Ram 1500 diesel review

bimbert84 wrote:

wilber1 wrote:

The statement isn't wrong, it is torque that gets the job done, HP is the rate at which the engine is applying torque.

Sigh. It's torque at the wheels that gets the job done, not torque at the engine as the article said. I'm not sure what I can say to be any more clear.

In the same gear, more torque at the engine means more torque at the wheels. I don't know what could be more obvious.

wilber1 wrote:

I said, no one would argue the diesel is more powerful

Yes, you said "argue," which is ambiguous. It could mean "argue for" or "argue against." You meant it one way and I read it as the other.

-- Rob

No one means no one. No one has to include me, otherwise it wouldn't be no one. There is only one way to read it.

jus2shy wrote:

OK, Updated the spreadsheet.

Most excellent! The bottom two graphs are the ones that matter on the road. They should help everyone to see that delivered power is a varying function of vehicle speed, and that at speeds above 30mph or so, torque at the wheels is very similar for all three drivetrains.

Now all that remains is to add in the 3.0L Eco-diesel that prompted this thread. Except for very low speeds, it'll be significantly lower across the speed range. Why? Because it generates significantly less horsepower, which results in significantly less torque at the wheels.

-- Rob

wilber1 wrote:

The statement isn't wrong, it is torque that gets the job done, HP is the rate at which the engine is applying torque.

Sigh. It's torque at the wheels that gets the job done, not torque at the engine as the article said. I'm not sure what I can say to be any more clear.

wilber1 wrote:

I said, no one would argue the diesel is more powerful

Yes, you said "argue," which is ambiguous. It could mean "argue for" or "argue against." You meant it one way and I read it as the other.

-- Rob

RoyJ wrote:

Terryallan wrote:
Looking at the numbers. they were not that impressive.

No? Find another 5600+ vehicle that gets 24 mpg average.

A Range Rover weights that much and you're luck to get 15 mpg mixed...

I have a Touareg SUV AWD 3.0 TDI... 240 HP 406 ft lbs, 5000 #s... and it's getting 33 MPG on the highway, all day long, on summer diesel fuel. Mixed city and highway, I get around 27 MPG per tank. I live in the city of Los Angeles and I am retired, I schedule my driving to avoid rush hour stress and traffic at all costs.

Another factor that hasn't been mentioned yet is torque management in the lower gears. I would really be surprised if the 6.7 diesel produces all 800 ft./lbs. in first gear. That seems a sure way to twist off a driveshaft. I imagine the gas engines incorporate some sort of torque management as well, although in either case it really only would affect performance at low speeds.

It would also be interesting to see those spreadsheets comparing the Ecoboost to the Ecodiesel (makes me wonder if Ford and Ram use the same marketing department) since those engines are direct competitors.

Thanks for the input guys. It will be difficult to factor in TC stall in the gears, but you are right that there would be some multiplication there when rolling initially. I actually found a few torque charts online that I was able to put together to compare the HEMI, Ecodiesel, and the Ecoboost from previous work. Basically found a HEMI chart from some MAX Motors website that looked approximate and the Ecodiesel from some 4 wheeler magazine that had it posted. Again, I'm approximating the torque at a given RPM given the charts and this is what I came up with. So it's a fun analysis. I actually enjoy doing this kind of stuff when it comes to talking cars! Here's a link for those interested: New Spreadsheet

So it looks like the Ecodiesel (without assuming Torque Converter factors) has the advantage up to 15mph, then the HEMI just walks away afterward. But then there's a 150 or so HP disparity between these two motors. Now if the Ecodiesel put down 300 or so like the Cummins ISV going to Nissan. I wonder how much more closely they would be. This was still interesting to do and a good mental excercise for me.

I keep remembering stuff to edit. So the Ecoboost was done assuming 3.73 and mated to the 6R140 transmission(since its from the last comparison I did between the Ford motors). The HEMI and ECODIESEL are both assumed to have 3.92 rear axles and the 8 speed transmission. When looking at the 3.55 rear axle on the diesel, it was just painful to see the numbers fall so far from the HEMI. However, RAM has never announced if the diesel will be coming with the 3.55 or 3.92 on this truck. I actually wouldn't be too surprised to see this diesel come with 3.92 axles because it is a really high revving diesel motor. Redline on it is right around 5,000rpm.

