5.3 or 5.9 magnum in TJ?

[miyvh7]

I am looking for real world input from anyone currently running a Dodge 2001 or newer 5.2 or 5.9 magnum, NV 3550 or AX-15 trans in their rig. Specifically I'm looking for info on the power and gearing selections you made to run 33" –35” tires such as seat of the pants HP / torque, shift points RPM and fuel mileage. I have a 2001 TJ Sport 4.0L AX-15 5 spd D44 & 3.73 on 33's with 15" rims, no lift yet though. This is my DD and will remain so. I plan on adding equipment and pull a trailer for "Base camp" expeditionary/overland type camping and wheeling. Total GVW would be appox 5,200 lbs with trailer weight of appox 2,000 lbs. I have been considering power upgrades to the stock 4.0L or a 5.2 / 5.9 magnum swap to reach 300 hp / 300 lbs torque. Any help would be appreciated.
Thanks in advance
Upaded to correcct the 318 to liter conversion

 

[Desert Dan]

Are you talking about modifying your TJ?

I would consider a TJ or JK Unlimited if you plan on towing. The longer wheelbase will help more than a V8.

 

[miyvh7]

Yes, This would be a project build for the wife and me to travel and see some of our countries wilder places. While the LWB would provide some enhanced characteristics while towing, a smaller portion of the total normal usage, the basic problem still remains, i e insufficient power and torque. The LWB did not inspire the same passion for us so the LWB / SWB tradeoff against still having the address the same problems did not make sense.

 

[Xjaddiction]

Above makes sense, but if your keeping the TJ short WB, then stretch it a bit, the wheelbase that is. If your staying with stock axles, if you've got that dana35 get rid of it, go 8.8 or dana 44. The front change to an HP 30, then regear the axles... depending on tire size. I would looke into a tranny swap and eventually upgrading your 231 t-case to a HD version with slip yoke... Your really openning a can of worms at 35" tires. Your axles, suspension, steering, brakes, will all have to be upgraded to have a dd trail rig. I don't know what your budget or time schedule is, but on the cheap (and it still isn't that cheap), this is what I would do...

-change the rear out to a Ford 8.8 with the disc brakes out of a '95 up explorer, the front to a HP dana 30 out of a little cherokee.
- The HP 30 would add the warn hub kit, chromo axles, 760 joints
-tires 33's with 3.5" back spaced 15x8 or 15x10" wheels, adds width and stability
-Regear to at least 4:88, your Jeep has 4:10's now
-stretch the wheelbase an inch or two
-cold air intake, and exhaust upgrade, HF cat, free flowing mufler. That engine is plenty strong enough to handle that weight, and trailer tow 2G's
- do a low lift, run tube front fenders, and cut the rears and add steel flares. Low CG is important for a dd and trail rig, especially towing
-run some adjustable shocks like the Rancho 9000 to set your load and towing abilities to max. control
-sway bar dc's or better the currie sway bar set-up
-Currie steering minimum, or an OTK set-up with ton TRE's
-extended brake lines, upgrade rotors, and pads at least...

An engine upgrade like a 5.9 is expensive, and I really don't think necessary for towing 2G's...

If your set on an engine swap, call the Nashville, TN 4 Wheel Parts store on Nollensville road, and ask for Sam. Only Sam there... He's done a bunch of engine swaps, including a 5.9L into a TJ. He can give you an idea if 1- it's worth doing 2- The cost.

 

[miyvh7]

Thanks for the quick reply and since I see that you are already running a 5.9 your input will be greatly appreciated.
The purpose of this vehicle is primarily long distance vehicle dependent travel, in North America. Much of that travel will be on paved roads, and will be pulling a 2,000 lb travel trailer on road but also providing off road trail capability of 3.5 or greater with no additional modifications when completed. All modifications will have the appearance of a “Factory Option” and provide 100K reliability. As such a high fender mod such as offered by AEV might be a consideration.
The starting point as noted above is a 2001 TJ Sport 4.0L AX-15 5 spd D44 rear & 3.73 on 33's with 15" rims, no lift yet though. My build plan to date is as follows

Stage One, Platform. To establish the basic platform on which subsequent stages will build
Stage Two, Livability. The interior NVH, seating, navigation, electrical support and storage systems
Stage Three, Drive Line Power. Achieving 300 HP / 300 Lbs torque assuming a parasitic driveline loss of 30% to the rear wheels

Stage One will consist of: Suspension, Axles / Gearing, Fuel and armor
Build Parameters: Utilizing the least amount of lift required to accommodate a maximum of 35" tires, and comfortably tackle trails with an nominal trail rating of 3.5.
· Lift 3.5” max capable of supporting V-8 upgrade if required, Potential GVR 5200 Lbs.
· D30 / D44 / D30HP front, Disk conversion rear
· Custom bumpers front & rear (Nate’s front, AEV JK patterned Rear including tire carrier) 8000lb + wench in bumper lights front & rear
· 4.56 / 5.13 part time locker (on road RPM @ 75mph 2400)
· 350+ mile range
· Armor to provide complete underbody obstacle protection and additional ground clearance for 3.5 class trails, 24” obstacles

Stage Two
· NVH, Noise Insulation of body and top for heat and noise
o Vibration control, suspension, engine and driveline mounting to minimize.
o Handling to maintain original OEM performance characteristics
o Reclining long distance adjustable (Corbeau GRS II)
o Electrical power for off road lighting, interior outlets for multiple dc connections, 1000 watt dc/ac inverter
o Overland travel gear, water storage & dc fridge

Stage Three
o V-8 swap 2001 - 2003 5.2 – 5.9 magnum to utilize factory cpu, wiring harness and drive line. (Magnum V-8 into a TJ Wrangler file) o
Any help you can provide in avoiding mistakes and achieving the stated goals though “lessons learned"

 

[Xjaddiction]

Sounds like you have the budget, and are on the right track. Give Sam a call

(800) 257-5642

and he can give you an idea about cost and what the Jeep runs like with it. You will need stronger axles with the V-8. I would look at rock-jock or any HP 60 app. Your 44 and a switch to the HP 30 will get you through for now... 'till the v-8 swap.

