2020 GM/Chevy gas 6.6L max towing test

[ib516]

VIDEO

[LITEPHIL]

For the weight they were towing and at that altitude, I think it did ok for a small block non turbo gas engine. That thing was probably gasping for air. Part of finding the true towing potential would be shifting gears manually if needed. I couldn't watch the whole thing since that one guy sort of gives me the creaps. It will be interesting to see a comparison with the Ford and Dodge gas engines. I very much doubt they'll do that much better. Gas,extreme weight and altitude are not the gas engines best friend.

[deltabravo]

The 2020 Chevy HD is still ugly as sin.

I saw one in person a few weeks ago, they are extremely tall too.

2020 Chevy HD - too tall for my liking.

[ShinerBock]

ls1mike wrote:

ShinerBock wrote:

ls1mike wrote:

Lynnmor wrote:

jfritz_drfritz wrote:

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

I wonder if sensors saw high temperatures after miles of full throttle and dialed back the power to save the engine or transmission.

In this video and the 2017 gasser video they mention all temps were in spec.

But that is just it. It could have defueled or cut power to keep the temps within spec. Diesel do the same thing. The Ram 6.4L did it as well the last Ike run they had. This 6.6L could have forced the truck into lower rpms to keep the temps at safe levels.

Right, but that is not a parameter in the transmission field. There are something close to 450 parameters for the 6L80E/6L90E. For the 6L80E and 6L90E time and pressure are the tow big ones. I will hook up the Laptop next time I tow and see. I don't remember reading about or being able to mess defueling in the program. I have HP Tuners. That thing is great if you understand it. It has really woke the Caprice up with the cam swap. I don't plan on messing with the truck at all. It is a great diagnostic tool too. Like I know guys who remove torque management. Not really worth it to me, I don't feel like rebuilding the 6L80E in the Caprice every other season.

You may not be able to all perimeters depending on the software or tuning tool you are using. I know I can see more perimeters with my EFI Live software than I can with my MM3. EFI Live is by far the best when it comes to how many parameters it can view/alter especially when it comes to GM vehicles.

[ls1mike]

ShinerBock wrote:

ls1mike wrote:

Lynnmor wrote:

jfritz_drfritz wrote:

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

I wonder if sensors saw high temperatures after miles of full throttle and dialed back the power to save the engine or transmission.

In this video and the 2017 gasser video they mention all temps were in spec.

But that is just it. It could have defueled or cut power to keep the temps within spec. Diesel do the same thing. The Ram 6.4L did it as well the last Ike run they had. This 6.6L could have forced the truck into lower rpms to keep the temps at safe levels.

Right, but that is not a parameter in the transmission field. There are something close to 450 parameters for the 6L80E/6L90E. For the 6L80E and 6L90E time and pressure are the tow big ones. I will hook up the Laptop next time I tow and see. I don't remember reading about or being able to mess defueling in the program. I have HP Tuners. That thing is great if you understand it. It has really woke the Caprice up with the cam swap. I don't plan on messing with the truck at all. It is a great diagnostic tool too. Like I know guys who remove torque management. Not really worth it to me, I don't feel like rebuilding the 6L80E in the Caprice every other season.

[ShinerBock]

ls1mike wrote:

Lynnmor wrote:

jfritz_drfritz wrote:

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

I wonder if sensors saw high temperatures after miles of full throttle and dialed back the power to save the engine or transmission.

In this video and the 2017 gasser video they mention all temps were in spec.

But that is just it. It could have defueled or cut power to keep the temps within spec. Diesel do the same thing. The Ram 6.4L did it as well the last Ike run they had. This 6.6L could have forced the truck into lower rpms to keep the temps at safe levels.

[ls1mike]

Lynnmor wrote:

jfritz_drfritz wrote:

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

I wonder if sensors saw high temperatures after miles of full throttle and dialed back the power to save the engine or transmission.

In this video and the 2017 gasser video they mention all temps were in spec.

I am going to look at the Caprices tune tonight. It is pretty similar to the truck believe it or not.
I know the Caprice looks at speed/rpms/time/MAF/TPS. I will have to look and see it temp is part of it.

I really messed withe Caprice when I got rid of the AFM cam and installed an LS9 cam.

[ls1mike]

JIMNLIN wrote:

At the end of the test they were going 2600 RPM at 25 mph. Truck wouldn't downshift. I wonder what would have been different if they put it in manual. To be honest I never put mine in manual, but I have not towed the IKE.

I use manual mode in a auto tranny for that type towing. I made a living for over 11 straight years with manual transmission LDTs so I know better than the ECM which gear to select and at what point a gear shift is or isn't needed.


Of course these test are better suited to for those that don't want to do the thinking/shifting for which gear is needed at that moment.
Results would be different up and down hill using manual mode by a experienced operator........or a smarter engine/tranny operating ECM.

