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Dnewton.

The angle should be 4 degrees. ArcTAN of the rise over the run, or in this case ATAN(0.07/1). I understand why you got what you got. The math itself was correct.
What I stated about the Normal force is the definition of Normal Force, not my definition. Does not affect your spreadsheet however.
As I say, I agree with your general premise. Your spreadsheet shows the general idea of it well and shows the effect relative truck to truck as well.
Absolutely agree, all three trucks are so close that any change in factors could possibly shift the win up the hill. To be honest, I don’t believe that most on here would really disagree. I don’t however see the need to belittle others because they are not as passionate about the math as you are. I do not believe that a lack of interest in such things makes one stupid.
 

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I believe elsewhere someone defined the Power Band (or usable RPM band) as the RPM band between the peak Torque and the peak HP.

I propose that it is broader than this.
There is a good deal of usable power above the point peak power. Using power curves from past engines I have estimated the power produced by these engines at values above 2800 RPM. It is clear that the usable RPM extends for several hundred RPM beyond the peak HP.
For values between the peak torque and peak HP, I calculated Torque/HP using the assumptions used by Dnewton in the first sheet of his 1st spreadsheet (assumptions that I am comfortable with).

Using these admittedly broad assumptions, I found:
The Ford has a significant power advantage at 45 MPH.
By 50 MPH the Duramax has a decent advantage.
At 55 MPH the Ford is creeping ahead.
At 60 MPH the Ford has a substantial advantage over the Duramax.
The Duramax begins to produce more power by 65 MPH.

I think this also demonstrates the advantage that additional transmission speeds could bring once these trucks start pulling really heavy loads.

Looking at this, there is a conceivable load where the Ford could best the Duramax (although it also hints that the Ford should have done better than seen in the IKE test).

Also, it begs the question; how in the world did the Cummins beat the Ford (or for that matter do as well as it did against the GM)? Darn impressive. And best fuel economy to boot.

It’s great to see real world testing, because, as has been demonstrated, it is difficult to know how a truck will perform by looking only at the numbers.

About my assumptions:
For the GM, I looked at the shape of the LML powerband and applied it to the L5P. I think there is a potential for a great deal of error here as the L5P is obviously tuned much differently than the LML and, as we all know, a completely new engine.
Source of the LML power curve: 6.6L Duramax LML Specs & Information

The Ford was taken from the 2015-2016 power curve, which I suspect is very similar to the 2017.
Source of power curve: 6.7L Power Stroke Diesel Specs & Info

The newest power curve I could find for the Ram was 2011, which is likely much different, so I did not even bother.
 

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Julius Sumner Miller could clear all this up and have the last word if he were still living:rolleyes:
 

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Sparky -
I was able to find the formula for the grade; it's as you state. The error I made does not greatly affect the final number, however, because when the angle is small (below 10 deg) the difference between the real value (calculated as arctan) versus my estimate by algebra, then applied via the trig of the resultant, didn't really shift numbers much. However, to be as accurate as possible, I corrected the formula.

I would agree there is power above the HP peak, but as many times as I've watched the videos, I don't see that happening. Teh ECMs will upshift when at or over HP peak, and will downshift when at or below TQ peak. That's how they make the most thrust forward; between these two points. I see no evidence that the engines are running past HP peak. These don't respond like a gasser engine. Reving them past HP peak won't gain much if anything, because TQ falls off dramatically after peak HP. And it is torque that creates thrust. In the videos, the ECMs are managing the thrust between the low and high of the "powerband" (peak to peak). So while I don't disagree with your concept, I do disagree that it manifests this way in reality. Power may be available past HP peak, but it's not how the ECMS manage the system. Diesels gain torque as rpms fall, as long as they are between peaks. That's the advantage of the diesel process.

As for the normal and load forces, I also updated those. The "normal" force would be the cos of the angle, whereas the pull load force would be the sin of the angle. The normal force is calculated into the CoRR (rolling resistance) and the pull load is what is applied to the tongue of the hitch in pull force.

