Ram 2500

[thehippie]

Why is the Ram 2500 crewcab longbed with 6.7 Cummins, even though it's only 6 cylinders has more towing power than the similarly equipped Ford F250 powerstroke diesel, the same displacement at 6.7 but already at 8 cylinders??

[ShinerBock]

Here is a great article I just found about the difference between I-6 and V8 diesels.

I-6 VS V-8 Diesel

[Turtle_n_Peeps]

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Nope, torque is not power. Never has been and never will be.

To give you an example: On a bike I can put out around 225 Ft/lbs of torque. If I had a 5 foot crank I could put out more torque than a new Cummins 6.7 engine at the crank!

I can put out only about a 1/2 a HP for a short period of time.

Even though I can put out a lot of torque I would not make a good TV engine!

[goducks10]

FishOnOne wrote:

Flashman wrote:

ShinerBock wrote:

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Engine piston configuration does not determine peak torque or when it is reached. Engine displacement, bore/stroke ratio, and induction (forced or N/A) are the major things that effect torque output and curve.

Can't argue that - but notice how all the Semis are straight 6s - and torque is of prime consideration for them.

Also notice how short the power band is. Not a big deal when your running a lot of highway miles, but is a PITA when having to run around city/town speeds.

I would also suspect that crash tests standards maybe more difficult to achieve with a straight six.

Ya I hear you. I can barely get thru the intersection on a green light before it turns red with my Cummings. I usually have one of my power stroke friends tow my 5th wheel thru town and out to the freeway when we go on a trip.

[Me_Again]

FishOnOne wrote:


Also notice how short the power band is. Not a big deal when your running a lot of highway miles, but is a PITA when having to run around city/town speeds.

I would also suspect that crash tests standards maybe more difficult to achieve with a straight six.

I have owned a 1993 RAM, a 2001.5 RAM and now a 2015. I can only assume that you have never owned or driven one.

Regarding crash test, let me run into you with one and see who walks away. Chris

[ShinerBock]

FishOnOne wrote:


Also notice how short the power band is. Not a big deal when your running a lot of highway miles, but is a PITA when having to run around city/town speeds.

I would also suspect that crash tests standards maybe more difficult to achieve with a straight six.

The engine configuration does not determine the powerband either. The bore/stroke ratio does. An oversquare inline 6 can rev high just like the BMW N55 3.0L engines that redline at 7,500 rpm. Likewise an undersquare V8 can have a lower limit like the Ford 5.4L with a 5,200 rpm redline in the F150. The more undersquare an engine is the lower it's max speed and the lower it gets it's peak torque. It has nothing to do with cylinder configuration.

I don't see how an engine configuration would affect crash test ratings if it was made to break away properly in a wreck though.

[FishOnOne]

Flashman wrote:

ShinerBock wrote:

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Engine piston configuration does not determine peak torque or when it is reached. Engine displacement, bore/stroke ratio, and induction (forced or N/A) are the major things that effect torque output and curve.

Can't argue that - but notice how all the Semis are straight 6s - and torque is of prime consideration for them.

Also notice how short the power band is. Not a big deal when your running a lot of highway miles, but is a PITA when having to run around city/town speeds.

I would also suspect that crash tests standards maybe more difficult to achieve with a straight six.

[ShinerBock]

Flashman wrote:

Can't argue that - but notice how all the Semis are straight 6s - and torque is of prime consideration for them.

Semi's mainly use inline six engines due to how simple they are to work on, how simple they are to design(resize), their natural balance, and the design of a straight six favors torque due to the longer stroke that can be achieved versus a V8 design in the given space of a semi's engine bay.

It's mainly about the bore/stroke ratio as to when an engine gets it's peak torque. An oversquare engine is considered a short stroke, and has a larger bore that its piston stroke. These types of engines favor high revs to make their torque due to their short throw which more rpms creates higher horsepower numbers. An undersquare engine is considered a long stroke, and has a stroke that is longer than its bore. These types of engines make their peak torque really early with a very long throw, but do not favor high revs which means they usually do not create that much horsepower compared to a short stroke. Due to their tall and narrow design, inline six's are able to have a longer stroke that a V8 in the long and narrow engine bay of a Semi truck. The V8 would have a shorter stroke in order to fit which would mean higher rpm torque. Higher rpm torque is not ideal for towing.

On a side note the Cummins and Powerstroke 6.7L are both long stroke(undersquare) engines, but the Duramax 6.6L is a short stroke(oversquare).

