Hello guys, as the posting suggests, I am curious as to ideas that you guys have for a 5.9 Towing Build. My goal is not necessarily peak hp. And I certainly don't give a crap what hp the engine makes at 5000 rpm because I'm never going to drive at that range. The max I go when Towing is 4k rpm maybe 4.5k rpm for merging onto the freeway. Reliability is always my priority. I want an engine that I can hold my foot on the floor for 5 minutes straight while climbing a 6% grade. I can confidently do that in my currently stock 5.2 magnum. The engine makes good enough power to tow 5000 lbs on mountains, 6,500lbs on flat land. but I am here to ask how much more torque can you get out of a 5.9 in the 2500-4000rpm range and what type of Build would I need for that? I'm assuming aluminum heads, high compression ratio, maybe some headers, and a tune/carb obviously.

My reason for posting is that i want to know how much RELIABLE, TOWABLE, 100% DUTY CYCLE power/torque figures can you get out of a 5.9 Build. And is it possible to get those figures in the 2.5k - 4k rpm range? And if so what parts do I need?

my goal would be to have 400lb-ft of torque at 3000rpm. Maybe even lower if possible?? That's only about 228hp if you do the math. If i can hold 400lb-ft all the way up to 4000rpm that's 305 hp. So I'm not asking for crazy racetrack figures. I just want to know how much real usable power i can make while still being dependable and not fragile.

And as a secondary question for those who know tuning. Do you think there is a setup which will allow me to make that sort of power in the power band mentioned, while still being able to utilize the high compression ratio to get better than stock fuel economy when im off the power just daily driving? I know im asking for alot. I just never hear anyone mentioned efficiency in daily driving when talking about engine builds. I don't want to bother putting together an engine like this if I'm going to get 10mpg city and maybe 16 on the highway. My stock 5.2 gets 16/19 city/highway. I'll keep my stock power before I get worse efficiency.

Let me hear your thoughts please

 

I see you are in CA, Do you have emissions testing? If you do that would have to go into the build.

 

You also mentioned higher compression. Do this mean that you're willing to step into the premium fuel category? I ask, as my goal is to stay with regular fuel and still achieve the best results possible...

 

Cam, better heads, free flowing exhaust, and a custom tune..... California emissions is going to complicate matters though.

 

Thanks for the fast responses guys, as far as california emissions go, I'm not too worried. I'm only stationed here for the moment, that won't be the case once I actually get around to this build, but my home state is Texas and that's where my vehicles are registered.

As far as premium fuel, yes that is something im willing to accept because from my limited tuning knowledge the higher octane will allow me to run higher temps, and leaner fuel without knock, which when paired with high compression, im hoping that is the winning combo for an engine that can deliver above stock power when I'm heavy on the throttle, while delivering above stock fuel economy when I'm off the power. That's the idea at least.

 

Is the truck you plan to install this motor in a 1500 (1/2 ton) or a 2500 (3/4 ton) truck? Also, is the truck 4x4? I ask, as you will likely be hard pressed to attain great fuel mileage that you're experiencing now with your 5.2 engine with a 5.9 engine all while building for great torque numbers. You might also consider a stroker engine (ie: 5.9 engine with a stroker crank = 408 engine) to achieve your goals, but fuel mileage will also suffer.

 

Hello, it's a 1500 single cab, short bed, 2wd mannual. It's already the best possible configuration for fuel efficiency and it's still subpar at best. So if adding power will make daily driving even worse. I'll just stick with my little 5.2.

as far as a stroker kit, I feel like at that point i should just go diesel. I'm pretty much trowing fuel efficiency in the trash at that point. My main attraction for gas engines is they're ease of maintenance and relative robustness, I can fix a carburetor on the side of the road, or replace a spark plug, distributor, etc. but if an injection pump explodes on me that's it. I'm not replacing an injector on the side of the road. Maybe that's a conversation for another thread, maybe I just have a fear of being stranded on the side of the road for the hundredth time lol.

 

I'm new here so let me know if I'm allowed to do this or not, but as I am in a similar boat planning for a future build, I recommend checking out Utawsome Performance. Marty is a mopar performance veteran and has done many mods to improve these trucks including fine tuned the kegger intake manifold for max torque powerband with some horsepower increase which is sort of tunable based on what you want. He's figured out the high rpm/high horsepower intake manifolds kill low rpm torque so he's improved the OEM kegger intake for better towing and such. He's got a ton of free info on his website on things he's done and dyno results. Although he doesn't talk about numbers with gas mileage he does have a section where he talks about some things to do for mpg improvement including air/oil separator and his plenum hot oil shield which reduces intake air temps. His personal truck is a 5.9 V8 which is setup for recreation and pulling his camper trailer. I'd check out his website, he's got a wide range of good info for performance mods for these trucks. Hopefully that will help a bit!

 

I think the throttle body and kegger mod plus upgrading the exhaust(headers/duel exhaust, X pipe) with a good tune would be a definite improvement. If it's still not what you are after you can upgrade the internals(or go with a 5.9) at a later point. Better breathing is always a good start.

 

Thanks guys, ill for sure be looking into those mods that were mentioned. And it sounds like that website has alot of good info. I guess i just have to make the decision on wether or not to go down the 5.2 rabbit hole, the 5.9 rabbit hole, or the diesel swap rabbit hole 😂