40 mph uphill? Other Armada or Titan TVs?

[PaulandAnn]

I’ve been trolling this site for a year. There’s so much info I that haven’t needed to ask a question until now!


Tv: 2006 Armada LE 5.6L DOHC V8 with factory tow package. Tow rating 9000lbs. 305/385 hp/tq
105K miles, added external trans cooler, bypassing in-radiator cooler. Andersen WD hitch which I’m very happy with.

The Armada handles the trailer nicely, it’s the lack of power on the hills that makes the drive so stressful. I chill out once we're through all the hills.

Trailer: 21 ft Jayco. Factory weight with propane: 4385lbs estimate another 350lbs water, a couple hundred lbs food and whatnot. Lets say 5000lbs. (I've weighed the loaded tongue, but not the entire trailer)

(TV cargo: only 2 people and dog)

Driving up out of Phoenix to higher cooler elevations there are several hills/ridges on our way to 7000ft elevation. On every one, I eventually slow to 40mph. Is this normal? Neither trans or engine overheat. I have learned to ignore the “Tow Mode” and just downshift manually to get higher (3000-4000) rpms, for more power and lighter load on torque converter (keeping the trans temp down).

But meanwhile, monster 5th wheel “houses” fly by at 65mph on the same hill towed by their Cummins powered or whatever pickup trucks.

I don’t want a pickup truck. I don’t need one. In our SUV at all times, we have 2 child seats and a large dog crate.

I see the 2018 Ford Explorer with 6 cyl turbo Ecoboost has nearly 100lbs more torque and a 10 speed auto trans. Sounds nice, maybe what I need, but still too pricey.

Are other Nissan owners faring any better than me?

[Atlee]

Of course a turbo loses some efficiency at altitude compared to sea level. However, that doesn't alter the fact that a turbo charged engine is way, way more efficient and better at high altitudes than a NA engine.

I had no problem running at 60-65 on interstates when out in the Rockies recently with my 3.5L Ecoboost engine. And on steep inclines, when forced to slow way down due to a slow vehicle in front of me, I was able to get back up to speed with little effort, little gas pedal, and relatively low RPM's after the interference was eliminated.

Nor did I have any issues going up even steeper 2 lane roads.

boggerr wrote:


You’re absolutely correct. I had boost on my mind, my bad
I do suggest that people that don’t believe higher altitudes effect turbo diesels to do some research on the subject.

[Huntindog]

PaulandAnn wrote:

Keith and Lu wrote:

PUCampin wrote:
There have been a lot of great posts but I would like to add a little more.

Something I caught in your first post is you bypassed the transmission cooling loop in the radiator when you installed the aux cooler. This is a bad idea. ...

In the case of Nissan trucks, it is a common practice. The radiators up to about 2010 have a possible internal flaw where the seal between the rad fluid and the trans fluid breaks, mixing them, destroying the transmission.

My Pathfinder came with a factory installed external transmission cooler. So I had no qualms doing the same.

Exactly. Thank you. I was going to say that but you beat me to it.

The breakdown tends to occur after about 100K miles of heat/cold cycles.

Also, it's said that the main purpose of the in-radiator xmission cooler is actually to WARM UP the xmission to operating conditions in cold climates. Something I don't worry about in Phoenix. The xmission still has it's separate factory main cooler in front of the radiator. I just added another. Much cheaper and WAY easier than replacing the main radiator itself! 🙂
I've tested it towing up to 7000ft and it works great.

Anyway, astute observation of my post PUcampin, but like Keith & I explained...

Too cold or too hot are both bad.
BUT...... The radiator tranny cooler does both exceptionally well. Especially during low speed parking. It is amazing how quickly a tranny can heat up. But with a cooler in liquid instead of air..... The heat transfer in both directions is MANY times greater than air.

And the faulty radiator can be replaced pretty reasonable. My first and only search was autozone... 239.00 lifetime warranty.

[Grit_dog]

I can only imagine the discussion at page 6 didn’t read thru all!
If the op is still here, one thing you can do is keep your foot in it more. 3-4000rpms is low. Between 4000 and 5000 you’re leaving like 40? Hp or so on the table and probably only losing a bit of torque.
Otherwise, yeah there’s plenty of 400+\400+ hp tq SUVs that will pull a lot harder than yours. Depends how much you want to spend.

[PaulandAnn]

Keith and Lu wrote:

PUCampin wrote:
There have been a lot of great posts but I would like to add a little more.

Something I caught in your first post is you bypassed the transmission cooling loop in the radiator when you installed the aux cooler. This is a bad idea. ...

In the case of Nissan trucks, it is a common practice. The radiators up to about 2010 have a possible internal flaw where the seal between the rad fluid and the trans fluid breaks, mixing them, destroying the transmission.

My Pathfinder came with a factory installed external transmission cooler. So I had no qualms doing the same.

Exactly. Thank you. I was going to say that but you beat me to it.

The breakdown tends to occur after about 100K miles of heat/cold cycles.

Also, it's said that the main purpose of the in-radiator xmission cooler is actually to WARM UP the xmission to operating conditions in cold climates. Something I don't worry about in Phoenix. The xmission still has it's separate factory main cooler in front of the radiator. I just added another. Much cheaper and WAY easier than replacing the main radiator itself! 🙂
I've tested it towing up to 7000ft and it works great.

Anyway, astute observation of my post PUcampin, but like Keith & I explained...