Here's the Torque Table
MPH/HEMI/ECODIESEL/ECOBOOST
10- 6443| 8214| 5553
15- 6995| 7468| 6219
20- 7455| 6449| 6219
25- 7547| 4842| 6219
30- 6443| 4299| 6071
35- 5031| 3665| 5200
40- 4908| 3102| 3635
45- 4294| 2890| 3635
50- 3382| 2488| 3635
55- 3382| 2317| 3461
60- 3299| 2073| 3100
65- 3010| 1895| 2381
70- 2711| 1839| 2381
75- 2645| 1765| 2381
80- 2579| 1579| 2325

Here's the HP Table
MPH/HEMI/ECODIESEL/ECOBOOST
10- 152| 149| 125
15- 199| 212| 180
20- 289| 250| 240
25- 332| 225| 300
30- 383| 250| 340
35- 332| 242| 350
40- 381| 233| 246
45- 383| 250| 310
50- 332| 233| 340
55- 351| 250| 362
60- 381| 239| 350
65- 382| 233| 288
70- 371| 243| 320
75- 381| 250| 330
80- 390| 239| 351

Here's the gear shift table
MPH/HEMI/ECODIESEL/ECOBOOST
10- 1| 1| 1
15- 1| 1| 1
20- 1| 1| 1
25- 1| 2| 1
30- 1| 2| 1
35- 2| 2| 1
40- 2| 3| 2
45- 2| 3| 2
50- 3| 4| 2
55- 3| 4| 2
60- 3| 4| 2
65- 3| 5| 3
70- 4| 5| 3
75- 4| 5| 3
80- 4| 5| 3

Looking at these without the Torque Converter correction, it is interesting to see how much smoother the 8 speeds are , especially in the HP table. You don't get as much variance and the engine can keep working near it's peak which would give increased WOT performance.

Actually, thinking a little more, wouldn't a 2,000rpm stall on the torque converter just allow an engine to rev higher for a given speed? Like at 10mph, it'd rev at 4000 rpm instead of 2000, so you would just inject torque output (and horsepower) at that RPM for 10mph? Anyways, more things to think about and I don't feel like adding to this for the day (or week LOL). But I have noticed the higher gear count on the motors, the earlier the motors tend to lock-up. On my wife's Subaru, it's equipped with a CVT transmission and as soon as you hit 5mph, the converter locks up regardless of throttle input.

Lets keep enjoying a more civil gas vs. diesel conversation here :)

Taco wrote:
jus2shy,

pretty good analysis of what a truck can do at a specific speed. I want to point out one error. The gasser will never run full throttle below about 2k rpm. that is approx the stall speed of the converter. Also it will start with probably a 2:1 additional gearing from the torque multiplication of the converter which will taper off quickly as the truck starts moving.

That stall on the diesel is probably in the 1500 range and the torque multiplication is probably around 1.5:1

The ZF only uses the torque converter for launch from a standing start then it locks. It uses a first gear ratio of 4.69:1 and locks in every gear but reverse.

jus2shy,

pretty good analysis of what a truck can do at a specific speed. I want to point out one error. The gasser will never run full throttle below about 2k rpm. that is approx the stall speed of the converter. Also it will start with probably a 2:1 additional gearing from the torque multiplication of the converter which will taper off quickly as the truck starts moving.

That stall on the diesel is probably in the 1500 range and the torque multiplication is probably around 1.5:1

Get rid of the crew cab in the Dodge Ram 1500, drop some weight, get rid of the german transmission and put in a japanese Aisin 8 speed, with tiptronic style shifting, like in the Tourareg, Q7, Cayenne lineup, and you'll be on to something.

I use the same 3.0L 240 HP 406 ft/lbs of torque in a 5000 lb Touareg to tow a 4000 lb wet 21 ft travel trailer, and it suits my purposes just fine. You just can't underestimate this power train with the torque figures, if you get the weight down and the coefficient of drag down also on this truck.

I see 33 mpg empty, in AWD full time, and 16.5-18.8 while trailering. Dodge and the Motori motor, I hope, are headache free, seems like a great package to me. Test drive it and get back to us, but from a Travel trailer POV., if it's reliable, this is gonna sell like hot cakes, if folks will keep an open mind. Once you've towed with diesel, it's very, very hard to go back to a gasser.

For me, turbo diesel is a no brainer, every single time, be it sedan or tow vehicle. There is just no substitute for that low rpm torque, I am addicted to.


