More work can be done? 325@2900=588ft/lb tq. and 325@3300=518tq, right? Am I missing something? Which is more powerful? There is a law or whatever to explain this?


Also the example of the auto reaching 2000rpm and 560ft/lb of torque on startup is suspect. Remember the example illustrated by the ford smoking its tires? That was done by powerbraking, allowing the engine to achieve much higher torque levels than at off idle. That allows the truck to break loose the tires at brake release, however not recommended by truckmakers probably and probably not helpful for powertrain reliablity. Also powerbreaking would not be needed if maximum torque was reached as soon as I been reading. 2000 rpms immediately does not mean 560ft/pds tq. Unless you prespool the turbo.
About whether the dodge can pull its weight uphill. That is not what I said. I said that it could LAUNCH uphill, dad, pulling 13,500lbs with zero throttle. Something that you said it could not do in post 502. Your quote "I KNOW for a fact that you CANNOT get the whole torque engaged, it is an impossibility." I know you can read so I will leave it at that, but yes it can, near 100% efficiency of clutch if not 100%. If you go back and read the article it said they did it by side stepping the clutch. I assume that to mean they moved their foot sideways until the foot slipped off the clutch.

I mean the funny thing is that the dodge can do what you say is an impossibility because of its low end torque and the ford cannot possibly develop 560 ft/lb of torque at or near off idle. My observation is that the dodge has more low end than you give it credit for and the ford has less. Is there something wrong with that observation?

 

At 2900 rpm the cummins is making 325hp. At 2900 rpm the PSD is making about 300 hp.

Your comparing a juice to an ez. Not the same thing. An ez is a mild fueling box. Check out this torque curve. http://www.tstproducts.com/PMCRDyno.htm
This is with just a clutch and a pusher pump. Makes a little bit more torque than that juiced up V.

Hate to shoot you down on this one but its not because of more torque. Even though it has it. Its because cummins has software to let you do zero throttle launches. It is more difficult that you think to program a truck to start off with zero throttle under load. But it is just programming.
My only problem with this statement is that the powerstroke does not make more hp than a uprated cummins. V or no. Its not because of the configuration though. Its because of the fuel systems and the cummins has a more durable bottom end. Making a high hp cummins is cheaper than making a high hp 7.3. The 6.0 and hpcr cummins are pretty new but there have been some hpcr's at the dyno events already around 600hp. Seems like an early lead with new technology.

 

I know this was not directed to me but the higher rpm arguement is meaningless with respect to this topic. With gearing, both vehicles can go from 0 to whatever, except in this case the ford has a governor to prohibit it from reaching the speed of the dodge. Not a plus for either in my case, My truck will never see either of those speeds.

What it does mean is that the ford needs 3300 reach its horsepower potential, the dodge 2900.............and the cat c7 2400.

 

Im gonna guess that the cat will last longer.

 

LH: Two degrees in engineering ... U.S. Naval Academy and Old Dominion University, both ABET accredited. I work as a Manager in the System Engineering field, aerospace related work. I have 5 years teaching experience at a university ... including teaching technology to non-engineers. Thus, I try to relate things by analogy or in laymans terms alot. Just for you:

• Speed = velocity (synonyms)
• force applied over a distance is work (ft-lbs)
• power is how fast you can deliver work (ft-lbs/second)

For dispenser, cause he seems a little slower:

• Work is energy ... but torque is force (though same units)
• Work in the world of spinning stuff is torque times radians, which is unitless. Then you have an outcome still in ft-lbs, but now it is work. (Hint: the PSD ... though slightly lower torque ... has many more radians ... and thus MORE work all together)

Dispenser says: More work can be done? 325@2900=588ft/lb tq. and 325@3300=518tq, right?
IRONMAN: Yep. Guess what, Dispenser. 518 ft-lbs of torque at 3300 rpm produces more work, knucklehead. If you need an engineer to help you w/ the math, re-post and I'll do the math for you. You can skip the whole radian garbage, and do a quickie estimate by multiplying the rpm x torque. See which number is higher (Answer: PSD)

Dispenser says: Also the example of the auto reaching 2000rpm and 560ft/lb of torque on startup is suspect.
IRONMAN: Dispenser. You're suspect. I personally took my PSD out today and did that.