Additionally, I added two more columns; you can now see how thrust affects vehicle speed directly. There is a max thrust (at bottom of powerband), a mid-value average, and a thrust at peak HP. This way, you can see how close or far away a vehicle is from holding a relative wheel speed. What is important to see here is that as the "net thrust" changes, it will help understand how close to the min or max speed one is. If there is a large amount of excess thrust available, it's likely to hold the veh speed towards the upper end of the gear range. If the thrust drops off, but stays in a gear, it will tend to the lower end of the speed range. Remember - as rpms drop, torque goes up, so they tend to hold lower rpm actually better.

I also updated the spreadsheet again for convenience; it now lets you input the trailer weight and truck weight and grade on the first tab, and then copies over to tab 2 for calculations.

One has to realize that the grade changes in the test uphill. It's probably 5% at start, most of it is 6%, and then peaks at 7% near the "top" (about the last mile or so). I say this because I went to the USGS topo map links and viewed the relative elevation changes. And this is critical here, because as the grade changes, so will the resultant loads on the drivetrain. As run in the video, the Ford was able to attain 4th, but had to drop to 3rd. GM and Ram ran the bulk in third, and I think the GM probably dropped to 2nd near the end. Not sure what the Ram experienced.

Use the spreadsheet tool linked here (version 3) and play with the grades and loads. You can see that, as run, the GM won because the Ford had to downshift, and got outpaced. But if the load drops to 20,000, with all other factors the same, the Ford would have probably tied. The Ford does make more average power and just a hair more avg torque than the GM, and way more than the Ram. Yet the Ram essentially tied the Ford, because it was still able to run in 3rd for most, if not all, of the trip.

If they IKE was run at 20,000 pounds trailer weight, the Ford and GM would have probably tied. If the Ford had 3.55 gears rather than 4.10, it may have won or almost certainly tied the GM. Even if you up the trailer load to 25,000 (ignoring GM tow limit), the Ford would probably win because it'll hold 3rd, where the Ram and GM would drop to 2nd gear once the 7% grade is reached.

Even if you alter other inputs such as CoRR or wind speed, it still shows a relationship that does not alter. If you change the CoRR, affecting resultant load, it only means that a DIFFERENT trailer load would still select a winner and loser.

I'm fine with the fact that GM won this. But it's biased inadvertently and unwittingly. We could tailor each load and come up with a winner/loser.

All three trucks are great movers of big loads. As equipped, the Ford and Ram can move way more; but they sacrifice a bit of speed for that ability and will occasionally lose (or win) a race due to gearing differences. If you don't needs that capacity, then fine. But if you do, it is there where the GM does not offer such. If GM did offer a 4.10 or 4.30, it would certainly pull more, but change things all over again.



What is totally apparent (to those with objective eyes) is that I was right about this all along. I certainly realize that some are going to call this a self-fulfilling prophesy. Yes - I needed a few clarifications and help; I don't mind help when it's directed and specific and accurate. Unfortunately, many of you threw out some really useless, wild-ass stabs and frankly that's not helpful. But once the dust settles, the engineering science is not only viable, but very probable. Any tiny nuance can be offset by another nuance assumption. I cannot promise that we can calculate the EXACT load that would cause these to change, but we can certainly predict a range of load that will alter the winner. I've said this all along; this load is biased to the GM. This IKE system they use will always favor one brand over another, simply due to dumb luck. This certainly shows that as the load changes, the response of each truck will vary and place it either ahead or behind the others. I realize no one wants to hear this, but this spreadsheet shows beyond any doubt that it is not only possible that I'm right, but probable that I'm right.
Change the load? Change the winner!


.
 

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My math teacher use to tell me " Math is the only true science, everything else is theory.
You can make all the charts and spreadsheets you want but in the end your making a guess. I'm not sure why you are trying to discredit the testing or want to try to prove the test is biased towards the GM so much, even if you say that's not your objective it looks like it is.
Its one test, it's not the end all of tests, just like the other thread with the Dino runs, the Dino doesn't tell you the real world usage, if it did the GM wouldn't have been able to pull off the win.
 
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The spreadsheet clearly shows how different loads will affect real performance. I already agree that I cannot predict the EXACT weights, but I certainly can show ranges that will affect real performance results. And the dyno tests clearly show it wasn't the engine that got them there. Of the three, it was the weakest. Or, are you in denial of that, too?

