psd vs cummins

FORD CRUTCHESowerband, auto vs auto, auto vs manual, engine durability, truck durability, higher quality paint and interior, more sold, more on road, have been built longer, magazine tests, engine components, _______, ______, _____,(fill in spaces)

DODGE CRUTCHESowerband, manual vs manual or any comparable test for engines(dyno, same trans. on same weight), engine durability, truck durability, magazine tests, engine components, _____, _____, _______, (fill in spaces)

However, comparing engine to engine consider what crutches are applicable and which are not.

 

Your disputing things that Ive already admitted. The torqueshift will jump to a higher initial torque value. But the standard puts more torque to the wheels over a longer period of time.
I have pointed out time and again. There will not be full multiplication at 2000 rpm. Go to a tranny shop and ask. With a flash stall. There may be for a very brief period of time until both ends catch up. So your still assuming facts that just arent true.
I dont know why your stuck on just clutch engagement. That is only the launch. I have said time and again the auto will be faster. What does it matter if for a very small period of time an auto can make more torque? Once you let off that clutch and rpms are up to 1600. It is making 14000lb ft of torque.
Its funny. You are denouncing something you have never even tried. I am advocating something Ive never even tried. I will say that I tow with diesels mostly with manuals. A good manual behind a diesel is unbeatable when you are overweight and climbing a 7% that is curvy.

The cummins has more low rpm hp. It will be more driveable. Its not really disputable. More low rpm hp gives any vehicle better driveability. Doesnt matter if its a gremlin a merthmobile a Ford PSD or a Dodge Cummins.

It becomes subjective about lauching because the cummins can launch with zero throttle. At all other rpms besides clutch engagement the manual will make more torque. Drivebility is not just the launch. You can make a manual launch anyway you want. High rpm or low rpm. Not one. You look at things like they are fixed. They are very dynamic.

 

On page 3 of this brochure. You will find the 1.86 stall torque ratio I have mentioned. It is directly below the gear ratios. You will need to magnify it to read it. http://www.fordvehicles.com/images/t...el_Brochur.pdf

This is for you ironman. Its only a 1.86 multiplier if the driveline aint turning. Then it quickly dissipates. For launch. Its good. But that torque goes away and you have a lot less than a manual who maintains it through the entire gear. Torque willing.

They also said a flash will generally ast less than half a second. So a few tenths.

Do something for me Ironman. It will not prove anything with this discussion but I am curious. Can you watch your tach when you are getting on the highway. When it goes into lockup in OD how many rpms does it drop?

 

dspencer says: First the ford f650cat combo. The same cat configuration that Marine Ironman and most ford backers bashed most of this post.
IRONMAN: You didn't read carefully enough. I posted the F650-Cat website. I think those are great trucks.

dspencer says: Next, yes the assumptions and calculations are way off but what can be expected. 560lb/tq applied directly to a drivetrain would surely break most of our trucks or at least severely lessen its longevity.
IRONMAN: What you mean is that YOUR assumption is way off ... off this planet and on another one. NEWSFLASH: The PSD generates 560 ft-lbs of torque right at about 2000 rpm. NEWSFLASH: way more than 560 ft-lbs of torque is applied to the drive train, as each gear steps down the RPM (transmission and then rear axle).

dspencer says: The auto loses most of its torque due to the inefficiencies of the auto.
IRONMAN: The TS transmission locks up in all gears. At acceleration and tow-start, there is a 1.86 stall torque ratio (as Heretic has kindly provided for us). The only time there is an inefficiency is when the transmission is unlocked ... BUT (drum roll) the multiplication factor, such as the one you see above is what is LEFT OVER AFTER the inefficiency. During that time ... the torque from the engine is multiplied by SOME NUMBER higher than one, until the rpm of the engine approaches that of the transmission ... at which point you will either shift or lock in. We are living in the year 2004. Transmission engineers have solved the problems you allude to.

dspencer: What is the power applied? I don't know but would surely take much more detailed analysis than what was offered.
IRONMAN: Every engineer always wants more detailed analysis than what they have. Managers want to know enough to make a decision. Rough-order high-level analysis can usually do a good job of estimating. Given the high BS factor I have encountered in this forum, I'd rather we make some ROM estimates, than endure the continued BS.

dspencer says: Also noted that this would be an extreme case of power braking which is not recomended for autos period.
IRONMAN: BS-alert. BS-alert. are you talking about a trans-brake or something? Explain what you are talking about, and how it is a factor in this scenario of starting from zero speed for a regular pickup towing a loaded trailer.

 

FOR HERETIC: I looked at the PSD/TS brochure. You are correct, the stall-torque-ratio is 1.86. You are correct, that is when the transmission axle is at 0 rpm, and will drop down as the transmission begins turning. Of course, our scenario is analyzing the 0 rpm point only, as we have already seen that when the PSD is wound up in it's gears, it is always out-spinning the Cummins/5600 in all combinations, as well as having greater angular (spin) acceleration.