Dispenser says: I mean the funny thing is that the dodge can do what you say is an impossibility because of its low end torque and the ford cannot possibly develop 560 ft/lb of torque at or near off idle. My observation is that the dodge has more low end than you give it credit for and the ford has less.
IRONMAN: Dispenser. You're the funny thing. Nobody said the PSD produces 560 ft-lbs at or near idle. HELLO ... McFLY! I'm starting to worry about you. Again, for the umpteenth time (READ SLOWLY) ... the PSD has an automatic transmission. You push the gas pedal, and it revs up to 2000 rpm. It is connected purely by fluid to the transmission, so it's okay ... it can do that. The fluid is flung outwardly (along a continuously changing vector, Heretic) and through a "torque converter". That fluid comes out at a high speed and velocity, and it starts hitting against the transmission fluid-receiver-thingie. The torque (560 ft-lbs) is multiplied by about two-and-a-half times ... MINUS ... 25% inefficiency for Heretic's sake ... and gives you a net gain of 1.86 times in torque. Then through first gear. Then through the rear axle. Summary: the 560 ft-lbs is coming from an engine revved up to 2000 rpm ... which is exactly what the PSD does. Even Heretic will agree to that.

Heretic. Maybe you can start a PSD vs. CAT thread?

 

You're the one who replied to my comment remember?

DieselDonor: You didn't address my thought though. Judging by the torque curves provided at www.edgeproductsinc.com at all rpms lower than 3000 the Dodge Cummins puts more torque to the wheel than the Ford PSD. Any information to dispute this or is it an unfair evaluation?

Ironman: See the V-8 has better modifying potential

DieselDonor: Notice how your not addressing my statement that the Cummins lays down more torque at all times under 2850 rpm? Therefore it can start off towing faster and tow heavier.

Ironman: Your cartoon torque curve is invalid.

DieselDonor: Well of course I knew it would be invalid for some reason or another but I thought you would think up something better than "they use a colored line so its false". Just so were very clear here I'm talking about the STOCK line on those graphs... you know the very bottom line, the dark blue one, the one before they put any mods on and they dynoed it stock.

 

This is weird. I thought they both did the SAME amount of work. Just at different rpms. At the risk of sounding redundant the cummins makes more hp at every rpm below 2900.

The 10000 vs 5000 rpm example doesnt really work. Through gearing they will have nearly identical torque at the wheel. The 10000 will need double the multiplication to put down as much torque. Not that it would need to at lower speeds. As you can tell though it can really hold a gear. On the top end though they will have the same torque at the wheel. Because the 5000 can use a taller gear and makes double the torque. This is when the resistance overcomes the applied torque.

I must remind you that the fastest truck in the world is a low revving inline 6.

 

I'm no engineer so I can't compete. What kind of a dyno did you use to get 560? It went to 560 in how long? according to your figures almost immediately from off idle?
How bad did it smoke the tires?
Wait, Wait, Wait......All that I am saying is that until your engine reaches 2000rpms AND AND AND the turbo increases boost to maximum, you cannot GET 560 ft/lbs of torque no matter what you say, until you get boost. I also know it takes seconds, whether it is 3 or 4 or whatever to get there. Do you have a boost gauge? The 6liters I have seen on dyno's and I have seen a few take seconds to reach full boost when locked up in top gear. I suspect yours does to. More load means quicker spoolup wouldn't it. With the engine spinning as you have said to 2000 with more available, your takeoff power will be much lower than you figure unless you powerbrake, no?
As an example my 2000 cummins in first gear will not even reach maximum boost by the time I need to shift hence I doubt that I could reach maximum torque as I slide by 1800 rpm. These motors do need maximum or close to maximum boost don't they? What am I missing?
And sorry, I can't resist......why do you like the c7 if it only goes to 2400, in fact is configured mostly like a cummins?

 

Turbos do muddle the results. Thats one more thing we are not accounting for. If there is zero boost when you flash the converter. Which is how its generally done. How much torque is being multiplied. Definitely not peak torque. Couldnt be. We have assumed in all are figures full throttle with full boost. This is not the way it actually works. Game point for dspencer.

