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184 Replies
- couple notes from the video ...
New water pump...again... and the "scissor" gear for the fuel pump is a very interesting design if you pause and study the gear.
ok...now you guys can get back to who said what ;) RoyJ wrote:
ksss wrote:
There is more to winning the pull off contest then speed up the hill, number of brake applications on the way down and the subjective points. You might want to check it out. I do have a CDL and do tow 30K plus routinely with my Duramax trucks up and down passes, including Teton pass. I wish they would spec the trucks to their capability, for whatever reason, they don't. However speaking of speed and controllability of a load, the Duramax typically wins the IKE test. It may not be a perfect test but it is pretty comprehensive.
I've watched plenty if Ike Gauntlet runs (if you're talking about TFL truck w/ "Mr. Truck"). It's mostly entertainment.
My point is everything on the run is performance based. OEMs have to consider more, such as chassis longevity. When RAM made the jump to 30k tow ratings in 2013, they had to upgrade to a stronger frame, with new front suspension, and axles. This time RAM upgraded the chassis again to go to 35k lbs.
No one knows if the current GM chassis is strong enough, we do know it's by far the oldest. Powertrain wise, no doubt the Duramax is plenty strong.
Because Ram had to continue to increase chassis strength several times doesn't mean GM needs to. Maybe GM built their chassis with increases in mind and Ram didn't, I don't know and neither do you. If you want to move the goal posts that is fine and discuss longevity that is fine as well. The point I am making is that from a performance standpoint, the GM HD's have proved year after year regardless of what the engine ratings are they are at least competitive if they don't win outright, which they usually do. You may not think those Ike runs have value and that is fine, but it is the only venue that compares these trucks in a uniform way. I know they don't take everything into account, but I am not sure how chassis durability could ever be incorporated into them. I would imagine if they did and Ram lost that segment we would be talking about some other unmeasured segment.Cummins12V98 wrote:
4x4ord wrote:
When GM wants to increase tow rating numbers they will add a 4:10 axle to their list of options.
2018 DRW Crew 4x4 RAM SAE tow rating is 25,020# with 3.73's and GM's same configuration is 22,700#.
Will be interesting to see what they come up with when the new trans is available.
You need to think about what gears are for and what is required to get a heavy trailer moving ... especially in soft ground or on an incline. The Asin has a low gear ratio of 3.74:1 and the Allison has a first gear ratio of 3.1:1. If you put a 3.42 axle ratio behind the Asin and a 4.10 axle ratio behind the Allison the overall gear ratios would be similar. So a 4.10 equipped Chevy would pull a heavy trailer out of a bog about the same as a 3.42 equipped Ram.RoyJ wrote:
Not sure why you brought up emissions - of course it trumps durability because not passing emissions means you don't sell engines period! I assumed that was a given.
Because stock engines are tuned(or de-tuned) to meet emissions. They can safely increase power with hurting reliability, but they can't do it AND meet emissions. The notion that stock engines are maxed out in power due to reliability reason is completely false for most engines these days.RoyJ wrote:
In this context, tell me how: a new graphite block, stronger pistons / rods, better flowing head, and turbo geometry is emissions driven. The CP4 pump, sure, mostly emissions. But I simply pointed out how far Cummins went just to improve a relatively minor performance gain.
Most of that is not for emissions per say, but rather to reduce weight for the upcoming CAFE regulations that will include class 2b and above trucks for the first time in the next few years. The turbo and heads help keep EGT's low when coupled with emissions devices and also reduce PM. That is the whole reason diesels went to VGT even though they are not as reliable as fixed geometry turbos, to better control emissions by regulating air and fuel.RoyJ wrote:
This ONLY happens on low tune engines neutered on purpose for fleet purposes. If you had a 425 hp ISX, then sure, you can go to a dealer and get it re-rated for say 475 hp. But in most cases you won't have a 600hp rating available without at least injector changes.
Yeah, because fleets don't want to pay for the higher power variants of the engine so they buy the de-tuned version even though the only the that separates their from the higher power version is ECM tuning.RoyJ wrote:
We're talking about an engine tune that's already maxed out. An ISB at 385 hp have nothing left to "tune", without hurting durability. Out in the commercial world, I've never seen one at 385 hp, even at RV and fire apparatus duty cycle.
No, an ISB 6.7L is no where near maxed out. I have seen it in the dyno test cells at Cummins when I worked there and in the after market. Heck, mine makes over 500 rwhp even with the emissions intact. However, as I said before it cannot do it AND meet emissions.
The reason you have never seen 385 hp in the commercial world is because those engines have to go through different dyno certifications. A pickup goes through what is called a chassis dyno certification since the vehicle it will be going is complete and an incomplete truck(no bed) goes trough what is called an engine dyno certification because the chassis it is going in is not complete leaving the factory. These two certifications have different regulation depending on the emissions bin and tier of the truck it is going in.
