Good Sam Club Open Roads Forum: Those that have tuned or programmed
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tow Vehicles

Open Roads Forum  >  Tow Vehicles

 > Those that have tuned or programmed

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Prev  |  Next
ShinerBock

SATX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 11/08/20 09:03am Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:



I know the Cat in my 07 Peterbilt will defuel when it gets too hot on a long hard pull. I suspect my Ford will defuel if ever gets too hot and I hope the Cummins will as well. I see that as a good thing. When TFL pulled 30,000 lbs up to the Eisenhower tunnel I wouldn’t call that a short burst of HP.


As I said, all modern diesels will defuel. Some more than others especially of they have a lot of power. This is one reason why I never care about stock power numbers and those that gloat about them because they don't know any better. Just because a truck has x hp, doesn't mean you are getting that horsepower all the time especially under sustained conditions.

The other other thing is, people believe that a certain condition will force a diesel A to defuel X amount of horsepower, then the very same conditions will force diesel B to defuel the same X amount of horsepower. This is false and it depends on how "hot" the initial power level is.

For example, manufacturers of diesel A may want to post the highest power levels possible for marketing so they post 400 hp even though it cannot sustain that power for very long. So they tune their engine to make the most power possible, and then have the ECU back it off as needed. This is all perfectly legit using SAE standards. So under towing conditions, engine A may need to defuel to 350 hp depending on many variable such as barometric pressure, turbo speeds, trans temps, EGT's and so on. Hotter ambient temps such as 90F exacerbates this issue making it defuel even more than it would at lower temps.

Then you have the manufacturer of diesel B who may want to give their customer sustained numbers so they tune their engine to 350 hp even though can easily do the same power levels as engine A and back it down as needed. Since engine B is tuned for sustained power, it does not need to defuel and cut power in the same type of conditions. It may eventually need to defuel, but it will take a lot more to get it to that point of cutting power from the stock power levels since the stock tune was very conservative to begin with.

Generally, when someone says that a truck feels more labored with a load, then that is a clear sign that it is in the category of engine A. Adversely, when someone says that an engine does not feel that it has to work harder with more load or that higher loads do seem to effect it as much, then it is in category B.

I will also point out that what is happening in the engine A example is essentially how it is with my tunes except I back it down myself instead of the computer. Unloaded, I keep it on my highest power level. Towing, I will lower the power levels(defuel) on the fly depending the load and temps. Just because it is safe for me to tow 12k lbs in 40F at 500 hp at 50F, does not mean I can do the same at 95F.

There are many variables that come into play that you have to be mindful of. Hence the reason why I tell people that do not have gauges or want the computer to do all the work for them to just leave it in the lowest power level possible. Higher power levels are for those who have gauges, know what they are doing, and know what are the limits of the truck. There is a reason why heavy duty trucks had so many gauges and the professional drivers had to know what those gauges meant back in the day. Now, with computer controlled engines, it is not as important to have all the gauges since the computer will keep the truck within safe limits so the need for professional drivers is becoming a thing of the past and are being replaced by steering wheel holders.

* This post was last edited 11/08/20 12:38pm by ShinerBock *   View edit history

4x4ord

Alberta

Senior Member

Joined: 12/23/2010

View Profile



Posted: 11/08/20 01:58pm Link  |  Quote  |  Print  |  Notify Moderator

Could be the more sustainable torque/power numbers are those that are made for medium duty applications ... so for the 6.7 Cummins and Powerstroke the number is around 750/330 torque/power as compared to the pick up truck ratings.


Edit: our Peterbilt doesn’t provide enough water cooling to prevent defueling on a hot day and the 15 litre Cat makes 550 crankshaft hp .The comparatively small rad on my pick up is going to have its work cut out for it trying to deal with 475 HP.

* This post was edited 11/08/20 02:18pm by 4x4ord *


2017 F350 SRW Platinum short box 4x4.
B&W Companion
2008 Citation Platinum XL 34.5

ShinerBock

SATX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 11/08/20 03:18pm Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

Could be the more sustainable torque/power numbers are those that are made for medium duty applications ... so for the 6.7 Cummins and Powerstroke the number is around 750/330 torque/power as compared to the pick up truck ratings.


