JK and TJ Engines

xGROMx

xGROMx

Dak and Wag
Joined
Aug 16, 2008
Location
The OBX, NC
I have been interested in Jeeps for a while now, while looking at a purchase.

This is to TJ and JK owners that have had or have both.

How do the new V6 JK's compare to the I6 TJ's?

I have been looking for a manual 4.0 but love the idea of a 4 door jeep. This will be a daily driver for a couple of years then a larger truck will be purchased to tow.

Late model TJ or Early JK?
 
the jk is SSSLLLLOOOOWWW compared to the TJ. I own a 6 speed jk , which are notably faster than the autos. but hey its a jeep not a race car.
 
there is also rumor of a Hemi option but who knows if that will ever happen...

check out www.jkowners.com for some good info and ask the question there. I know there are plenty of former TJ owners there that don't regret going to the JK. The 3.8 isnt that bad imo when it is geared correctly. I dont feel like I need a hemi but I wouldn't mind one either :lol:

you looking to buy a used?
 
Fart said:
The new engine beats the old one on HP and torque, right? So is it just weight that makes the difference?
Click to expand...
It's not just the HP/TQ numbers that makes the difference, but rather where you reach that peak TQ in the RPM range. The 3.8 only makes about 2 ft/lbs more torque than the 4.0, but does so about 1000rpm higher, where it is less beneficial to acceleration.
 
Fart said:
The new engine beats the old one on HP and torque, right? So is it just weight that makes the difference?
Click to expand...

well its all the electric governing done by the computer on bored. weight is another big factor.
 
Thanks guys, and WOW on the electric throttle, had no idea, and i'm not a fan of electronics on a jeep.

Jeep just needs to bit the bullet and make a "Jeep" again!
 
I've got a JK 4-door rubicon and a LJ (long wheelbase 05 TJ)

both 4 speed autos (JK 4.10 gears with 32s, LJ 3.73 gears with 31s)

The LJ with the 4.0 seems a little quicker and in mine the pedal is a little easier to apply (ie less resistance)

The JK is definitely slow, but I am never in a hurry anyway.

I can easily eak out 18 mpg city and 20+ highway in the JK

I can barely get 15mpg city and 18 highway in the LJ despite it being lighter.

these are both measured using a scangauge II
 
My preference is strongly towards the 4.0 due to reliability. I've have had several 4.0s last well over 200k miles with little to no issues. The same cannot be said for any other Chrysler engine I've had. That is why I won't buy a new wrangler.
 
I have both a 2011 4door JK sport auto w/3.73's otherwise stock. I also have from new a 2005 Rubicon Unlimited with intake/throttel spacer small lift and 285/75-16's otherwise its stock. I drove a new 4 door in 07 when they came out and felt they were really underpowered. It seemed very slow and sluggish. Even though I wanted a 4 door a couple years ago I resisted, hoping they would put a decent motor in them. Finally time came to replace a vehicle and my wife really wanted a 4 door. Having driven around 2600 miles now I can say that I have changed my mind about the minivan V6. I have made several trips to Boone up 421 as well as a good bit of highway miles and the motor has performed very well. No trouble accelerating to 75-80 , no trouble on 421 going into boone. I also have been averaging 17.8-18 mpg around town and about 20.5 on highway trips. I never get over 15 on the rubicon, both are autos. I would love to have a 6.1 hemi in the JK,but I haven't ever needed it.
 
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