I don't think the "flash" lasts as short as you imply, if at all. I tried some acceleration while holding my brake ... but it seems the computer KNOWS I have my foot firmly on the brake, and it won't let the engine rev high (about 1400 and it wants to stop there). I would need to have a heavy load and NO foot on the brake to be sure what it does.

Also, I'm not just stuck on clutch engagement.

I noticed this evening that in the course of normal driving, almost all the shifting jumps back and forth from about 2100 rpm to 1900 rpm. This straddles the peak of the torque curve shown in the PSD brocure. The bottom line is that the PSD is set up to maximize it's torque sweet spot, and in harder acceleration it allows the engine to get up into the low-mid 3000's ... coincidentally the peak HP of the PSD. The shifting strategy is thus brilliant.

What occurs to me, as it has from the beginning, is that the PSD is better able (due to remaining 500 to 1000 rpm above my Cummins) to always be in a state of throwing more horsepower out ... and always be in a higher rpm as noted.

I have shown before that 325 HP at 3000 rpm is always a better working engine than one whose 325 HP peaks much lower (say 1000 rpm). Reason: more speed is attainable, or ... that can be traded via the gearing for higher tow capacity. From one point of view, the PSD, by simply having 325 HP at a higher RPM is, by definition, more capable of total work than a Cummins. I think I may have already explained this previously (more area under the torque curve) but I don't know if you were with us in the early PSD/Durability discussion.

Marine Ironman

 

Higher rpm hp will provide better acceleration but not more speed. Speed is a factor of torque and gearing. You must have enough of both to overcome resistance.

You are still comparing an engine that raps out at about 2500 to one that raps out at 3300. Big difference.

It does have a good shifting strategy and good gear spacing.

It throws a lot more hp out than your cummins.

Tow capacity is not rated on where the hp is i.e. big rigs make peak hp below 2000 rpm. The truck is what dictates the capacities. You can get the 220 hp cummins or PSD in applications as big as 80,000lbs each. It has little to do with the hp. Whereas more hp will move the load faster of course.

 

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?

 

Dieselman, I'll paste those after-market curves here:



I think these are highly decorative propaganda to sell JUICE. However, notice the "levels" of improvability for the V-8 are higher? Now look at the horsepower:




Notice JUICE implies that more horsepower can be squeezed out as well. Bottom line, according to Edge Products, there is more potential capability in the V-engine. This is what I've been trying to tell you guys all along. Smaller individual piston-rod inertia, w/ shorter throws and other factors makes for higher RPM capability and overall more TQ and HP.

 

Heretic ... think for a moment. Take a deep breath. If engine-A can spin 10,000 rpm and give 500 hp .... your rear wheels are spinning about 2500 rpm.

If engine-B can provide 500 hp only up to 5000 rpm ... your rear wheels are spinning about 1250 rpm.

Now ... which one has more speed?

IRONMAN

 

Marine Ironman
1)Nomatter what you post you bragged that the ford f650 w/cat engine c7 would outpull any other light pickup. The cat is an inline 6 with (in its highest configuration according to the cat website)350hp@2400rpm and 860ft/lb @ 1600rpm. You talk it down forever and then choose it for your pulling partner???? This makes sense?
2)You list the ford giving 560ft/lb at startup while knowing the only way to make 560ft/lb with the ps is braking and fueling to reach 2000rpms. Nowhere near that at idle. Again, that is called powerbraking. Not trans brake. The only way to get 560 ft/lb at start. Only way it will happen. Right? not 560 at idle? You give the dodge idle stats while giving the ford highest possible tq. 560? Doesn't get any higher. Surely not at idle.
3)You have a paragraph about the dodge w/6sp not being able to launch without throttle? Not true. The pickuptruck.com article mentions that the dodge launched uphill zero throttle with 13,500 lb trailer.

The best one is that you say not even close. Even though most if not all tests comparing the dodge and ford give dodge the edge starting off along with all the complaints about the fords lack of low end and you turn that into numbers showing fords assumed advantage. Voodoo numbers mean voodoo output. Doesn't jive with the real world but would anyone expect them to?

Not flaming just stating facts as I see them. Again 325hp-600ft/lb tq vs 325hp-560(or570)ft/lb tq. Bigger numbers.

 

Now you are avoiding the issue again. Earlier you said you do not modify so that issue was irrelavant. Were talking stock vs. stock here as you pointed out before. This is PSD vs. Cummins, not edge product juice modified engines. Anyhow notice the STOCK torque curve. The Cummins torque starts to drop severely and matches the PSDs at about 2850 rpms and from then on the PSD holds more torque. At all rpms below that the Cummins pushes more torque to the rear wheels. Notice the Cummins also holds more rear wheel HP up until 2700 rpm when the PSD overtakes it. This is how the Cummins starts off faster towing or not as you so blatantly ignored. This is also why the Cummins can ultimately tow heavier as tmyers said... Then you said no the PSD in a 650 is still a PSD and that can tow more. Were talking F-250s and 350s here. Dodge 2500 and 3500. Not diesels that towing companies use. The only negative thing is that the Cummins can't hold power revving to 3300 rpm which isn't really a negative thing you just perceive it as one because you want to race while towing or something like that?

