kj could use some umph while towing

[Mr.Jack]

I pull a 2000lb (loaded) enclosed snowmobile trailer in winter,and a 3750lb pup trailer in summer.With either trailer it seems the kj just doesn't have the muscle.Especially up hills.I've been told to install a chip,cold air intake, and a fuel body spacer.Any thoughts on this matter?

 

[MoladoGuy]

Here is a write up from Dave who had no major issues towing this camper (2500/3500 loaded). What is your current tow setup (brake controller, class III hitch, upgrade brakes on KJ, etc...)

http://www.jeepkj.com/forum/showthread.php?t=33450&highlight=Towing

 

[KeswickDave]

Oooh I've been quoted, I think that's a first!

My only "performance" related mods are a Flowmaster 50 SUV muffler and Amsoil drop-in air filter.

Yes, I would love more power for towing, don't get me wrong, but I felt given the weight and frontal area of my trailer, that it pulled it adequately. But this is a pretty subjective area and what one person feels is adequate another may not.

Are you running with overdrive off? That could make a difference in percieved power.

Dave

 

[JeepJeepster]

Im surprised that you even notice the 2k trailer, thats not much at all.

The 3500 trailer is pushing the limits of the KJ IMHO. I know 5k is the MAX rating, but I would never go over 4k with mine given the type of terrain I live in(alot of hills and mountains).

Those mods you listed will probably net around -5HP(yes, negative).

Best thing you can do is to get a shift kit, K&N or Amsoil drop in filter, and a free flowing exhaust.

 

[Mr.Jack]

My current set-up is the class III hitch it came with,heavy duty alt.,Equalizer 4 point sway and weight distribution,and brake controller.******/oil cooler.I always run with the O/D off while towing.I still run the stock brakes.Handling has been awesome.Just the power issues are my concern.The 2000lb feels way heavier than the 3500lb.I guess it has to do with the wind drag .The pup trailer sets slightly lower than the kj.I live and play in the mountains.So,there are some big hills.Thank you for the responses so far!

 

[SoDakJeep]

wind drag kills everything.....

 

[J-Thompson]

I have not noticed a problem towing with the KJ until the 245/75's
it pulled my brothers YJ on 35" super swampers with ease ,flat tow about 4200#
stoping was another story
lots of factors but gearing is #1 as far as pulling power goes

 

[desertkj]

Do not install the chip or the spacer. I have heard more stories of people actually losing power from those on the KJ.

 

[KJ2005]

compromises

I sold a fullsize truck and bought a KJ to get alittle improvement in gas, but also go offroad in a few places the truck couldn't. I'm happy with the sacrifice because I don't haul alot and rarely trailered.

You have to figure the compromises of a KJ:

For it's size the KJ is heavy

not as bad as the power to weight of a hummer H3 but it's heavy.

It's also a 3.7L v6 and a unibody chassis so the power and solid frame just aren't going to be there for a trailer that's as large as the vechicle itself.

I had a small tool box, full tank of gas and a mini cooler to go off road and the stock springs sagged enough to eat 245/70/16 tires at the rear, which shows they aren't very stiff.

with the narrow track and wheel base I'd think the heavy trailer would also start to sway the jeep like it would a reg cab mid size truck.

all in all the jeep KJ to me is what an entry level SUV "crossover" should be defined as: capable of doing alot of tasks well, hauling family in relative comfort, going off road, and trailering, but not able to do the best job at any of them without some serious modifications directed to the task of choice.

 

[Mr.Jack]

what exactly would a shift kit do in this case?

 

[JeepJeepster]

Firm up the shifts in the ****** to reduce wear and tear along with heat.

Got to remember, there is alot of torque added to the drivetrain when towing.

 

[tjkj2002]

Got to remember, there is alot of torque added to the drivetrain when towing.

There is zero additional torque added when towing(as far as the drive line is concerned,now the added torsional stress to the unibody is a different thing),unless you add a turbo,supercharger,and such.There is however added stress to the driveline.

 

[JeepJeepster]

Are you kidding me tjkj? How do you think pulling 5klbs doesnt put more torque on the drivetrain than just driving around in the city?

 

[Ry' N Jen]

There is zero additional torque added when towing(as far as the drive line is concerned,now the added torsional stress to the unibody is a different thing),unless you add a turbo,supercharger,and such.There is however added stress to the driveline.

Torsional stress? Isn't that pretty much the same as torque only in an other applied mathematical equation?

 

[JeepJeepster]

Idk any other kind of stress you can put on the driveline other than torque. I know it doesnt go sideways.

 

[tjkj2002]

Are you kidding me tjkj? How do you think pulling 5klbs doesnt put more torque on the drivetrain than just driving around in the city?

Your engine is putting out the same torque # from the engine empty or pulling 5000lbs,you don't get free torque out of the clear blue sky.The "torque" you are referring to is torsional stress(key word is "stress"),the effects of adding wieght and trying to go,that has nothing to do with what the engines torque output is(though more torque from the engine = more "stress",but you need more torque for that,just throwing a trailer on your engine doesn't automatically add torque from the engine).

Torsional stress? Isn't that pretty much the same as torque only in an other applied mathematical equation?

Torsional stress is the effects of torque on the unibody,and the added wieght of the trailer.Again you can't gain additional torque from your engine unless you put a power adder on.

Let's say the 3.7 puts out a max of 235 ft-lbs of torque at 4000rpm,well at 4000rpm your engine is putting out 235 ft-lbs of torque if your towing or not.

 

[tjkj2002]

Idk any other kind of stress you can put on the driveline other than torque. I know it doesnt go sideways.

"Torque" is not a stress,torque is a power in the form of a twisting motion."Torsional stress" is the stress caused by torque,two seperate words and meanings,torque is often misused.

 

[Ry' N Jen]

Thank you tjkj for clarifying this.

Cheers

Ry'

 

[JeepJeepster]

If you say so..

Do you put more stress on the drivetrain when offroad? Or is it just a coincidence that you break ujoints and drivelines when offorad? Remember, that engine can only put out 235ft lbs of torque.

 

[J-Thompson]

If you say so..

Do you put more stress on the drivetrain when offroad? Or is it just a coincidence that you break ujoints and drivelines when offorad? Remember, that engine can only put out 235ft lbs of torque.

well if you realy get down to it
99.9% of the time you can not break any part of your drive "line" from to much power
I have seen SEVERAL different things break out on the trails most of them being U-joints and axel shafts but the one common factor was not to much power but shock load

Look at it like a coke can
you can stand on it ,open end up, and not bend it but you can drop a 1/2#
weight on it and it will bend ,shock load VS "easy load"

Think about it
even the "weak" front diff. in a KJ holds up just fine until you shock load it