I will always give up higher rpm for torque and lower rpms. You lose in volumetric efficiencies the higher the rpm you run and more parisitic loss of HP to friction in the engine block too, in addition to huge fuel consumption rates and huge pumping loses in gas vs a diesel power plant.

OK, Updated the spreadsheet. I was actually very surprised to find that given the monster amount of power the Diesels make now a days that it stays ahead of the 6.2L. Note though, that this is the inferior tune that the Ford 6.7 had versus the F-150 tune of the 6.2 that just makes more power all over the place compared to the super duty tune. I selected the 3.73 rear axle on the gasser and 3.31 axle on the super duty since these are the most commonly sold rear axles out there. I also threw in a hypothetical if we had an ecoboost mated to the same setup as the 6.2L motor. Hopefully the formatted table below shows the same as the spreadsheet. Attached is the torque put down at the wheels after gear multiplication and such. The Diesel stays ahead for the most part but after 35mph, they're well close to each other. The ecoboost was an interesting one to put in there as well. Here's the full spreadsheet to compare with: Spreadsheet

Torque
MPH/Ford 6.7/Ford 6.2/Ecoboost 3.5
10- 9,658| 4,146| 5,553
15- 9,658| 4,442| 6,219
20- 9,658| 5,035| 6,219
25- 7,227| 5,405| 6,219
30- 5,644| 6,219| 6,071
35- 5,644| 5,627| 5,200
40- 4,991| 4,294| 3,635
45- 3,698| 3,375| 3,635
50- 3,698| 3,548| 3,635
55- 3,698| 3,790| 3,461
60- 3,270| 3,288| 3,100
65- 2,767| 3,115| 2,381
70- 2,798| 2,510| 2,381
75- 2,700| 2,325| 2,381
80- 2,474| 2,381| 2,325

And here's the same table using Horsepower. Horsepower is constant because gearing is taken into account that manipulates RPM, so those big torque numbers still equate out in horsepower:
Horsepower
MPH/Ford 6.7/Ford 6.2/Ecoboost 3.5
10- 245| 93| 125
15- 315| 129| 180
20- 385| 194| 240
25- 340| 261| 300
30- 315| 360| 340
35- 385| 380| 350
40- 371| 331| 246
45- 350| 297| 310
50- 350| 332| 340
55- 385| 396| 362
60- 371| 380| 350
65- 350| 377| 288
70- 385| 331| 320
75- 380| 331| 330
80- 371| 360| 351

I think the fact that diesels now make just about the same horsepower as the gassers is playing into why the diesel is now maintaining so much of an advantage through the gearing. This is crazy! It used to be that diesels were down about 50HP or so against the gassers.

Now in the case of the Diesel RAM half ton versus the HEMI half ton, the HEMI has quite a horsepower advantage which would play out and I think we would see an advantage for the gasser in hauling in that case. Where as in the practice case above, the ford diesel was within 30hp of the gasser. Torque curve and horsepower curve played a large part in this as well. Notice how nicely the ecoboost surpasses the 6.2L in a few areas.

Doing this excercise was a real eye opener for me! Also, here's how the gearing worked out for these vehicles at the calculated torque and horsepower values:
Gearing
MPH/Ford 6.7/Ford 6.2/Ecoboost 3.5
10- 1| 1| 1|
15- 1| 1| 1|
20- 1| 1| 1|
25- 1| 1| 1|
30- 2| 1| 1|
35- 2| 1| 1|
40- 2| 1| 2|
45- 3| 2| 2|
50- 3| 2| 2|
55- 3| 2| 2|
60- 3| 2| 2|
65- 3| 2| 3|
70- 4| 2| 3|
75- 4| 3| 3|
80- 4| 3| 3|

If anybody has better numbers for the new 6.7 and 6.2 with the most current torque curves, I can improve the accuracy of this analysis to some degree. Still interesting to look at!

Also, another interesting thing is that the gasser is holding 2nd gear at 70mph. However, due to the limitations of Google docs, I can't work up a higher redline RPM than 6,000rpm and I had to start at 1,750rpm on this analysis. If I had more cells to work with, I could build a more complete model. But this has been really fun to compare. Now if only I could get data on a horsepower curve of the 5.7 HEMI and the upcoming 3.0 Ecodiesel. Then I can just copy and paste all my stuff and build a nice comparison. Would also need ratios for gears and axle for both trucks. Too bad most manufacturers don't post horsepower charts anymore.