Edit: our Peterbilt doesn’t provide enough water cooling to prevent defueling on a hot day and the 15 litre Cat makes 550 crankshaft hp .The comparatively small rad on my pick up is going to have its work cut out for it trying to deal with 475 HP.


The 6.7L cummins gets up to 360hp/800lb-ft in medium duty/bus/RV application and 550 hp/1,250 lb-ft in marine applications. Marine engine can sustain that much due to using sea water to cool the engine and they have lower emission requirements. The engine is mostly identical to the on road 6.7l aside from not having an EGR, larger injectors, and a larger wastegated turbo. The lower numbers on the medium duty/bus/rv applications are mainly due to different emissions standards.

When I tow in my 475hp at the wheels tune, I very seldom even need to use the 548 crank hp unless I am passing. I am generally at around 1,800 rpm most of the time. It is the 1,100 lb-ft at the wheels at 1,800 rpm that I use more often. Even in the Texas heat, my temps are always where they should be. If they ever start to get too hot then I will lower it down to the 425 hp at the wheels tune or the 400 hp at the wheels tune.

Difference between QSB 6.7L and ISB 6.7L

Q stands for off highway engine and I stands for on highway.

* This post was last edited 11/08/20 04:07pm by ShinerBock *   View edit history

ShinerBock

SATX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 11/08/20 03:26pm Link  |  Quote  |  Print  |  Notify Moderator

I will say that another thing that limits stock trucks with VG turbos is drive pressure. A 1:1 drive pressure is ideal, but VGTs at high power levels tend to increase drive pressure way past boost pressure which is the equivalent to a person trying blow up a plastic bottle. It puts a lot of stress on the internals and head gaskets are generally the first thing to give.

This is one of the reason I replaced mine with an old fixed geometry turbo. The main reason why manufacturers are forced to use VGTs is due to low rpm emissions and for better control over the EGR. If it wasn't for this, they would still be using fixed geometry turbos.

LanceRKeys

Amarillo, TX

Senior Member

Joined: 06/04/2017

View Profile


Offline
Posted: 11/08/20 04:35pm Link  |  Quote  |  Print  |  Notify Moderator

My tuner doesn’t save me much time on a 5 hour drive, it may save a down shift (standard transmission) but I like to tinker with things, so I enjoy seeing what the truck will do.

4x4ord

Alberta

Senior Member

Joined: 12/23/2010

View Profile



Posted: 11/08/20 10:36pm Link  |  Quote  |  Print  |  Notify Moderator

ShinerBock wrote:

4x4ord wrote:

Could be the more sustainable torque/power numbers are those that are made for medium duty applications ... so for the 6.7 Cummins and Powerstroke the number is around 750/330 torque/power as compared to the pick up truck ratings.


Edit: our Peterbilt doesn’t provide enough water cooling to prevent defueling on a hot day and the 15 litre Cat makes 550 crankshaft hp .The comparatively small rad on my pick up is going to have its work cut out for it trying to deal with 475 HP.


The 6.7L cummins gets up to 360hp/800lb-ft in medium duty/bus/RV application and 550 hp/1,250 lb-ft in marine applications. Marine engine can sustain that much due to using sea water to cool the engine and they have lower emission requirements. The engine is mostly identical to the on road 6.7l aside from not having an EGR, larger injectors, and a larger wastegated turbo. The lower numbers on the medium duty/bus/rv applications are mainly due to different emissions standards.

When I tow in my 475hp at the wheels tune, I very seldom even need to use the 548 crank hp unless I am passing. I am generally at around 1,800 rpm most of the time. It is the 1,100 lb-ft at the wheels at 1,800 rpm that I use more often. Even in the Texas heat, my temps are always where they should be. If they ever start to get too hot then I will lower it down to the 425 hp at the wheels tune or the 400 hp at the wheels tune.

Difference between QSB 6.7L and ISB 6.7L

Q stands for off highway engine and I stands for on highway.


