3.6 Engine - Now I understand the power issue

[Stan H]

This is a common misconception about diesels. People always hear how they make so much more torque, so they expect them to be lightening fast, but they aren't. It's a different type of power, different type of torque. It's all low rpm.

When I first bought my BMW X5 diesel I was expecting it to blow the doors off everything else. Off the line it would destroy almost anything... until about 40mph then it tapered off and was really no different that anything else in its class. Try to shit can it at 70 mph and it was ok at best, but roll a little into the throttle at 70mph and it would pull away hard because the rpms stayed low in the powerband.

Really gotta understand how to use diesel power and stay in its torque band. It's not like a gasser where the more skinny pedal the better.

drove tractor trailer all over the USA and that is exactly how it work

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[Zachanadandy]

Serously? 90? you want to go that fast in a jeep?

The post is a tad confusing - did you tow with the Grand Cherokee? Why the mention of it?
It's a very different vehicle, different gearing, tuning, and cooling. Might as well be a different engine in it.
So you were speed-shamed?

How fast do you go when towing?
I stick to 65, period (it used to be the speed limit for towing in many states)
Otherwise, I can easily cruise 85 or so in my JT - easily - no issues at all. My wife was driving my JT back from FL through the mountains in the SE - she loves to get home FAST, and was pushing the speed pretty hard in some spots. Never felt like it was a problem. Let it wind up.

I want to do 90+ in the dirt in my lifted Jeep and yes the 3.6L is barely adequate for that. Planning an LT4 swap when the powertrain warranty runs out. If 285hp is adequate, 550hp has got to be a blast. Of course if the 392 does make is way to the JT lineup it might just get traded in..

 

[Wheelin98TJ]

With a tune? Motortrend only managed a 15.9s 1/4 in the 3.0L EcoDiesel.

We were talking about the 3.0L Explorer. I should’ve been more clear.

 

[Jteakus]

I just spent a week in a Promaster loaded with parts and tools chasing down broken vehicles and repairing them. What the 3.6 lacks is low end torque. Any hill, vehicle pass or on ramp takes all the rpms. Not really ideal in a Jeep. But I got the diesel to cover it.

 

[Zachanadandy]

I just spent a week in a Promaster loaded with parts and tools chasing down broken vehicles and repairing them. What the 3.6 lacks is low end torque. Any hill, vehicle pass or on ramp takes all the rpms. Not really ideal in a Jeep. But I got the diesel to cover it.

Even in the heavy JT it's adequate on hills and passing on the freeway until you get above 5k feet.

 

[biodiesel]

My house sits at 4900' in the bottom of a valley, a bit more than Florida.

Those F150s aren't that heavy for a full-size and have turbos which dominate at elevation.

If you are a Ram diehard, the only towing answer at elevation is "Cummins".

As a diehard Ram/Jeep/Dodge/Chrysler fanboy, I love my 2015 Ram EcoDiesel, 2020 Ram EcoDiesel, and 2023 Jeep Gladiator EcoDiesel. Our property is at 7,100' feet. I do a lot of towing in the Mountain west. I agree that a turbo makes a world of difference at elevation.

 

[Jteakus]

@Zachanadandy
Do you have to rev it out? Apples to oranges comparison for sure but anytime I had to speed up tach was headed to the redline, I thought "What the heck, they built it. They must like it that way" Air box makes a heck of a growl R-ing out the engine.

 

[red/green hawk]

Serously? 90? you want to go that fast in a jeep?

The post is a tad confusing - did you tow with the Grand Cherokee? Why the mention of it?
It's a very different vehicle, different gearing, tuning, and cooling. Might as well be a different engine in it.
So you were speed-shamed?

How fast do you go when towing?
I stick to 65, period (it used to be the speed limit for towing in many states)
Otherwise, I can easily cruise 85 or so in my JT - easily - no issues at all. My wife was driving my JT back from FL through the mountains in the SE - she loves to get home FAST, and was pushing the speed pretty hard in some spots. Never felt like it was a problem. Let it wind up.

I drove this from Albuquerque to Lewiston, ID. Interstate from Provo all the way into Idaho to US 95 N. And not once was I lacking in any way, shape, or form. Yes those are chickens in the back. And sure there is not a lot of weight back there but my back seat was full of firearms/ammo among other things all the way to the top so it wasn't just me but I wasn't the most aerodynamic of vehicles out there either. 5 mph over the speed limit and hit the cruise all the way out there. It was a great drive, imo.

 

[Stan H]

I want to do 90+ in the dirt in my lifted Jeep and yes the 3.6L is barely adequate for that. Planning an LT4 swap when the powertrain warranty runs out. If 285hp is adequate, 550hp has got to be a blast. Of course if the 392 does make is way to the JT lineup it might just get traded in..

Oh boy

 

[JTGuy]

My 3.6 really came alive when I put in the 4.88s. Getting 15+ with the 37s.

 

[Stan H]

My 3.6 really came alive when I put in the 4.88s. Getting 15+ with the 37s.

I aint nostradamus but I already seeing shadowy images of gear sets dancing in my head and arriving under the Christmas tree

 

[biodiesel]

I need to do the swap myself. With too many irons in the fire, I have put it off. Now, at 175k miles, it's getting pushed closer to the front of the list.

Keep using a fuel additive and the CP4 pump will last a very long time. They have been shown to last 900,000+ miles with proper lubrication.

 

[Zachanadandy]

@Zachanadandy
Do you have to rev it out? Apples to oranges comparison for sure but anytime I had to speed up tach was headed to the redline, I thought "What the heck, they built it. They must like it that way" Air box makes a heck of a growl R-ing out the engine.

The thing makes peak hp at 6200rpm, you definitely have to get the rpms way up near redline.

 

[Flyin6]

Keep using a fuel additive and the CP4 pump will last a very long time. They have been shown to last 900,000+ miles with proper lubrication.

And lubrication is the exact issue with them.
Not sure if it is metallurgy or something else, but CP4 pumps installed in Chevys and Fords mostly failed the scar test when examined. 15ppm sulfur is not enough to provide sufficient lubrication. The diesel shops (3ea.) near me had shelves of CP4s they pulled due to issues, mainly in the Chevrolet and Ford platforms. In the Duramax community, the -4 pumps do not have a good reputation at all.
I added a quart of automatic transmission fluid to each fill-up, and I also strained and poured oil from the recent oil changes into the fuel tank. I drove my Duramax for a little over 10 years but most of the time it had a CP3 pump doing the heavy lifting.

 

[JTGuy]

With the 4.88s I find it hs plenty at 4K.

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