 

dspencer says: Marine Ironman 1) Nomatter what you post you bragged that the ford f650 w/cat engine c7 would outpull any other light pickup. The cat is an inline 6 with (in its highest configuration according to the cat website)350hp@2400rpm and 860ft/lb @ 1600rpm.
IRONMAN: Dispenser. Think for a moment, son. The maximum HP of the PSD is 325. The maximum HP of the C7 is 25 HP higher, with about 300 more ft-lbs to boot. Slap both of these on a test-sleds ... hook-em up and who do you think will win? (Answer: C7) My discussion of V versus Inline is pertaining to a pair of 6-liter engines. The C7 is a 7.2 liter engine, son.

Dispenser says: 2)You list the ford giving 560ft/lb at startup while knowing the only way to make 560ft/lb with the ps is braking and fueling to reach 2000rpms. Nowhere near that at idle. Again, that is called powerbraking. Not trans brake. The only way to get 560 ft/lb at start. Only way it will happen. Right? not 560 at idle? You give the dodge idle stats while giving the ford highest possible tq. 560? Doesn't get any higher. Surely not at idle.
IRONMAN: Dispenser. Think for a moment, son. We're talking about pulling a trailer, boy. I don't have an 10,000+lb trailer sittin around. I'm just seeing what my engine does when starting from 0 mph. I thought of holding my brake a bit to "simulate" a trailer load. The only problem is the computer KNOWS I'm holding the brake, thus ... that checkout is no good and tells me nothing. W/ a trailer I would not be mashing the brake. Well .. as far as I can tell, without the brake, at 0mph, stepping on it, the engine jumps immediately up to 2000 rpm instantaneously. Guess what ... that's THE MAX torque rpm for the engine. Now ... w/ a manual, you can rev up ... and start releasing the clutch .... but the friction plate will begin grabbing hold and lug that engine back down toward something a little higher than idle. The close to max load ... the closer to idle ... if above max load ... your engine will die. The Cummins, despite the claims of the ladies and Heretic ... don't make 600 ft-lbs down there.

Dispenser says: You have a paragraph about the dodge w/6sp not being able to launch without throttle? Not true. The pickuptruck.com article mentions that the dodge launched uphill zero throttle with 13,500 lb trailer.
IRONMAN: Dispenser. Think for a moment, son. Why wouldn't it be able to do that? Do you think I'm saying that a Dodge can pull it's rated weight up a hill?

Dispenser says: Not flaming just stating facts as I see them. Again 325hp-600ft/lb tq vs 325hp-560(or570)ft/lb tq. Bigger numbers.
IRONMAN: I say ... 325/560 at higher rpms .... is better than 325/600 at lower rpms. You left out the missing and most crucial link: RPM. The Cummins has 40 more ft-lbs of torque ... the PSD has it's "stuff" at hundres of higher RPMs. The higher RPMS wins, because more work can get done. The work can be delivered in either speed .... or tow weight. Because the PSD's max HP is 400 rpm higher ... but equal in value to the Cummins (325) ... that means if the two engines were hooked to an exactly equal gear ... the PSD would out-speed and tow more than the Cummins always.

Hope that helps.
MARINE IRONMAN

 

Dieselman: Listen son. Those Juice charts are pure fabrication. Cartoonery. Engineering is not about cartooning pictures of your theory. My ONLY response was ... hey ... they obviously think they can do more w/ the V engine. You referenced these cartoons not me ... then you start wailing on me about a stock vs. mods thing.

Listen. All you Dodgers have done nothing but create heat and smoke. It's become fairly obvious that when Dodge came out with it's big "2004.5 600 mega ft-lbs bone-cruncher engine" ... it's not really all that it's cracked up to be. They expected everyone to go " ooohhh ... Cumminssss" and line up at the cash register, and it ain't happening. Ends up ... you're much better off with a PSD/Auto.

MARINE IRONMAN

 

https://www.ford-trucks.com/forums/s...92&postcount=8

just another tidbit on auto vs. manual

 

It really sounds to me like you are not an engineer. Engineers drop words like vector, work, force and velocity. Your simple explanations are almost ver batim to what I find on the net. An engineer would not use the word speed. It is a bad descriptive word. Acceleration or velocity are better words.

This comparison misses a very simple idea. Gearing. These two engines would most definitely not be geared the same. Work is work. Both should be able to attain the same top speed regardless of where it makes its power. ASSUMING the same resistance for both vehicles. Tires size frontal area. Now acceleration is different. But as a result of gearing.