It has more to do with emissions rather than duty cycle. Duty cycle will not hurt the engine at higher power levels since the engine will de-fuel(cut power) if any of the sensors detect any of the temps will hurt the engine.- "Looks like you are wrong on the Aisin too. Here is the video on the powertrain where he says the new Aisin tranny. video In this next video he talks how they had to beef up the "medium duty" Aisin as you call it to be able to handle the power, around the 5:30 mark. video"
What did "I" say that was wrong??????
It's not ME calling it MD it simply IS.
He said it needed to be "updated" - "This time RAM upgraded the chassis again to go to 35k lbs."
MANY more changes to support this SAE tow rating. ShinerBock wrote:
Nope, I worked at Cummins and can honestly tell you that while reliability is high on the list, it is not the most important thing, passing emissions is. In fact, reliability is even decreased in the way of EGR's, unproven fuel pumps, and less reliable VGT for the sole purpose of meeting emissions.
The OE's have to pass a dyno certification in order to sell their engines so they have to tune it to pass these tests as well as providing a safe generic fuel mapping for many users in many applications and many scenarios. The aftermarket does not have to pass a dyno certification. Well..... they have to, but most don't
Not sure why you brought up emissions - of course it trumps durability because not passing emissions means you don't sell engines period! I assumed that was a given.
In this context, tell me how: a new graphite block, stronger pistons / rods, better flowing head, and turbo geometry is emissions driven. The CP4 pump, sure, mostly emissions. But I simply pointed out how far Cummins went just to improve a relatively minor performance gain.Also, Cummins does add power to many of their engines via tuning without changing any of the hard parts all the time. They did it with the 6.7L, ISX, ISL, and many other engines. In fact, they even offer different power ratings on the same engine and you have to pay higher cost for the added power depending on how the truck is used. Almost all of the diesel manufacturers do this in the medium and heavy duty industry. Heck, my customers used to be able to pay a nominal fee for the licence from CAT to have their engines turned up by one of my 120 dealers. All that was involved was loading a tune that came from CAT.
This ONLY happens on low tune engines neutered on purpose for fleet purposes. If you had a 425 hp ISX, then sure, you can go to a dealer and get it re-rated for say 475 hp. But in most cases you won't have a 600hp rating available without at least injector changes.
We're talking about an engine tune that's already maxed out. An ISB at 385 hp have nothing left to "tune", without hurting durability. Out in the commercial world, I've never seen one at 385 hp, even at RV and fire apparatus duty cycle.Cummins12V98 wrote:
Huntindog wrote:
Cummins12V98 wrote:
You have stated this repeatdly.
" I wish they would spec the trucks to their capability, for whatever reason, they don't."
They simply don't have the transmission that can pass the SAE test. You may be towing 30k and no doubt it tows just fine BUT it would not pass the SAE test.
New transmission will no doubt significantly increase the tow rating. Anxious to hear why now with the new transmission they have a higher rating since they said basically there is no need for a higher rating than 22,300#.
Just what is this test?
If it is the "J" towing standard, the only parameter in that test I recall that relates to the tranny is the fluid temp. Since I own one of these, I am well aware of what the tranny temps run, and am very confident that would not be an issue.
If there is some other SAE test that I am unaware of, or I have missed something, please enlighten me.
Look it up, it's the repeated launch on grade forward and reverse. I am sure that is the one it can't pass. SAE J2807
If this is NOT the reason for the LOW tow rating then please explain what is. The engine has plenty of power to do the job.
Remember the Allison is NOT the same in the pickups as it is in the MD applications.
AISIN is the same whether it's in a RAM or another Manufacturers Medium Duty vehicle.
Looks like you are wrong on the Aisin too. Here is the video on the powertrain where he says the new Aisin tranny. video In this next video he talks how they had to beef up the "medium duty" Aisin as you call it to be able to handle the power, around the 5:30 mark. videoksss wrote:
There is more to winning the pull off contest then speed up the hill, number of brake applications on the way down and the subjective points. You might want to check it out. I do have a CDL and do tow 30K plus routinely with my Duramax trucks up and down passes, including Teton pass. I wish they would spec the trucks to their capability, for whatever reason, they don't. However speaking of speed and controllability of a load, the Duramax typically wins the IKE test. It may not be a perfect test but it is pretty comprehensive.
I've watched plenty if Ike Gauntlet runs (if you're talking about TFL truck w/ "Mr. Truck"). It's mostly entertainment.
My point is everything on the run is performance based. OEMs have to consider more, such as chassis longevity. When RAM made the jump to 30k tow ratings in 2013, they had to upgrade to a stronger frame, with new front suspension, and axles. This time RAM upgraded the chassis again to go to 35k lbs.
No one knows if the current GM chassis is strong enough, we do know it's by far the oldest. Powertrain wise, no doubt the Duramax is plenty strong.4x4ord wrote:
When GM wants to increase tow rating numbers they will add a 4:10 axle to their list of options.
2018 DRW Crew 4x4 RAM SAE tow rating is 25,020# with 3.73's and GM's same configuration is 22,700#.
Will be interesting to see what they come up with when the new trans is available.
