My wife and I are looking at buying a new truck, and it is going to be a 2009 or newer Dodge Ram. It will for sure be a 4x4 SLT Quad or Crew. The engine is where I am stuck. It is winter here so it is hard to test drive one and hammer on it without putting it in the ditch. It is also hard to drive it long distances and see the fuel economy. I see that the 4.7 is rated at 310 hp and the Hemi at 390 hp. At most we will haul a 16' or 18' toy hauler with 2 Can-Am Outlanders. I assume that either truck would handle the job, but would the 5.7 outperform it by a large margin? What is the 0-60 on either truck? Does the 4.7 have enough power for what I need? It looks like the 4.7 is comparable to the Ford 5.4 and the Chevy 5.2 hp-wise. We can get a 2009 4.7 for $20000ish, a 2010 4.7 for $22000ish, and a 2009 5.7 for $24000ish. The 2010 will have a transferable 5 year/100000 mile warranty, vs. the 3 year/36000 warranty on the 2009, but I don't anticipate any powertrain problems. If you were in my shoes, and you were tight on cash, would you fork out the extra $$$ for the Hemi, and if so why. Please give me any and all feedback. Thanks in advance for your time.

 

I can tell you that I had a 4.7 275hp 3.92 gears in my 05 Dak which weighed only 500lbs less than my Ram 5.7 hemi. The Dak towed a 4200lb RV fine except for 25 mph+ headwinds and long 6% grades where it had to downshift to 2nd gear to maintain 55mph. I put 4.10 gears in it and it did a lot better but still a struggle under those conditions.

Some of the 4.7 Ram guys will weigh in with their 310hp experience. I've read that it does fairly well.

 

The decision for me really came down to net cost difference and gas mileage estimates. When I bought the Hemi trucks had a 'free Hemi' option. Even if that wasn't available I would still have opted for the 5.7L because the mileage difference is about 1 mpg between the two and MSRP diff was about $1500. Why give up the power, capability and fun factor for that minor of a difference?

As for your examples, there must be something else different between the two 2009 models because the Hemi alone would not cause one truck to be worth $4000 more than the other.

Ultimately if cash is the biggest consideration then you have to go with which one works for your budget. If you must choose the 4.7 I don't think you will have made a 'bad choice'. It's a good engine too. It's just no Hemi. Those 80HP will make a difference in a vehicle this heavy. Maybe not a 'can't do it' difference, but definitely a 'how hard will it work and how comfortable can it do it' difference.

Rob

 

0-60 in a 4x4 Crew Cab ST 4x4 with 4.7L 3.55 and 17's is 9.9 Seconds
0-60 in a 4x4 Crew Cab SLT 4x4 with 5.7L 3.92 and 17's is 6.6 seconds
Those are not from the same source and so cant be directly compared.
My guess is same day and same gear about 2.0 seconds difference.

I own a truck like the first one. I dont think you would like the 4.7L 3.55 Combo for Towing. Even empty it will lose 3-4 mph on moderate hills then downshift from 6th (Indicator numbers gears from 1-6) to 4th bypassing 5th. It also will not upshift to 6th until 55 mph (56 mph indicated).

It maintains speed fine if I limit top gear to 5th which makes me think this wouldnt be an issue with the 3.92. A 3.55 has almost the same overall ratio in 5th as a 3.92 in 6th. 3.55 x 0.75 = 2.66, 3.92 x 0.67 = 2.63.

i believe the Hemi is actually rated at better MPG due to the Variable Valve Timing and Multi Displacement System. In the real world Ive yet to see a Hemi average the 19.0 mpg in mixed driving my 4.7L does. But then most dont equal my fuel mileage.

Overall I would not recommend a 4.7L unless it came with a 3.92 Gear and 17's where as the Hemi might be fine with 3.55 and 17's. I think I would still want 3.92 with the Hemi if it had 20's.

 

If you plan to tow often I'd definitely recommend the 3.92 gears no matter what engine you opt for, just better in the end if you ask me. The 3.21 is simply too tall to do any regular towing over a few thousand pounds so you're left with 3.55 and 3.92. The 3.92 will have a negligible loss in highway MPG but you will get back some around town and so much more when towing. (We actually have the 3.21 diff but we sit on the open highway at 75-95mph quite often and do little towing, so this diff fits our needs the best).

As for engines, it should be noted that the 4.7 actually produces more power at the very low RPM's (below 2000). After that the Hemi eclipses it in every way.

In any case, I don't think the 4.7 will outperform the 5.7 in any real world performance test. There's no getting around the added torque and horsepower.

I have little knowledge of the current gen 4.7L engine (which is more powerful and also flex-fuel capable compared to the older 250hp 4.7L in the 2002 Ram we had). I'm not aware of the gearing we had in the older truck but I do know that going to Mammoth (which is what we use the truck for 90% of the time), usually we avereage 14mpg or so round trip, sometimes as low as 12mpg.

Driving our Hemi the same way, we typically see 15-16mpg as average and the lowest ever was in the 14's.

So that's a 2mpg improvement with the Hemi. However, the newer 4.7L will surely be more efficient. How much? I'm not sure.

My sentiments are to go with the Hemi. You're gonna get pretty crappy mileage anyway (it's a big, heavy truck with a V8, what do you expect?), and you're better off with more than enough power than not enough.

 

I agree with pretty much everyone above. The Hemi is the winner in every aspect. One thing that no one has mentioned above is resale value. It is hard to sale a full size truck with the lesser option for an engine. The Hemi boosts resale value right off the bat. Having owned both a 4.7L (2003) and my 5.7L (current 2008) I say go with the Hemi. The extra $$ at the time of purchase is worth it.

 

Only you can decide what you can afford, and want.

Get the best you can afford - you will be happier in the long run.

Any of them are really nice trucks!

 

I just got a 2009 4x4 with the 4.7 and last weeked I pulled my 20ft trailer with 4 quads , I hated it!! It struggles under load up any over pass . I also have a 2010 ram 2500 with the 5.7 I pull with it all the time and it is night and day better at pulling then the 4.7. The only reason I pulled the trigger on my 09 is it had less than 8k , procomp lift with tires and rims already and a great price , but now i am really second guessing my purchase. Also I am sure my 4.7 would do better regeared , it has 35s with stock 3.55 gearing , and that doesnt help at all. Now i am looking at a regear job $$$$$, go with the 5.7 you wont regret it

 

Holy crap. 35" tires with 3.55 gears = effective ratio of 3.21. No wonder your 4.7 struggles. Even if you re-gear with 4.10's your effective ratio will be 3.70.

4.56 might be a better choice with those tires...effective ratio of 4.12

 

Yeah I'd definitely get 4.56 if I was him.