Ram HD 1000 lb-ft MPG loop

Cummins12V98 wrote:
Will be interesting when all three are tested towing 30k up and down serious grades.

Interesting it will be to see what truck is a second or two faster.

chevman

Cummins12V98 wrote:
"Remember, we're all trying to learn here, not to say who's right who's wrong..."

HMMMMM

:)

"Remember, we're all trying to learn here, not to say who's right who's wrong..."

HMMMMM

FishOnOne wrote:

Cummins12V98 wrote:
Test drove a BigHorn 2019 DRW today. Quieter than mine by a bit and maybe a bit quicker but not by much. A touch over 73k sticker.

Did you notice the new track bar bracket design?

I thought about it later, forgot to take a pic. I have seen the new design, it looks "like a Jewel" :B

ShinerBock wrote:

Still waiting? Where did I say I will show you evidence in the first place. I went back though out our conversation and didn't see a single point where I said this so i am not sure what your are seeing. However, if you want to go down that road, I can say the same to you to provide evidence of what you say is fact. You can't just as much as I can't.

You stated a 200hp version doesn't result in any increase in durability. When you make a statement, be ready to defend it. And no, "I worked in the industry" is not a defense - rather, it's lack of defense.

Tech jargon? B10 and B50 percentages are what is used in the manufacturing world to measure an engines reliability given certain variables. If you are discussing an engines reliability under certain conditions or load(which we are) then they apply. I am sure that using Google to look up "what is B10 engine life" to know what I referring to

Do you always give lectures thinking no one knows as much as you?

Re-read what I said - saying B10 AND B50 together, is redundant. In this context, if B10 goes up/down, then obviously B50 does as well.

Hold on. let me go back......Nope, not once did you ask to back up anything so that statement is false. Again, of you want to go down that road then I can and will ask you to back up your statements and you will not be able to as well since they are based on theory and not fact.

Here's my reasoning - I hope you agree an engine at cruise, making 50hp will last longer, in hours, than an engine at WOT redline, correct? I don't think I need to prove this one - it's basic powertrain engineering 101.

The 200 hp engine is essentially a 300 hp engine at 66% throttle. Factoring emissions and thermal constraints, the engine at 200hp may experience even less than 66% of the thermal/mechanical stress.

So logically, how does the 200 hp engine NOT last longer?

No, I don't totally agree. Because just like the video link I posted stated, a restricted VG turbo has more drive pressure(back pressure) than a a correctly fixed FG turbo even with the same compressor size. The reason for higher EGT's is because their is not enough air for the amount of fuel being injected which is generally due to the VG turbos restrictive turbine side, not compressor side. A turbo with a higher CFM will reduce EGT's at the same load and will also require lest boost pressure t achieve the same power output.

However, stock VG turbo's are used primarily for emissions purposes even though their high drive pressures and EGT's reduce the reliability of the engine. In instances where the Cummins 6.7L does not have to meet such strict emissions requirements, a fixed geometry turbo is used like the one on e the marine 6.7L that achieves 550 hp and 1,250 lb-ft.

You also do not know what the internals of these engines can handle and I have seen what they can reliably. If an engine's internals can handle say 800 hp reliably due to its design and build quality, then putting 550 hp versus 200 hp will have no effect on these internals. This is what I am trying to tell you by talking about the turbo. It and the amount of pressure and volume from the HPFP is the limiting factor in reliability at higher power power numbers while also meeting emissions. The internals can reliably handle way more than what these two are capable of in stock form.

Once again, no one compared a VG turbo vs fix geometry. We're comparing a 200 vs 300-320 hp highway spec ISB, which both have VG turbines.

Based on this setup, the 200hp version always have lower EGT, IAT, ECT, and piston / exhaust valve temp (based on lower EGT). Agree? Therefore, the 200hp engine lasts longer.

Also, there is no magical hp "limit" of an engine assembly. Everything is on an inverse curve - the higher the hp, the lower the lifespan, up to the absolutely breaking point (represented by the metal's UTS @ that working temperature). You can't say "an ISB has a working limit of 750hp", metallurgical fatigue limit doesn't work that way.

Okay, well then back up your statements because all I am seeing is a bunch of assumptions based on nothing.........

Re-read my writing instead of trying so hard to prove me wrong. I'm using logic based on engineering. Not once did I say "I say so because I've worked at XXX for XX years".

Remember, we're all trying to learn here, not to say who's right who's wrong...