In other words. If max multiplication only lasts a few tenths of a second. The engine is not putting out full power while its multiplying. Further hobbling the acclaimed auto. A manual will not suffer the same because it is not dependent on a flash or a stall or multiplication. It also will be producing lower power than we assumed until the engine gets a good load on it but the multiplication is always available and not a flash in the pan like a TC. Clutch engagement torque for the 6.0 is 340 I think. The flash number would be closer to that than 560. I think this 340 number is how much torque the engine could produce without the benifit of a turbocharger. Am I mistaken?

 

Lets lay this out because it was my example. This was a few months after I built a torque monster 429, peak torque around 3000rpm and hp around 4000rpm. I don't remember the exact numbers, it was 4 years ago and I blew the engine up 2 weeks later.

I was getting ready for the drag strip the comming weekend and was trying to find the best way to hook up the truck. 4.10 rear gears, c6 tranny, first is only 2.46-1 on this tranny, TCI converter rated at about 2200 but with my engine it was more like 2800. The only thing I wish I had was a dyno sheet for that engine.

First attempt, power brake method, I could take the it up to about 1600-1800 before i over came the brakes. As soon as I lift left the brake pedal, gas pedal goes down, engine instantally hits almost 3000 grand and the tires break loose, I don't move a foot.

Round 2, at idle, mash the throttle. Same results, tach hits 3000 grand and tires break loose, I don't move a foot. This is happens in a instant.

Lets break down what happened here. In the first attempt the engine and tranny are already working I have have lost some of my torque multiplication but not all. When I lift the brake, floor the throttle I'm at max torque and still have some multiplication left, so yes I'm at max torque+. The second attempt is even worse, peak torque with full multiplication.

So what the Jarhead is saying is not only possible but highly likely.

For LH. I did say the Dodge could pull more but I may have confused myself. Looking at the F250 to the Ram 2500 they both have the same 20000 GVCW. But the Ram is rated to pull 12650 compare to 12500. Well this one was easy, the Ford weighs more. Compare the F350 and 3500 its got to be something different, brakes maybe? The F350 can tow 13400 and the Ram 16500.

 

Smells like bull to me. If some company as simple as a civilian auto manufacturer was able to develope such a transmition, or any frictionless drive unit, they would easily be awarded the nobel prize for the next 30 years. The torqshift transmition was designed with the thought in mind to "reduce" torque loss in order to bring it more up to par(as far as torque loss) in comparison to a manual transmition. However, the Allison has already accomplished similar goals years prior. And with dodge's new automatic due out, they all are on the same playing field with a very small margin of difference.

In the end, all that really matters is how much torque is being applied to the axleshaft at a given wheel speed (this is basically what is known as horsepower, a derivative of torque). Everything in between is meaningless. Who cares if the engine spins 1000 or 1500rpm to achieve the same thing?

All of these rigs have more than enough gearing and initial engine torque to get off the line easy enough, it is more of a matter of mid range power that you are using at speeds while towing to keep your speed up.

 

tmyers
did you have a turbo. The difference is that a turbo takes seconds to spool, at least that has been my observation. Max torque in any of the big three diesels takes seconds, all in which the input shaft starts turning and the multiplication starts going down. My example was the ford pictures of it smoking its tires can only be done (assuming good traction)when it has been powerbraked, allowing time for the turbo to spool. Even when a transmission allows the rpms, there is a time needed for the exhaust of the diesel to charge the air allowing the power.

 

Lets leave the turbo out of this, it really makes no difference to the subject at hand. If we assume the the turbos spool up at roughly the same rate the only thing that changes is the available torque. If you want to talk about it though we can. In this case the auto wins hands down, in fact I'll bet that even the Dodge auto will make boost quicker than the manual.

 

Well I was exaggerating a bit on the Torqshift having no drivetrain losses. Being sarcastic for Ironmans sake; feeding into his dreamworld where Ford PSD's are superior in every conceivable way. I have noticed that they have been programming autos of the same make and model to match the manual. In which case the auto prevails because you would have to shift the manual perfect every time in order to match it.

 

Not to change the subject but a company named Torvec has just been issued a patent for a continuously variable transmission. They have never sold anything but there stock has gone up. They claim to be working on one to try to sell to chevy in their suvs. The are claiming to be much more efficient than the auto.