Those that have tuned or programmed

You have no reason to be concerned. You’re not towing anything more with your truck than what it was designed for. You don’t need cooling for power your not using.

Well, I will let my hot shot buddies who have put well over 300k miles towing with the 400+hp at the wheels that a guy on a forum who has never owned a tuned and moded truck like theirs did the math on their radiator sizes and said they better be watching their gauges because they are pushing it. I am not concerned, but maybe your math is enough to trump their real world experience and make them more concerned.

God forbid they make more power than the mighty 475 crank hp Powerstroke. Something has to be found wrong if they do because only that engine was built to handle it.

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.

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.

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.

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.

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.

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.

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.

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.