RoyJ wrote:
For the hundredth time, because passing emissions is a GIVEN. You don't sell cars without doing so first.
Yes, and is one of the major reason why OE's have to detune engines to meet them. However, aftermarket tuning does not. So just because the aftermarket increases power by tuning out these emissions does not mean it reduces the reliability of the engine like what was inferred earlier.
RoyJ wrote:
If you want to talk marine specs, I can go on all day. Cummins is very specific about how long each power level should be used for, and at what vessel weight, and how to prop for each weight.
Point?
Point is, Cummins can increase power output on the marine engine due to less stringent emissions requirements as they stated.
RoyJ wrote:
All about longevity at a given duty cycle.
Please re watch the videos because the very people who are making these trucks says otherwise.
RoyJ wrote:
And before you say it again, yes, meeting emissions is a GIVEN.
It is a given for the OE, it is not for the aftermarket tuners.
RoyJ wrote:
The important part? Passing emissions as a result of LOADING. In other words, duty cycle (how much and how long an engine is loaded for).
It is not because chassis trucks, or class 8 trucks have tighter emissions. But rather, because of their higher loading, it's tougher to meet the SAME emissions.
So guess what happens if you met chassis cab emissions while making 385 hp? Surprise - the engine won't meet longevity targets!
I would advise you to read the re-read the emissions link I provided which shows their are various DIFFERENT emissions tests depending on vehicles type. They are not all the same.
Here is additional link from the EPA that further explains the DIFFERENT emissions requirements for each category.
Applicable Engine Test Procedures for Each Engine Category RoyJ wrote:
Every power rating is based on the assumption of passing emissions, the ONLY difference is loading conditions (aka duty cycle).
There's no difference in "emissions tier" in Cat's duty cycle ratings, that's a constant factor.
It doesn't matter if CAT does not stated in their sales pamphlet, their are tiers and bins for each application and even more so there are also fleet averages as well.
Please reread the EPA link above. I believe the EPA makes the rules, not CAT.
RoyJ wrote:
I also didn't mention the truck has to pass modern crash tests, have air bags, or ABS/traction control. Because they're also a GIVEN. You don't sell a vehicle without it.
Audi's SQ5 also had revised heads, pistons, and turbos, just to squeeze out 20 hp over a standard Q5. Oh, did I mention they have to do so while meeting emissions?
No, because it's a GIVEN.
I think you need to back track and re-read what this debate is about. You inferred that the power levels are mainly what they are due to reliability without "at 385 hp have nothing left to tune without hurting durability"(<--your exact words).
I, however, said the 6.7L was limited 385 hp is mostly due to emissions(which tuners do not have to abide by)and increasing power by removing these emission limitations can easily be had without reducing reliability or durability.
You then rebutted saying that power levels are what they due to durability in their duty cycle even though the Ram engineer stated that that is not the case. They are emissions limited, and removing these limitations and increasing power (to an extent) will not necessarily reduce reliability. In many cases it will actually increase reliability through less fuel dilution, not having exhaust gas rerouted into the intake, not having so many injector events due to pilot injection, lower EGT's, and so on.
That is what this is all about, I feel this needs to be stated because you seem to be changing the debate into something else.
Also, I am not sure you know how emissions load tests works. It is not a duty cycle test since they duty cycle is not known at the time of testing because the engine is not matted to a final chassis. They do not know what these trucks will be used for so it is based on GVWR and a few other things. They run the engine through the test and reduce the power output to meet the emissions restriction of each category.
Some categories you can get away with multiple power outputs which many times the manufacturer will take advantage of by charging more for the higher power unit. Similar to what Cummins does with the 6.7L and how the regular output is 370hp/800lb-ft and the HO version is 385hp/930lb-ft. Or an even better example is the new X15 efficiency series which ranged between 400-500 hp versus the X15 performance series which ranges from 485hp to 605 hp. They are the same internally aside from injectors and turbos.