[IdaD]

Flashman wrote:

ShinerBock wrote:

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Engine piston configuration does not determine peak torque or when it is reached. Engine displacement, bore/stroke ratio, and induction (forced or N/A) are the major things that effect torque output and curve.

Can't argue that - but notice how all the Semis are straight 6s - and torque is of prime consideration for them.

So is packaging and maintenance/repairs, and a straight 6 has a lot of advantages in that regard in both trucks and pickups.

[Flashman]

ShinerBock wrote:

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Engine piston configuration does not determine peak torque or when it is reached. Engine displacement, bore/stroke ratio, and induction (forced or N/A) are the major things that effect torque output and curve.

Can't argue that - but notice how all the Semis are straight 6s - and torque is of prime consideration for them.

[ShinerBock]

thehippie wrote:

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

Engine piston configuration does not determine peak torque or when it is reached. Engine displacement, bore/stroke ratio, and induction (forced or N/A) are the major things that effect torque output and curve.

[thehippie]

Turtle n Peeps wrote:
It doesn't.

Where are your numbers coming from?

i thought inline vas more torque than V.

[Grit_dog]

All you need to know is because it's a RAM! Lol

[ShinerBock]

Me Again wrote:



Still would be way over the 10K GVWR with a 17K 5th wheel. Chris

The only reason the GVWR is maxed out at 10,000 lbs on diesel 2500s is because that is the max GVWR in the Class 2b that it is in. Going by the trucks specs of it's individual parts, the GVWR should be about 11,200. The 2500 and 3500 are identical in parts besides the rear suspension. This is the same rear suspension that has a payload rating of over 3,100 lbs in the 2500 with the 6.4L. However, Ram cannot give the 2500 a 3,100 lb paylaod because that would put the GVWR of the 2500 over 11,000 lbs which is over the max 10,000 GVWR limit of Class 2B that it is in and put in in Class 3 where the 3500s are.

Although, I can go down to the tax registration office here in Texas and pay double as much to register my truck as a class 3 truck(since it's axles allow it), and not a cop in Texas can stop me from being over 10,000 lbs GVWR. The class system is for DOT and EPA regulations and tax registration , nothing more.

[spoon059]

Me Again wrote:
That 2500 4x4 with a 10,000 GVWR and 6,000 RGAWR will be hard pressed to tow a 17K 5th wheel without being overloaded by pin weight. Not even an aluminum Andersen hitch will fix that. Base weight of rear axle is 2948 then add a hitch/bed stuff and 3400 pounds of pin weight and you exceeded both RGAWR and GVWR.

Chris

Chris, just an FYI, the diesel crew cab 4x4 2500 has a rear axle rating of 6500 lbs. You are 100% right that the Ram 2500 AND the Ford F250 will both be over rear axle rating on a 10K lbs truck before they get 16 or 17K lbs behind them. The question was about tow ratings, someone asked where the OP got his numbers from, I simply posted the numbers.

I am well underneath my numbers, as I bumper pull an 8500 lbs trailer with about 1100 lbs of tongue weight. I have about 1300 lbs of payload left over for the kids and any gear we bring in the bed. When it comes time to get a 5th wheel, I will be getting a 1 ton for sure.

That being said, one of the guys that we camp with at the lake has a 2014 Ram 2500 with the coil rear suspension. He tows a 42' fifth wheel, has a wife and 2 kids and a 150 lbs St Bernard. He is WELL over his (arbitrary) 10K lbs GVWR, but under his axle weights. The lake is in the mountains of western PA and he gets there and home safely every time. Not advocating it, just pointing out that the truck is perfectly capable of handling those numbers.

[IdaD]

Me Again wrote:

IdaD wrote:

Me Again wrote:

IdaD wrote:

RAWR is actually 6500 on most of them (18" or 20" wheels). We all know the story on the diesel 3/4 ton GVWR/payload deal.

http://www.ramtrucks.com/assets/towing_guide/pdf/2016_ram_2500_towing_charts.pdf

Very few trucks are sold with 17" wheels, and those are the only ones with a 6000 lb RAWR. The models with 18" or 20" wheels have a 6500 lb RAWR.

Still would be way over the 10K GVWR with a 17K 5th wheel. Chris

Yeah if you have a fifth wheel with 20% pin weight. A 17k lb trailer with a 10% tongue weight would be under the 1800 lb max for the rear hitch, though.

I wouldn't personally lose much sleep about being a bit over the GVWR on a diesel 3/4 ton as long as I stayed in my axle/tire/wheel ratings, but that's just me.