You're right, towing 13K down the highway is never going to give you an opportunity to put 548 HP to work for any length of time. If you tried pulling something heavy up a long steep grade on a hot day the cooling system would become over tasked in no time. We have engines designed to put out 500 HP all day long. They have 6 foot diameter cooling fans drawing air through absolutely massive radiators.

ShinerBock

SATX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 11/09/20 07:44am Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:



You're right, towing 13K down the highway is never going to give you an opportunity to put 548 HP to work for any length of time. If you tried pulling something heavy up a long steep grade on a hot day the cooling system would become over tasked in no time. We have engines designed to put out 500 HP all day long. They have 6 foot diameter cooling fans drawing air through absolutely massive radiators.


And that is the reason why I know all of these 400+ crank horsepower on these stock trucks is BS under sustained conditions towing these 30k tow ratings. You might be able to sustain more than 400 hp at the crank on a truck with modifications to handle it, but not with the coolant system on stock trucks having to cool down both the engine and exhaust gasses. Then you have the bottleneck of the DPF in the exhaust creating higher EGT's for the EGR cooler to try and cool down.

I will say that towing 17-18k gooseneck trailer with little wind drag puts less constant stress on my truck at highway speeds than a 13-14k 5ver does in terms of temps. I have never taxed the dual radiators in my truck to that extent mainly because I purchased a truck to tow around 14k and would have went with a different setup if I needed to tow more.

Back when I worked at one of our dealerships as an area sales rep, I had many oil field customers across Texas who also had locations up in Colorado. I relied on several hot shot companies to deliver to the various customer locations and I got to know them very well. They were actually the ones gave me advice on my set up since most of them drove Ram CTD's as well. Anyways, the ones that were deleted and tuned generally stated they leave their trucks in the 425 hp at the wheels tune no matter what they tow. That is close to 500 hp at the crank. I don't tow as heavy as their DRW trucks do so I can get away with a higher power level without taxing the cooling system especially unloaded. They also recommended that I leave it in the lowest tune possible or at stock power if I were going to choose emissions intact tuning.

* This post was last edited 11/09/20 01:44pm by ShinerBock *   View edit history

4x4ord

Alberta

Senior Member

Joined: 12/23/2010

View Profile



Posted: 11/09/20 07:14pm Link  |  Quote  |  Print  |  Notify Moderator

Is EGR/EGR cooling still much of a factor now that the NOx is being controlled with DEF? (EGR is used much less and the fact that it lowers combustion temperature should offset, to some degree, the taxing of the cooling system caused by the EGR cooler) Any idea how the surface area of the radiators on the new Fords compare to the surface area of the air to air and radiator on the Ram? Does the current Ram use the same cooling system that they used on the 385 hp/865 lbft engine. It would be interesting to know how many btu/min these pick up truck cooling systems can dissipate vs the cooling system on something like a class 8 highway tractor.

ShinerBock

SATX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 11/09/20 07:48pm Link  |  Quote  |  Print  |  Notify Moderator

Coolant still flows through the EGR cooler regardless of whether the EGR valve on the other side of the cooler is open to let cooled exhaust escape into the intake or not. You also have coolant cooling down the electronic turbo actuator which gets very hot.

I don't care about the surface area of the new Ford's or Ram are and don't want to make this into a fanboy p!$$ing contest thread of comparing trucks neither if us own or drive. This thread is about tuned diesels and how well they tow at different power levels which I am providing my own real world experience on.

* This post was edited 11/09/20 09:05pm by ShinerBock *

4x4ord

Alberta

Senior Member

Joined: 12/23/2010

View Profile



Posted: 11/10/20 04:40am Link  |  Quote  |  Print  |  Notify Moderator

I was able to find the dimensions of the radiator used on the 2013 - 2018 Ram. It has a surface area of 588 square inches. For comparison the rad used on a 2008 - 2016 Peterbilt class 8 has a surface area of 1672 square inches. It seems to me that a person better be watching his gauges very closely if he’s going to tow with a tuned truck. Years ago I added power to a Duramax and destroyed the transmission towing with it.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Prev  |  Next

Open Roads Forum  >  Tow Vehicles

 > Those that have tuned or programmed
Search:   Advanced Search

Search only in Tow Vehicles


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.