Advise Needed

[Trouble1233]

My first 2019 was a 3.92, it was returned to the dealer three weeks later and my new Laramie is a 3.21. To be honest, I don’t feel a real difference at all. So, my opinion, if you find what you want with the 3.21, go for it. It’s not as detrimental as it was in the JK with bigger tires, etc., because the Hemi has plenty of power and torque. I’m satisfied.

Why did you return yours if you don’t mind me asking


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[Trouble1233]

Do either of the trucks have E-torque? That might be a more important factor than you realize.

E-torque = auto stop/start. If you're sitting at lights a lot, that could make a difference on fuel mileage. Some dislike auto start/stop (myself included), but the Ram doesn't use the normal starter motor for this, so it's supposedly more seamless.
E-torque also has more off the line power according to FCA. I've never driven a truck with it, so I can't say from personal experience. That said, I have to wonder how quick if the truck has shut off and has to restart.

Again, I have never driven one myself, but it is something to consider if only one of the trucks has it.

I got the etorque and I can tell ya this..I pulled a 24ft trailer right at 8800 lbs and it does help get it moving fast..and I like the way the stop and start is seamless..now if I had my choice I wouldn’t have the stop and start but you get use to it..mine has the airride 392 gears


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[Trouble1233]

My 2019 Laramie has the eTorque Hemi engine. Been living with it for a little over a year now. I have a buddy with a 2018 and he actually gets 2mpg better fuel economy than I do.

Don't get me wrong, we love this truck... But don't let eTorque be a selling point. After living with one for a little over a year, I can tell you that the only thing eTorque buys you is start/stop. The fuel mileage savings is all smoke and mirrors. Nothing to see...

It helps towing though


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[Fmrchvy]

Why did you return yours if you don’t mind me asking


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Worst dealership story ever, Marshall CDR in Northern Kentucky, sold me a black edition Ram and said they could add the LED Light Package. Once the time came, I made sure it was on the ‘We Owe’ sticker, then they tried to plug in cheap LED Bulbs after charging me over $900 for the package. Then, to take the cake, they sprayed bedliner all over the rear of the truck, scratched the bedside and the estimate to repair was over $2k. I demanded a buy-back and they voided the deal. A few weeks later I found my Laramie for nearly the same price as that Big Horn at another dealership. It all worked out in the end.

 

[TWRam]

the only actual problem with the 3.92, in a practical sense, is lower mileage.

My new truck also has a 3.92 rear end (and a Hemi w/E-torque) and I really wish I had gotten the 3.21 gears. I do a lot of highway driving with the cruise set at 80 MPH. At 80, I'm turning around 2200 RPMs, where I get terrible fuel economy.

I think you may be surprised if someone was to do a relative and repeatable fuel economy test with 2 identical trucks with the exception that one has a 3.21 rear end vs the other with a 3.92 rear end. At 80MPH, your truck is fighting a huge amount of aerodynamic drag. It takes the same amount of energy to move your truck through the air at those speeds, regardless of what rear end is pushing it. Energy is created by fuel. With the 3.21, you'd be turning 1800 RPM vs 2200 RPM with the 3.92. The difference in friction from the rotating assembly between those 2 RPMs would be negligible. The only other significant contributing factor would be engine efficiency vs RPM vs throttle position. Is the 5.7 Hemi engine significantly more efficient at 1800 RPM than 2200? I'd say no. It may be a common misconception, but lower RPM does not always mean better fuel economy, and in this case, there may not be a substantial difference in fuel economy at 80MPH at 2200RPM vs 1800. My guess would be less than 0.5 MPG difference.

Thinking through this some more, there is an easy way to test this theory on a truck with a 3.21 rear end. There is a 25% difference in the ratio of 8th gear vs 7th gear. 7th gear on a truck with a 3.21 rear is very similar to a truck with a 3.92 rear in 8th gear. While cruising at 80MPH, monitor your MPG on a flat stretch of road, then shift to 7th while maintaining 80 and observe the difference. I'd be interested in knowing what the difference is. I'm sure some others would as well. Anyone out there with a 3.21 rear willing to do the test? It might help some of us sleep better at night knowing that we're not missing out on much of a FE improvement........or not depending on the results.