The IKE win was valid. And if you own an RV that weighs between 22,000-24,000 pounds you can take this test to the bank. The rest of us see reality for what it is; it was dumb luck that TFL chose a weight that benefited the GM. In no way am I saying the IKE result isn't real. It's just not repeatable at all loads. Each brand will win/lose depending upon which load places them somewhere in the spreadsheet range.

Oh, but Dave, it's about the boost ....
Oh, but Dave, it's about the torque converter ....
Oh, but Dave, it's about the circumference of a circle being the component of torque ...
Oh, but Dave, it's about the top HP rating ...
Said all those in denial.

The GM won, but it cannot repeat that win all all loads.
Change the load; change the winner.
 

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... And the dyno tests clearly show it wasn't the engine that got them there. Of the three, it was the weakest. Or, are you in denial of that, too?

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Which really just means that the spreadsheet doesn't really tell us anything about which is the fastest with a load, only theory.
 

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I am comfortable with my arrogance.
I will leave you all to your ignorance.
 

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I am comfortable with my arrogance.
I will leave you all to your ignorance.
Ignorance is disguised as arrogance to the untrained eye.
 

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Dnewton3,

TFT just posted dyno numbers on you tube and the Chevy came out very weak. If possible, plug in these corrected numbers into your spread sheet and see if they match the results or the expected results. Based on other dyno runs that I have seen for the new L5P, I think the truck provided for testing was sub par.
There is still one other important item that hasn't been discussed in this thread. All of the trucks ECM's will pull fuel when egt's get too hot. The ram air on the Chevy should allow cooler intake air temps and less hp loss. This same effect could drastically reduce available hp in high ambient temps with the same test. We assume that hp and torque remain the same through out the test, but in theory, the actual numbers could vary greatly. Even how long the fan clutch remains on will have a huge effect. These are variables that will be hard to account for, but based on the words of the Duramax design engineer, the hood scoop is designed not to increase power but to be able to maintain power at rated levels longer.
I have towed heavy loads up grades equal to or greater that the Ike with my 02, with a dyno proven 540 rwhp, I can guarantee everyone that I can't use all the power all the time. I have to back out to keep egt's in check, after a certain period of time I have to back out again due to coolant temps and after coolant temps climb, so do tranny temps. I do these things with common sense, the new trucks do these things with ecm calibrations.
My theory is that if you plug in the real world dyno numbers, Chevy would have lost the Ike no matter how the numbers were plugged in. The only explanation would be that Ford and Dodge ecms pulled fuel and the power output was dropped. You are good at running the numbers, plug in these numbers and see if your calculations can match the results. For another variable, if we had a GM that put down better numbers from the start as I have seen on other dyno runs, and if the cold air intake has the desired effect, gm could have won the test by a much wider margin.
As stated before this is bench racing at it's finest!
 
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DCamilleri,

This is a simple spreadsheet. Plug in less power and that is what you get out of it. Note this isn't at all a model of what happened on this hill. The trained already know this work isn't accomplished with a spreadsheet but with a simulation program. Spreadsheets point out where there are variables and sensitivities yet they do not model them. It is up to the trained eye\mind to infer what is being said and what isnt' being said.

Newton set out to prove you change the load you change the result but he proved it only on the spreadsheet and not on that hill because he didn't model that hill nor indeed how those trucks react on that hill. The key word here is "model" and frankly this didn't model anything other than a steady state which is hardly a "model". The words "high school" came up a lot and perhaps this would have been applicable to a high school class.

In order to achieve what you are talking about would require much more than a spreadsheet and really is what you would get out of an iterative Simulation Program.


Simple as that.
 

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I didn't even look at the spread sheet, my knee hurts so bad right now, that the pain meds are clouding my perception, but once in a while I get a clear thought. My gut feelings are GM sandbagged their numbers. The gm engineers did extensive testing on the IKE, so they already knew what the results would be.
 

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I think they just have a good combo with the duramax and Allison transmission. It's tuned to produce a wide power band, that's why they only equip it with the 3.73 gears.
 
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