Cummins12V98 wrote:
Test drove a BigHorn 2019 DRW today. Quieter than mine by a bit and maybe a bit quicker but not by much. A touch over 73k sticker.

Did you notice the new track bar bracket design?

RoyJ wrote:

Still waiting for you to show me evidence the same engine at 500hp with no life reduction over a 200hp variant, which defeats every engineering principal. I'm guessing you have a big fat zero

Still waiting? Where did I say I will show you evidence in the first place. I went back though out our conversation and didn't see a single point where I said this so i am not sure what your are seeing. However, if you want to go down that road, I can say the same to you to provide evidence of what you say is fact. You can't just as much as I can't.

RoyJ wrote:
Saying B50 and B10 together is redundant - throwing tech jargons doesn't make you sound smarter...

Tech jargon? B10 and B50 percentages are what is used in the manufacturing world to measure an engines reliability given certain variables. If you are discussing an engines reliability under certain conditions or load(which we are) then they apply. I am sure that using Google to look up "what is B10 engine life" to know what I referring to

RoyJ wrote:
Did I say I don't understand how variable geometry works? Or that I need a lecture on it?

I asked you to back up your statement that 2 of the same engine, with the same VG turbine + compressor, why the lower hp version won't live longer.

Hold on. let me go back......Nope, not once did you ask to back up anything so that statement is false. Again, of you want to go down that road then I can and will ask you to back up your statements and you will not be able to as well since they are based on theory and not fact.

RoyJ wrote:

Do you agree since the compressor is the same, at lower hp we're operating at a lower pressure ratio? Do you agree a lower pressure ratio means lower EGT with the same intercooler? Do you agree lower EGT, plus lower intake air mass / density, means lower EGT and therefore longer life? If you say no I want to see equations backing it up...

No, I don't totally agree. Because just like the video link I posted stated, a restricted VG turbo has more drive pressure(back pressure) than a a correctly fixed FG turbo even with the same compressor size. The reason for higher EGT's is because their is not enough air for the amount of fuel being injected which is generally due to the VG turbos restrictive turbine side, not compressor side. A turbo with a higher CFM will reduce EGT's at the same load and will also require lest boost pressure t achieve the same power output.

However, stock VG turbo's are used primarily for emissions purposes even though their high drive pressures and EGT's reduce the reliability of the engine. In instances where the Cummins 6.7L does not have to meet such strict emissions requirements, a fixed geometry turbo is used like the one on e the marine 6.7L that achieves 550 hp and 1,250 lb-ft.

You also do not know what the internals of these engines can handle and I have seen what they can reliably. If an engine's internals can handle say 800 hp reliably due to its design and build quality, then putting 550 hp versus 200 hp will have no effect on these internals. This is what I am trying to tell you by talking about the turbo. It and the amount of pressure and volume from the HPFP is the limiting factor in reliability at higher power power numbers while also meeting emissions. The internals can reliably handle way more than what these two are capable of in stock form.

RoyJ wrote:
A good engineer always backs up statements with principals, calculations, laws of thermodynamics, etc. A bad engineer, or tech, relies on "years in the industry" in the absence of sound reasoning.

Okay, well then back up your statements because all I am seeing is a bunch of assumptions based on nothing.........

ShinerBock wrote:
Anecdotal? How many engines have collected data showing that a 500 hp 6.7L in a marine application will have reduced B10 and B50 life percentages over a 200 hp 6.7L that goes into a medium duty truck? How much power did you run to know that breaking point of internals? I am going to guess a big fat zero, and if so then what are you basing your statements on?

Still waiting for you to show me evidence the same engine at 500hp with no life reduction over a 200hp variant, which defeats every engineering principal. I'm guessing you have a big fat zero :D

Saying B50 and B10 together is redundant - throwing tech jargons doesn't make you sound smarter...

If you actually tested any turbo diesel engine you would know what this has to do with durability and what drive pressure and high EGT's does to internals. The fact that you don't know speaks volumes.

A VG turbo creates high drive pressure along with thermal stress and is added solely for emissions purposes. This combined with bad timing spikes will blow gaskets and damage other internals. A correctly sized fixed geometry turbo will not only have considerably less drive pressure and produce a lot less heat, but it will make more power with less boost.

Just replacing the stock VGT with a correctly sized fixed geometry will allow you to create more power while reducing stress and heat on the engine internals. However, since these engines are designed and tuned to meet emissions, a VG turbo must be used even at the detriment of the engine.