[marcsbigfoot20b]

One of the potential problems of high altitude and turbos is that the turbo is actually spinning faster due to the thinner air. So if you have surge issues or really beat on a high mileage turbo you could have problems. Surge is a big turbo destroyer....if you crank up a hill and hear shhh shhh shhh.
Other than that you just won’t ever know what us turbo diesel owners are talking about when we cruise up the mountains unless you try it out for yourself.

[Keith_and_Lu]

PUCampin wrote:
There have been a lot of great posts but I would like to add a little more.

Something I caught in your first post is you bypassed the transmission cooling loop in the radiator when you installed the aux cooler. This is a bad idea. ...

In the case of Nissan trucks, it is a common practice. The radiators up to about 2010 have a possible internal flaw where the seal between the rad fluid and the trans fluid breaks, mixing them, destroying the transmission.

My Pathfinder came with a factory installed external transmission cooler. So I had no qualms doing the same.

[Huntindog]

boggerr wrote:

Huntindog wrote:

Jay Coe wrote:

boggerr wrote:

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

What kind of turbo diesel do you have that idles at 11 to 15lbs of boost?

I’m not going to muck up the OPs thread going back and forth about this, look it up, do some reading about it and how a turbo works

He's not talking about 11-15psi boost, he's talking atmospheric pressure when there's no boost. Jeez, it's no wonder people get so confused!

[COLOR=]Here's your sign. LOL:B

You’re absolutely correct. I had boost on my mind, my bad

No worries. Gave me a good chuckle that I could use.

[boggerr]

Huntindog wrote:

Jay Coe wrote:

boggerr wrote:

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

What kind of turbo diesel do you have that idles at 11 to 15lbs of boost?

I’m not going to muck up the OPs thread going back and forth about this, look it up, do some reading about it and how a turbo works

He's not talking about 11-15psi boost, he's talking atmospheric pressure when there's no boost. Jeez, it's no wonder people get so confused!

[COLOR=]Here's your sign. LOL:B

You’re absolutely correct. I had boost on my mind, my bad
I do suggest that people that don’t believe higher altitudes effect turbo diesels to do some research on the subject.

[Huntindog]

Jay Coe wrote:

boggerr wrote:

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

What kind of turbo diesel do you have that idles at 11 to 15lbs of boost?

I’m not going to muck up the OPs thread going back and forth about this, look it up, do some reading about it and how a turbo works

He's not talking about 11-15psi boost, he's talking atmospheric pressure when there's no boost. Jeez, it's no wonder people get so confused!

Here's your sign. LOL:B

[Jay_Coe]

boggerr wrote:

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

What kind of turbo diesel do you have that idles at 11 to 15lbs of boost?

I’m not going to muck up the OPs thread going back and forth about this, look it up, do some reading about it and how a turbo works

He's not talking about 11-15psi boost, he's talking atmospheric pressure when there's no boost. Jeez, it's no wonder people get so confused!

[richclover]

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

Bottom line: If you wanna haul and tow in the high country, turbo the diesel.

C’mon up!

[boggerr]

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

What kind of turbo diesel do you have that idles at 11 to 15lbs of boost?

I’m not going to muck up the OPs thread going back and forth about this, look it up, do some reading about it and how a turbo works

[naturist]

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.

[PUCampin]

There have been a lot of great posts but I would like to add a little more.

Something I caught in your first post is you bypassed the transmission cooling loop in the radiator when you installed the aux cooler. This is a bad idea. Oil / air heat exchangers (like an aux trans cooler) are not terribly effecient, especially when there is not much airflow over them, like when you are climbing a steep hill or backing into a campsite. Without active cooling the trans fluid heats up in a hurry. The oil / water heat exchanger in the radiator is very efficent and works even if the car is not moving. The coolant in the radiater is a pretty big heat sink and will take a lot of heat from the trans fluid before it starts to get too hot. You really should run the loop in the radiator and the aux cooler in series. I had a 2004 Explorer V8 and towed my 5200lb loaded trailer (similar to your trailer) with it. Explorer was rated for 7000lbs and I was within all specs. It had the radiator loop deleted at the factory and just used a stacked plate air cooler. Twice after towing home fluid overheated and leaked past the front seal while I was backing into my space. It also went into protection mode more than once where shifts were very firm going up slow hills. I would have had to do something if I had kept the Explorer.

I currently have a similar setup to you, my 2007 Expedition EL 5.4 has 300hp and 385ftlbs torque with a 6spd transmission. My experience is same as you describe When towing up significant grades especially at elevation I definately slow down to 40-45 and be in 2nd or maybe 3rd. I do not have tow haul mode, so I often will manualy gear down before the transmission wants to and hold the gear as long as necessary keeping the engine at 4000-4500 rpm. I always lift off the throttle when I shift down. OHC engines make power at higher rpm and are designed to run there. For those who have been around awhile and are used to old big blocks this is the opposite experience. While a big block may be close to blowing up, a OHC engine is just getting warmed up at 4000. Higher rpm will usually keep the torque converter locked, it will also run the water pump faster and if you have an engine powered cooling fan (I do) it will run faster too. It is better to go a few mph slower with the engine rpm up than to go a little faster with the engine rpm lower.

Here in SoCal I have to climb a mountain to go just about anywhere. I have towed over everything from mild to moderate interstate grades, more significant secondary highway grades, and some steep mountain road grades that had me in 1st. I have been satisfied with the Expedition's towing performance and love it for people / stuff hauling the rest of the time I am not towing. Would I love a new ecoboost Expedition? Heck yes, but I am really enjoying NOT having a car payment!

[time2roll]

boggerr wrote:
LS swap the Armada lol

Yes an old LS-7 should have the OP passing everyone :B