I may try it out, but it will be like going from a 3.92 to a 4.90

 

[Trouble1233]

Worst dealership story ever, Marshall CDR in Northern Kentucky, sold me a black edition Ram and said they could add the LED Light Package. Once the time came, I made sure it was on the ‘We Owe’ sticker, then they tried to plug in cheap LED Bulbs after charging me over $900 for the package. Then, to take the cake, they sprayed bedliner all over the rear of the truck, scratched the bedside and the estimate to repair was over $2k. I demanded a buy-back and they voided the deal. A few weeks later I found my Laramie for nearly the same price as that Big Horn at another dealership. It all worked out in the end.

Dude I don’t play well with people like that..


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[StuartV]

Is the 5.7 Hemi engine significantly more efficient at 1800 RPM than 2200? I'd say no. It may be a common misconception, but lower RPM does not always mean better fuel economy, and in this case, there may not be a substantial difference in fuel economy at 80MPH at 2200RPM vs 1800. My guess would be less than 0.5 MPG difference.

Agree with all of that - except that my suspicion is the difference in efficiency between 1800 and 2200 would result in a bigger difference than 0.5 MPG.

But, I definitely like the idea of the test you proposed. We just need a 3.21 guinea pig.

That said, I stand by my earlier post, that 3.92 vs 3.21 makes no difference in takeoff from a stop - IF you are not towing/hauling. Since I don't really tow anything or haul anything heavy enough to really matter, I still would have rather gotten the 3.21 rear end and had the better mileage - even if it's only 0.5 MPG.

 

[Adrianp89]

I can confirm the 1800 vs 2200. Not exact but my old truck (2013 8spd) ran around 1800 and now my new truck with 3.92s runs around 2100/2200. With that being said - my instant meter is about 5-7 mpg lower.

 

[kstod21]

I think you may be surprised if someone was to do a relative and repeatable fuel economy test with 2 identical trucks with the exception that one has a 3.21 rear end vs the other with a 3.92 rear end. At 80MPH, your truck is fighting a huge amount of aerodynamic drag. It takes the same amount of energy to move your truck through the air at those speeds, regardless of what rear end is pushing it. Energy is created by fuel. With the 3.21, you'd be turning 1800 RPM vs 2200 RPM with the 3.92. The difference in friction from the rotating assembly between those 2 RPMs would be negligible. The only other significant contributing factor would be engine efficiency vs RPM vs throttle position. Is the 5.7 Hemi engine significantly more efficient at 1800 RPM than 2200? I'd say no. It may be a common misconception, but lower RPM does not always mean better fuel economy, and in this case, there may not be a substantial difference in fuel economy at 80MPH at 2200RPM vs 1800. My guess would be less than 0.5 MPG difference.

Thinking through this some more, there is an easy way to test this theory on a truck with a 3.21 rear end. There is a 25% difference in the ratio of 8th gear vs 7th gear. 7th gear on a truck with a 3.21 rear is very similar to a truck with a 3.92 rear in 8th gear. While cruising at 80MPH, monitor your MPG on a flat stretch of road, then shift to 7th while maintaining 80 and observe the difference. I'd be interested in knowing what the difference is. I'm sure some others would as well. Anyone out there with a 3.21 rear willing to do the test? It might help some of us sleep better at night knowing that we're not missing out on much of a FE improvement........or not depending on the results.

I may try it out, but it will be like going from a 3.92 to a 4.90

I know this is anecdotal but I rented a 2019 Big Horn in April (5.7 Hemi, 4x4) with a 3.21 and was getting around 22mpg for the whole weekend I had it after about 400 miles (city and highway). I've had my 2020 1500 Limited for about 2 weeks and I've been getting around 13 now. The only differences are my limited has the off-road package, 3.92 and I also have the eTorque. I don't get it. Shouldn't be such a drastic difference.