Here is a good video by Gale Banks going over what I am talking about. It is on a new L5P Durmax, but the same concept still applies to the Cummins 6.7L since it uses a similar turbo setup. LINK

Did I say I don't understand how variable geometry works? Or that I need a lecture on it?

I asked you to back up your statement that 2 of the same engine, with the same VG turbine + compressor, why the lower hp version won't live longer.

Do you agree since the compressor is the same, at lower hp we're operating at a lower pressure ratio? Do you agree a lower pressure ratio means lower EGT with the same intercooler? Do you agree lower EGT, plus lower intake air mass / density, means lower EGT and therefore longer life? If you say no I want to see equations backing it up...

I don't care if you didn't ask. I gave my credentials because it was obvious you did not have any.

EDIT: Correction, the marine engine 6.7L (which abides by less stricter emissions requirements and therefore uses a larger fixed geometry waste-gated turbo) is at 550 hp/1,250 lb-ft, not 500 hp like I stated above.

A good engineer always backs up statements with principals, calculations, laws of thermodynamics, etc. A bad engineer, or tech, relies on "years in the industry" in the absence of sound reasoning.

As a consulting ME, I always tell them: a GM car salesman can be in the industry for 40yrs, and can't find a filler cap on an LS7.

You should know diesels on sport yachts last 5,000 hrs. In standby generators - 20,000 hrs @ 1500 rpm. A gasoline boat engine averages 2 - 3000 hrs. The same engine in a forklift last 20,000+ hrs.

Test drove a BigHorn 2019 DRW today. Quieter than mine by a bit and maybe a bit quicker but not by much. A touch over 73k sticker.

RoyJ wrote:

ShinerBock wrote:
Yes, at least from what I have seen in the dyno cells when I worked at Cummins. The crank and the internals can handle well over what the pick up truck puts out(I am talking hundreds, not tens) without any significant or even notable reduction in B10 and B50 life percentages. Have you seen otherwise in any of the engines you dyno tested when working for an engine manufacturer?

All anecdotal. In markets where there are no emissions, why don't Cummins or anyone offer a 500 kW stationary generator (say in Africa) powered by an ISB?

Anecdotal? How many engines have collected data showing that a 500 hp 6.7L in a marine application will have reduced B10 and B50 life percentages over a 200 hp 6.7L that goes into a medium duty truck? How much power did you run to know that breaking point of internals? I am going to guess a big fat zero, and if so then what are you basing your statements on?

RoyJ wrote:

ShinerBock wrote:
The first draw back is the turbo especially on the turbine side. It is a major bottleneck and causes temps to rise quickly along with high drive pressures which puts a strain on internals(and head gaskets). However, it was made to control emissions at all rpms like all stock VG turbos. It, like the rest of the hardware and tuning is made to meet emissions and therefore very conservative in regards to what it can actually handle.

Not sure what it has to do with durability.

If you actually tested any turbo diesel engine you would know what this has to do with durability and what drive pressure and high EGT's does to internals. The fact that you don't know speaks volumes.

A VG turbo creates high drive pressure along with thermal stress and is added solely for emissions purposes. This combined with bad timing spikes will blow gaskets and damage other internals. A correctly sized fixed geometry turbo will not only have considerably less drive pressure and produce a lot less heat, but it will make more power with less boost.

Just replacing the stock VGT with a correctly sized fixed geometry will allow you to create more power while reducing stress and heat on the engine internals. However, since these engines are designed and tuned to meet emissions, a VG turbo must be used even at the detriment of the engine.

Here is a good video by Gale Banks going over what I am talking about. It is on a new L5P Durmax, but the same concept still applies to the Cummins 6.7L since it uses a similar turbo setup. LINK

RoyJ wrote:

ShinerBock wrote:
Nope, it would not be reasonable at all. At least not with my 20+ years of experience in the medium/heavy duty industry working for various engine/truck manufacturers and dealership groups. How many years have you been the industry to come up with that theory?

I didn't ask for your credentials, and btw, are you a registered engineer or just the tech running the test bench? Why is it not reasonable to assume engines operating at lower power, which experiences lower mechanical and thermal stresses, to incur less warranty repairs?

I don't care if you didn't ask. I gave my credentials because it was obvious you did not have any.

EDIT: Correction, the marine engine 6.7L (which abides by less stricter emissions requirements and therefore uses a larger fixed geometry waste-gated turbo) is at 550 hp/1,250 lb-ft, not 500 hp like I stated above.