My 5.9L grand has 3:73's and a 4 speed OD Tranny with the part-time 231 HD Tereflex case. The power is fantastic. I also have a ford 7.3L diesel. The Jeep tows my 6000lb boat out of our Marina just as well as the Ford. Very steap long up-hill climb out.

 

[ccarley]

I just have a few suggestions as far as the towing is concerned.

As has been mentioned, long wheelbase will be better. Also, the stronger axles will help, as you will be exerting a lot of torque while driving with the trailer. Also don't forget about your brakes, as well as trailer brakes. Having a trailer brake controller installed is important for a trailer that size, IMO.

While considering suspension, again as mentioned adjustable shocks are probably the way to go. I would also consider installing airbags in the rear, to assist with the load while towing. If you are going to use load bars with the trailer (highly recommended, but adds a lot of weight), they are not as high on the list, but if you don't use the load bars, the tongue weight will really push the rear down causing sag and possibly reducing the life of your coils. I used to work at an RV shop, and one of the complaints after upgrading suspension (sans shocks) was that it was "wallowy" while driving with the trailer; having adjustable shocks can cure that feeling.

Using airbags tee'd together in the rear will help keep the load leveled, as well as keeping flexability for off-road. Add pressure to level the vehicle, and then remove it (down to 20 psi anyway) to level it again when unloaded.

Good luck with your build!

 

[miyvh7]

Thanks and the brake upgrade goes without saying. The front mounting point for the disc tend to deflect under the higher loading that this setup will impose, so when the front axle is addressed these will be part of the upgrade as well. As for the “load leveling” aspects of the air bags I have used these on other rigs for towing but have not heard of them being utilized on trail rigs. Any thoughts on pinching of either the bag, mounted inside the coil, or the air lines here?

 

[ccarley]

I think Firestone actually makes airbags designed to run inside the coil. The only catch is that you have to run at least 15 or 20 psi (I can't really remember) so that the bag doesn't pinch inside the coil. If it goes flat, the bag will pinch. If there is pressure, they don't pinch. The rubber they use is pretty tough stuff; basically similar to what is used for tractor-trailer rear suspension. The air lines are 1/4" plastic tube rated at a very high pressure. The fittings are easy to work with, so even if you did somehow catch an airline, they are easy to replace. The fittings come out of the tops of the bags, and the lines are usually run inside the framerails to an access point or to inside the cab, if you go for the control panel you can get.

I'm also considering a set for the rear of my Grand Wagoneer. I like when it sits level, but if it's level when unloaded, it sags when it's loaded.

I think the "scorpion" buggy from "back in the day" used all air-bags for it's suspension...

 

[miyvh7]

And then lies the problem in that you apparently must maintain pressure in the bag at all times. While this is not a problem on the road, the highest percentage of use, the off road capability to manage 3.5 rated trails may pose a problem in that the bag will need to be deflated to allow the suspension to work at full capability.

 

[miyvh7]

Getting back to the reason for this thread Xjaddiction that is a very capable rig. What type of performance are you seeing, seat of the pants HP/ Torque, fuel range, I know auto v manual but a base line would be helpful, RPM as 75 etc.

 

[computeruser]

+1 on the airbags. I've got them in my TJ, and they have worked nicely, flexing more than enough for the sort of terrain I cover. 5psi is the minimum that AirLift requires to keep the bags in place within the coil spring; I run 7-9psi around town, 10-15psi off-road depending on terrain, and 15psi with the trailer on. Works wonders.

I agree yet disagree about the wheelbase issue. We're talking about a 2000lb trailer driven by a mature, sensible adult. Yes, it'll work the Jeep a bit more, but nothing that creates a grave risk to vehicle occupants or others. You have to get closer to 3000lbs to start having handling issues with the short wheelbase, based upon my experience towing trailers loaded with logs, dirt, gravel, and other things that TJs probably shouldn't tow.

 

[miyvh7]

Thanks, it's interesting the you run increased PSI off road, 10 – 15, I would have ***-u-me d, and you what happens when you do that, that the opposite would have been the result to take advantage of the suspension articulation. Can you help me understand why the inverse is the case?

 

[Lumberjack]

Just a note, a TJ on 33's will cover plenty of 4+ trails without the extra height required for 35's. If you kept it lower it will be nicer as a daily driver and most likely tow a little more comfortable. I have gone back to 33's and enjoy it better... my tj is also stretched 15"... I go everywhere I did on 36's, just need to choose my lines a little better.

A 318 is in the future, geared with 4.56's and some sort of base camp trailer.

Dennis

Also lookup Backwoods Offroad, Evan sells wiring harness and other parts for the swap.

 

[miyvh7]

Thanks I will follow with them. As for the tire size, I tend to agree but wanted to look at the capability with the suspension mods if the extra size was required. Sounds like all that is really required is a better-qualified operator and less cash.