I just have not had to use it in this truck. They old truck was 4 speed. I would leave it in third sometimes. I am not towing really heavy and here in Washington we don't get anything that high in elevation so it stays in the correct gear.

[Lynnmor]

jfritz_drfritz wrote:

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

I wonder if sensors saw high temperatures after miles of full throttle and dialed back the power to save the engine or transmission.

[JIMNLIN]

At the end of the test they were going 2600 RPM at 25 mph. Truck wouldn't downshift. I wonder what would have been different if they put it in manual. To be honest I never put mine in manual, but I have not towed the IKE.

I use manual mode in a auto tranny for that type towing. I made a living for over 11 straight years with manual transmission LDTs so I know better than the ECM which gear to select and at what point a gear shift is or isn't needed.


Of course these test are better suited to for those that don't want to do the thinking/shifting for which gear is needed at that moment.
Results would be different up and down hill using manual mode by a experienced operator........or a smarter engine/tranny operating ECM.

[ls1mike]

jfritz_drfritz wrote:

ls1mike wrote:

ShinerBock wrote:
There should be a caveat with N/A gaser tow ratings such as you loose X pounds of rating every Y feet above elevation instead of just saying it can tow 16,000 lbs. Unless doing 25 mph at 5,000 rpm without any power to pass is your idea of towing.

At the end of the test they were going 2600 RPM at 25 mph. Truck wouldn't downshift. I wonder what would have been different if they put it in manual. To be honest I never put mine in manual, but I have not towed the IKE.

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

Based off the tuning I have done with my cam upgrades in my 2000 WS6 and my 2014 Caprice which is a 6.0/6L80E so similar. I will bet it is the amount of air the computer sees VS throttle position VS actual RPM.

[jfritz_drfritz]

ls1mike wrote:

ShinerBock wrote:
There should be a caveat with N/A gaser tow ratings such as you loose X pounds of rating every Y feet above elevation instead of just saying it can tow 16,000 lbs. Unless doing 25 mph at 5,000 rpm without any power to pass is your idea of towing.

At the end of the test they were going 2600 RPM at 25 mph. Truck wouldn't downshift. I wonder what would have been different if they put it in manual. To be honest I never put mine in manual, but I have not towed the IKE.

I wonder if it fails to downshift because at that altitude the engine doesn’t generate enough torque for the transmission to sense a downshift point

[blofgren]

ShinerBock wrote:
The current CP4.2 is not the same as the old one that was notorious for failing on the 2011-2015 Ford and GM trucks. There is a different cam profile among other things and the max pressure was raised from 29k to 36k.

I believe the new Cummins is only pushing out 29k psi which plays a huge role in the pumps longevity and reliability since it is not utilizing the pump to its max capacity like Ford and GM were with the old CP4.2. The new 2020 PSD is utilizing 36k psi from the new CP4.2.

Interesting info. It will be interesting to see how these pumps do in both the new Ram and Ford. I won’t be personally experimenting though because I’m holding on to my trusty CP3 powered truck! 🙂

[ShinerBock]

The current CP4.2 is not the same as the old one that was notorious for failing on the 2011-2015 Ford and GM trucks. There is a different cam profile among other things and the max pressure was raised from 29k to 39k psi.

I believe the new Cummins is only pushing out 29k psi which plays a huge role in the pumps longevity and reliability since it is not utilizing the pump to its max capacity like Ford and GM were with the old CP4.2. The new 2020 PSD is utilizing 36k psi from the new CP4.2.

[FishOnOne]

Flashman wrote:

FishOnOne wrote:

Flashman wrote:

wowens79 wrote:
My biggest concern going diesel is with all the Emmisions **** on them, and the cost to repair it. I know some have no probs, but you read stories all the time of CP4 fuel pump grenading and costing $10k to repair, or $5k Emmisions repairs.

I keep trucks well past warranty, my current truck I've had for 17 years, and 235k miles, and I've had 2 engine repairs. A fuel pump at 195k miles, and at 210k I had new rear main seal, oil cooler lines, valve cover gaskets etc replace because it was dripping oil all over the driveway. Total engine repairs over 17 years is less than $2500.

I'm debating new trucks now, and diesel vs gas is part of the debate. There is no denying that the diesel is a beast towing, but I'm only towing 8000k lbs, and I'm in the southeast, so we've got little hills compared the out west. After 15-20 years resale is not real a huge concern.

I believe the CP4 problem and warranty denial was a Ford problem. GM and RAM seem to have far fewer problems. If you are stuck in the Ford camp then I guess you get what you deserve.

The new Ram Cummins welcomes you to the CP4.2 and all it's glory for years to come.

I wonder if they will deny warranty claims - oh wait that was Ford.

I wouldn't hold my breathe based on FCA's history on handling safety recalls. And that Ram Cummins with the CP4.2 has limited warranty so FCA will stick it to you either way.