2025 Ram trucks

[nisaacs]

One should be very careful buying from a company who changes/updates their engine every 2 to 3 years to address complaints and issues.

Funny thing is, they didn't update the worst issue of all which has been the roller rocker valvetrain they switched to a few years ago. And they went back to a "revised" version of the problematic CP4 fuel pump. That's not going to sit well with loyalists. OH, and the new engine has OTA update capability....which essentially means they can spy on you and verify any time you tune/modify the engine.

This is an absolute no-go for me. I'll keep my old Powerstroke forever and if it dies I'll buy an old Cummins or another old Powerstroke.

Hot shot trucker I know. '22 Ram 5500.

 

[Engineer42]

Hot shot trucker I know. '22 Ram 5500.


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I hope he's paying attention for another pic in about 3k miles. He's getting his moneys worth out of it I'd say.

 

[Hay Dude]

Looks like I have a long way to go on my Cummins.
A tribute to the longevity of powerful, but low revving straight six engines.

 

[Hay Dude]

Hot shot trucker I know. '22 Ram 5500.


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Averaging 58MPH.
That’s movin’…..

Range 1030 miles.
If he has a 50 gallon tank like me, that means 20MPG.

 

[nisaacs]

Averaging 58MPH.
That’s movin’…..

Range 1030 miles.
If he has a 50 gallon tank like me, that means 20MPG.

He has the 52+22 gallon tanks. He delivers Gatormade trailers, so he is empty about 1/2 the time. Kinda like RV transporters.

On 11/06/21 his '18 Ram 4500 had this: "Truck is at 398,065 miles and 6,953 drive hours."

 

[WinterDeere]

Anyone following the new '25 Rams? I like what I see. Some changes noted.
...
3.42 gears only
...

I'll have to admit to skipping a few of the 7 pages of posts, but say it ain't so??? When I bought mine, standard gears were 3.23, 3.55, and 3.92. Of course I ordered the 3.92.

Even with the ZF 8HP trans, the 3.23's and 3.55's feel almost like a CVT, like driving a sack of wet rice.

As tranny gear count climbs, and lower ratios are available right at the tailstock, suppose there's less and less justification for these high-ratio rears. But I still hate the way low-ratio rears feel, no kick in the pants when the tranny shifts, to put that smile on the face of your inner hot-rodder.

 

[dieselscout80]

Aren’t the Fords and GM diesels still V8’s with turbos? Unless your talking 18 wheelers I’d think they make up a significant amount if the market.

Yes they are I was merely saying that straight six engines are typically long strokes and produce their torque at lower RPMs.

Any engine with a longer stroke tends to produce more torque than a shorter stroke engine.

 

[Blue Mule]

Hot shot trucker I know. '22 Ram 5500.


View attachment 2221809

Hotshot trucker with the 6.7L Ford diesel engine finally had to get a rebuild just prior to 1,000,000 and it wasn't because of the internals. Something else let go. You just don't see this with Cummins 6.7L engines anymore.

 

[Renze]

Yes they are I was merely saying that straight six engines are typically long strokes and produce their torque at lower RPMs.

Any engine with a longer stroke tends to produce more torque than a shorter stroke engine.

True.

Much of the idea in North American minds about inline six having more torque and being more durable than V8, comes from the fact that North American manufacturers offered a heavy duty undersquare inline six next to an economy alternative oversquare V8 for the buyers who used to buy a gas engine in heavy trucks, often with higher rpm no turbo and no cylinder sleeves.

Cummins V903 vs NT855
V504 vs 6CT8.3
Cat 3208 vs 3406

Then there were the heavy duty V engines like Cat 3408 and Cummins V1810 about which nobody ever complained about torque or longevity, because they werent an oversquare economy design..

Krupp in Germany replaced their 2 stroke engines with a license built Cummins V8. They never recovered from that and disappeared from the market.

The short stroke higher rpm V engine trend that America saw in the early 60s never caught in Europe because the heavy truck market was diesel from the start, there were no Hall-Scott or 427 Fords in trucks to be replaced with a cheaper diesel engine option... Turbocharged long strokes started in the mid 50s in Sweden and Holland.

 

[DarkBlack]

Any engine with a longer stroke tends to produce more torque than a shorter stroke engine.

It all depends….
Depending on what other aspects of the design are kept constant.
You could conversely claim, a larger bore tends to produce more torque than a smaller bore, assuming the stroke is kept the same.

There’s no technical reason a V8 can’t have as long a stroke as a straight 6, or that a straight 6 can’t have as large a bore as a v8.
In fact the outgoing 5.7l hemi has a slightly longer stroke than the new hurricane straight 6.

 

[dieselscout80]

Correct it’s not a rule but rather an example.

 

[WinterDeere]

It all depends….
Depending on what other aspects of the design are kept constant.
You could conversely claim, a larger bore tends to produce more torque than a smaller bore, assuming the stroke is kept the same.

True. But it's also true that the inline 6's tend to be built with the longer stroke/bore ratio, and that for the same CID, longer stroke favors higher torque. What you're discussing, keeping the same stroke and increasing bore, is increasing displacement.

There’s no technical reason a V8 can’t have as long a stroke as a straight 6, or that a straight 6 can’t have as large a bore as a v8.

Seeing as how the convention has developed to put the longer stroke/bore ratio in the inline 6's, versus the v8's, I actually suspect there is some technical reason for it. Engineers don't operate on whims, there must be good reasons for these trends being so prevalent. As to whether those reasons are "technical", might just depend on how broadly you define that word.

 

[ericm979]

I think with modern turbo engines, tuning has a greater effect on low rpm power (what most people mean by "torque") than bore and stroke.

