sufficient torque.

Howie try as you have you have never debunked that or talked your way around that. Practically speaking it takes both. Your second sentence doesn’t say anything. Of course towing the same weight up the same hill at the same speed requires the same horsepower. Towing more weight up that hill requires more torque or more gear with more rpm to make up for insufficient torque.

Once sufficient torque is applied to move x weight with x gear then what horsepower it’s making at that rpm or rather through the sufficient torque rpm range horsepower will determine how fast it will move it. You don’t need just horsepower to tow you need a sufficient amount of torque (and practically speaking we do not have infinite gears) plus horsepower the way I understand it. Once you have sufficient torque for the gear the more available horsepower the better and faster you can accelerate it. And again I have great respect for your knowledge perhaps we just never see this the same.

Pj your temps look normal for this engine. Ajb’s list is good. I might add from a Big Horn a simple switch to a less restricted grill such as the honeycomb style found on a Tradesman or SLT has been proven by GDE to help. Having done the swap I can tell you it helped on mine when towing. Not huge but noticeable. Last more speed requiring overcoming more drag puts dramatically more load on the cooling system. Towing a big box TT going from steady state 65 to steady state 70 mph requires a lot more fuel (percentage wise) which you can see in your gauge cluster and you can watch the coolant temp rise also.

As MAS stated the ultimate we have now is the large aftermarket coolers that run about a grand. Last you also have the fall back of limiting your throttle input to limit your rpms. At 3,000 rpms or less it’s very hard to get it hot enough to de-rate. It may slow a little towing that grade than you would like but the computer won’t pull fuel & power and slow you way down. I’d rather tow the grade at say 55 (3,000 rpms) than 65 only to be de-rated down to 15 mph near the top, only because I would joy take my foot off the floor.
 

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I have been considering swapping out the front bumper with a '09-'12 bumper which had a slot across the front perfect for airflow to an intercooler. then relocate the intercooler in the bumper. This would offer the same benefits as the 2020 ED and the cummins which already have the intercooler in the bumper.

2009_dodge_ram-pickup-1500_regular-cab-pickup_slt_fq_oem_1_500.jpg
 

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Sooo, whats the fix?

what is the ideal mods to get the 1200lbs back? Is it cooling the friction fluids or simply a better radiator and fan set up? OR is the block/head coolant channels just too small to make a difference?
I fixed mine with a huge external oil cooler. Keeps oil and coolant temps in check when towing heavy.

My next mod will be to move the oil cooler from in front of the cooling stack to down behind the front bumper. Lots of open real estate behind the bumper.
 

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What makes zero torque does not move.

There is no horsepower without sufficient torque.

Howie try as you have you have never debunked that or talked your way around that. Practically speaking it takes both. Your second sentence doesn’t say anything. Of course towing the same weight up the same hill at the same speed requires the same horsepower. Towing more weight up that hill requires more torque or more gear with more rpm to make up for insufficient torque.

Once sufficient torque is applied to move x weight with x gear then what horsepower it’s making at that rpm or rather through the sufficient torque rpm range horsepower will determine how fast it will move it. You don’t need just horsepower to tow you need a sufficient amount of torque (and practically speaking we do not have infinite gears) plus horsepower the way I understand it. Once you have sufficient torque for the gear the more available horsepower the better and faster you can accelerate it. And again I have great respect for your knowledge perhaps we just never see this the same.

Pj your temps look normal for this engine. Ajb’s list is good. I might add from a Big Horn a simple switch to a less restricted grill such as the honeycomb style found on a Tradesman or SLT has been proven by GDE to help. Having done the swap I can tell you it helped on mine when towing. Not huge but noticeable. Last more speed requiring overcoming more drag puts dramatically more load on the cooling system. Towing a big box TT going from steady state 65 to steady state 70 mph requires a lot more fuel (percentage wise) which you can see in your gauge cluster and you can watch the coolant temp rise also.

As MAS stated the ultimate we have now is the large aftermarket coolers that run about a grand. Last you also have the fall back of limiting your throttle input to limit your rpms. At 3,000 rpms or less it’s very hard to get it hot enough to de-rate. It may slow a little towing that grade than you would like but the computer won’t pull fuel & power and slow you way down. I’d rather tow the grade at 55 than 65 then be slowed down to 15 mph near the top only because I would take my foot off the floor.
Vern,

I agree it takes torque to make horsepower and what has 0 torque cannot move anything. I don't think I ever tried to argue otherwise. Yes it takes both, however the torque can be multiplied by the transmission and final drive gearing and the horsepower cannot be increased the same way. You are right the second sentence makes no sense and is a disaster. What I was intending to say is towing the same load up the same hill at the same speed with two different vehicles with different engines with different torque and hp characteristics takes the same horsepower from the engine but doesn't require the same torque from the engine. Then I think the rest of that paragraph hangs together. I should be more careful and proofread what I write from the view of a skeptic. I guess I lost that practice after retiring.

In the days of manual transmissions with no torque converters torque was a bigger issue. As a past heavy truck driver (I think I am right there) you will recall the days of the road ranger 13 or whatever speed transmission and the detroit diesel which made decent horsepower but was very peaky on torque and hp vs other diesel engines of the day. AMongst the best was the Mack with what I think was their Maxidyne engine which was introduced in 1967. It only had a 5 speed transmission. and provided maximum horsepower over a wider range of engine speeds than any other standard diesel engine of its day. The engines design leveled the horsepower curve and as a result, increased fuel efficiency and significantly reduced the need for shifting. I had an uncle that had couple as gravel dump trucks he had two things to say about them, one was "after a million miles I never wore out the clutch linkage or the shifting linkage' and the other was when you are shifting and clutch is in the engine isn't pulling anything-with the Mack it is pulling most of the time." The key of the Maxidyne was that a broad horsepower curve, not a broad torque curve is what made it do what it did which was quite revolutionary in its day.

Back to the main case, you are correct we do not have infinite gears and I am not a fan of the CVT transmission although it is technically an elegant solution. However with a torque convverter in front of our transmissions we do have the near equivalent of infinite gears because the torque converter essentially lowers low gear and effectively provides varying gear ratios outside of the transmission gears when it isn't locked up.

Anyhow, I am fighting a losing battle on convincing those that aren't conversant with the physics and being an engineer, writing isn't my best skillset either. In defense I do note that Jason from the engineering explained website cannot do this subject justice either.

Perhaps someone else can bail me out.

All the best Vern.
 

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The only way to fix the cooling system to raise the tow rating (which it technically wont anyways) is to add cooling capacity to the engine. The three biggest things would be a better radiator, better oil cooler aka one that could maintain a 10 degree delta, a lower temp thermostat and the fan set points to match. Now we dont have those options readily available other than the thermostat so it is easiest to install a larger oil cooler that uses ambient air to cool instead of rejecting that heat into the coolant. By just doing the oil cooler I lowered my coolant temps over 10 degrees and oil by over 30 degrees.
 
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