The Big Three's New Diesels put on a Dyno

FishOnOne wrote:

blofgren wrote:

ShinerBock wrote:

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

I agree with you as to why the GM won over the Ram. It was in a lower gear at higher rpm making a lot more power. Although it should have been more than just fifteen seconds ahead with its rated power numbers. With traffic, 15 seconds is basically equal time in my book.

The performance of the Ford in the test is more of a head scratcher and I am still thinking it was computer programmed defueling due to high exhaust gas temps. Adding power(more fuel) to any diesel increase EGT's very quickly. With my brother's 450whp(estimated 515hp at the crank) custom tune on his 2012 F350, he can get to 1,200°F EGT's in a matter of seconds at WOT. What decreases EGT's is lower intake temps and a free flowing exhaust. There is not much the manufacturers can do about exhaust back pressure due to the emissions regulations, but they can do something about the intake temps.

Currently Ford is only one without a front air intake which greatly reduces intake temps. GM has it's hood scoop and Ram has it's active air through the grille. IIRC, I wanna say that for every 1°F you lower your intake temp then you lower EGT's by 10-20°F, but I cannot remember the correct numbers. The Ford is also the only one of the three that has a liquid cooled intercooler which are good and efficient with normal driving or towing, but they get heat soaked under long periods of load like the Ike tests. If that intercooler got heat soaked, then the Ford's EGT's would have skyrocketed requiring the ECM to defuel to cool them down on top of already having less power due to hot incoming air.

This actually makes a lot of sense. It's surprising that Ford hasn't addressed the intake air issue, though.

The Ford pulling 30k lbs up the Ike didn't have a intake air issue and I believe it outperformed the ram with similar fuel economy.

blofgren wrote:

ShinerBock wrote:

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

I agree with you as to why the GM won over the Ram. It was in a lower gear at higher rpm making a lot more power. Although it should have been more than just fifteen seconds ahead with its rated power numbers. With traffic, 15 seconds is basically equal time in my book.

The performance of the Ford in the test is more of a head scratcher and I am still thinking it was computer programmed defueling due to high exhaust gas temps. Adding power(more fuel) to any diesel increase EGT's very quickly. With my brother's 450whp(estimated 515hp at the crank) custom tune on his 2012 F350, he can get to 1,200°F EGT's in a matter of seconds at WOT. What decreases EGT's is lower intake temps and a free flowing exhaust. There is not much the manufacturers can do about exhaust back pressure due to the emissions regulations, but they can do something about the intake temps.

Currently Ford is only one without a front air intake which greatly reduces intake temps. GM has it's hood scoop and Ram has it's active air through the grille. IIRC, I wanna say that for every 1°F you lower your intake temp then you lower EGT's by 10-20°F, but I cannot remember the correct numbers. The Ford is also the only one of the three that has a liquid cooled intercooler which are good and efficient with normal driving or towing, but they get heat soaked under long periods of load like the Ike tests. If that intercooler got heat soaked, then the Ford's EGT's would have skyrocketed requiring the ECM to defuel to cool them down on top of already having less power due to hot incoming air.

This actually makes a lot of sense. It's surprising that Ford hasn't addressed the intake air issue, though.

ShinerBock wrote:

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

I agree with you as to why the GM won over the Ram. It was in a lower gear at higher rpm making a lot more power. Although it should have been more than just fifteen seconds ahead with its rated power numbers. With traffic, 15 seconds is basically equal time in my book.

The performance of the Ford in the test is more of a head scratcher and I am still thinking it was computer programmed defueling due to high exhaust gas temps. Adding power(more fuel) to any diesel increase EGT's very quickly. With my brother's 450whp(estimated 515hp at the crank) custom tune on his 2012 F350, he can get to 1,200°F EGT's in a matter of seconds at WOT. What decreases EGT's is lower intake temps and a free flowing exhaust. There is not much the manufacturers can do about exhaust back pressure due to the emissions regulations, but they can do something about the intake temps.

Currently Ford is only one without a front air intake which greatly reduces intake temps. GM has it's hood scoop and Ram has it's active air through the grille. IIRC, I wanna say that for every 1°F you lower your intake temp then you lower EGT's by 10-20°F, but I cannot remember the correct numbers. The Ford is also the only one of the three that has a liquid cooled intercooler which are good and efficient with normal driving or towing, but they get heat soaked under long periods of load like the Ike tests. If that intercooler got heat soaked, then the Ford's EGT's would have skyrocketed requiring the ECM to defuel to cool them down on top of already having less power due to hot incoming air.

transamz9 wrote:

Me Again wrote:

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

A waste gated turbo shoots down your theory of high altitude, as they most likely cram the same amount of air in as at sea level.

They are not waste gated any more are they? I wouldn't think variable vain would need to be waste gated.

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

Me Again wrote:

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

A waste gated turbo shoots down your theory of high altitude, as they most likely cram the same amount of air in as at sea level.

4x4ord wrote:
Here's a theory. All three trucks ran up the hill in about the same time, therefore they were all three putting about the same power to the ground during the run. The Duramax likely ran up in a lower gear than the other two trucks and likely revved a little higher. If the trucks were making the power that the manufacturers claim the Ram would have been significantly behind the other two. I believe the more refined engines, the new Duramax and Powerstroke were not making the kind of power they should have because the computers were slightly limiting the max fuel delivery on account of the high altitude....lower oxygen. Maybe in order to keep emission levels in check? Obviously if more fuel would have been injected in any of those engines they would have performed better. I would really have liked to see the outgoing Duramax involved in the challenge.

ShinerBock wrote:

Huntindog wrote:


A couple of weeks ago, I had to take one of my cars thru emissions. When I pulled in, they hooked it up, then came over and told me that their testing equipment just failed a test that is done between vehicles. They would need to recalibrate it before testing my car. It took about 10 minutes. I have tested cars many times, and never experienced this... I was somewhat apprehensive as I did not want to fail ( A big PITA) but it went fine.

What it showed me is how fast something can go wrong with testing equipment. It worked fine on the car ahead of me, and was out of spec immeadiatly after that car.


One thing is certain. As time goes on, there will be many more tests. At some point it will be pretty obvious if this test, with its large disparity of on the Dmaxes results is actually accurate, or if something went wrong.

Texas only has an OBD emissions certification for their inspections on vehicles from 1996 and up meaning that they only hook up an OBD to make sure there have not been any emission faults. Emissions inspections are only for Houston, Austin, Dallas-FTW, El Paso, and their surrounding counties so I am unsure why they would be inspecting your emissions all the way over in Abilene. Texas engine emission inspections are for gasoline engines only, not diesel. If they did have a faulty machine then it it was probably the probe detecting NOx, CO2, and other emissions not the actual dyno.

With a Dyno, it is very hard to be off from one to the next and if something was off then I am sure they would have caught it in the three pulls they did for each truck. ATS, the place that did the dyno, is is very reputable company in the diesel aftermarket world and they even host the XDP Diesel Power Challenge every year using that very same dyno in the competition. They know what they are doing and if something was not right then I guarantee you they would have caught it and fixed it.

The results are what they are. No need to worry about spilled milk or try to tarnish a reputable company just because you don't like the results. It is what it is and it ain't what it ain't.