I was curious so I dug up the bore/stroke numbers for the three HD pickup engines, and their power curves:

Bore x Stroke:

Cummins 6.7: 107x124

Powerstroke: 99x108

Duramax: 103x99

The mildly undersquare Ford wins both for peak hp and torque and low rpm hp and torque, the more undersquare Cummins comes in last, with the mildly oversquare GM in the middle. The Cummins signs off the soonest though at an rpm that's well past the power peak for any of the engines.

 

[Hay Dude]

The other great thing about in-line six configurations is they are cheaper to build/buy & maintain.
They get better fuel economy
Their crankshaft is stronger because its supported by more bearings

Thats why in line sixes are most prevalent in heavy tractors and OTR trucks.

 

[Hay Dude]

I think with modern turbo engines, tuning has a greater effect on low rpm power (what most people mean by "torque") than bore and stroke.

I was curious so I dug up the bore/stroke numbers for the three HD pickup engines, and their power curves:

Bore x Stroke:

Cummins 6.7: 107x124

Powerstroke: 99x108

Duramax: 103x99

The mildly undersquare Ford wins both for peak hp and torque and low rpm hp and torque, the more undersquare Cummins comes in last, with the mildly oversquare GM in the middle. The Cummins signs off the soonest though at an rpm that's well past the power peak for any of the engines.

Interesting/suspicious on your charts they didn’t use the high output (HO) Cummins in the comparison.
It made 400HP and 1075 TQ.
Must be a chart bought & paid for by GM & Ford….lol

 

[ericm979]

Interesting/suspicious on your charts they didn’t use the high output (HO) Cummins in the comparison.

They also did not include the high output Ford. Or the '23 on higher output Duramax.

I'm not trying to put down any brand, just posting data about the actual low rpm power of the different engine configurations and bore/stoke ratios. Clearly all the engines make more than enough power for their intended use.

 

[Hay Dude]

They also did not include the high output Ford. Or the '23 on higher output Duramax.

I'm not trying to put down any brand, just posting data about the actual low rpm power of the different engine configurations and bore/stoke ratios. Clearly all the engines make more than enough power for their intended use.

‘23 Dmax is 2 years newer than the other 2. Best way to compare things is compare same years.
I’d compare all 2021’s, all 2022’s, etc.

Also interesting to point out although having the lowest HP rating, the Ram had the highest towing capacity on most models.
In 2020, the Ram I bought had a GCWR of 43,000. Comparable F-550 and GM-5500 were lower with a GCWR of only 40,000

 

[Renze]

True. But it's also true that the inline 6's tend to be built with the longer stroke/bore ratio, and that for the same CID, longer stroke favors higher torque. What you're discussing, keeping the same stroke and increasing bore, is increasing displacement.

Most important reason that the common idea is that long stroke means more low end torque, is because in naturally aspirated, 2 valves per cylinder engines, the valve diameter limits high rpm breathing on an undersquare engine vs an equal capacity oversquare engine, just because you can put larger diameter valves in a head atop a larger bore engine. There might be other factors involved, but i am a well informed tech enthusiast, not an engine guru.

Either way, i think the mediocre V8 diesels at Cummins and Cat, contributed to the popularity of the Cummins inline 6 in the Ram...

Seeing as how the convention has developed to put the longer stroke/bore ratio in the inline 6's, versus the v8's, I actually suspect there is some technical reason for it. Engineers don't operate on whims, there must be good reasons for these trends being so prevalent. As to whether those reasons are "technical", might just depend on how broadly you define that word.

To get the displacement from less cylinders, you need larger pistons making it an undersquare engine, or if you dont want that, you need to upsize both bore and stroke.

The latter causes a higher piston speed at a given RPM, resulting in more wear.

If you look at the 1960s V8 diesels, they generally had a higher rpm so despite the short stroke, piston speed of a V903 was comparable to an NT855 (or whatever predecessor had 330hp turbo power at 2000rpm in the early 60s)while the V903 had the same power at 2800rpm.

The same thing still counts for pickup truck diesels: You can either add two cylinders with a shorter absolute stroke, so you can elevate its redline to gain horsepower, or you can choose an inline 6 configuration with a lower redline and less complex but beefier internals to make the hp at a slightly lower rpm.

Industrial versions of the B6.7 top out at 300hp or so, much lower than the medium duty versions used in pickups with a higher horsepower rating.

The FPT NEF67 puts out 340 engine hp in the Case Puma 340, i cant think of any tractor engine with 45hp per liter. They can do so because they dont use EGR, so the turbo can pump clean air into the engine and doesnt have to work to put 20 to 30% EGR back into the cylinders...

 

[Snobdds]

The other great thing about in-line six configurations is they are cheaper to build/buy & maintain.
They get better fuel economy
Their crankshaft is stronger because its supported by more bearings

Thats why in line sixes are most prevalent in heavy tractors and OTR trucks.

You have one mode...

 

[Snobdds]

You seem to be hung up on the turbo. Turbo chargers need RPM to produce airflow which in turn produces power. So no, the turbo has nothing to do with the fact that a diesel engine makes amazing torque just off idle. "Off idle" means what it says...just off idle, i.e. just above the point where the engine is idling. At those RPMs the turbo is doing very little.

I'm hung up because it's what makes the low end torque.

For example, on the 6.0 powerstroke, the motor that taught me. The 2003-2004 had a 10 blade compressor blade on the turbo. The 2005-2007 had a 13 blade compressor blade on the turbo. It was noticeable how much more low end torque there was on the 03-04 vs the 05-07. The flip side to that same coin was the 03-04 ran out of air once you hit 65. The 05-07 had slightly less air at the low RPM, but the air was still coming on at 65-75. I have yet to see a variable compressor wheel to a turbo. There are variable turbine side vanes that help with spooling a turbo when starting out.

Once you realized the physics at play, your understand what brings on the torque...air being forced into an engine to produce power.