There are lots of questions that come up from time to time on how to get more out of your TJ four banger. The short answer is: You really can't. The fours are what they are. Now before you head down to the local store to get a "for sale by owner" sign, let's consider what the four does well and what it doesn't do well.
First off, the fours are stone cold reliable. Properly maintained, they will outlast the rest of the drive train and body. 200,000 miles is easily achievable with normal maintenance. The fours are hammer simple. There just isn't a lot of moving parts in the four to go bad. The parts that do go bad are easy to change out and cheap to purchase. For that matter, a whole good used engine is easy to obtain and easy to swap out.
The fours have either 120 HP for the 2.5 or 140 HP for the 2.4 TJ engines. That is the power budget we have to work with. There is really nothing that you can do to either engine that will give you more power without messing up where the power band is or that doesn't cost more than it's worth. Even if you could get more power out of the fours, the next issue you would have to face is the transmissions that are hung on the back. You will scatter parts all over a trail with more HP under your right foot.
Now what does the four banger offer? The SE's are a thinking mans Jeep. They are small and light. They are simple, with few options to fail over time. They are easy to work on. The axles, Dana 30 and 35's, are perfectly adequate for the fours with a little upgrading. The transfer case is way stronger than it needs to be, so don't worry about that. The transmission is barely adequate, but it does work if used with a little discretion. It'll last a long, long time if you don't hammer on it.
When you go to modify your four cylinder TJ, don't start dreaming of 35" MT tires and huge lifts, body armor, meaty bumpers and huge winches. Just don't go there with the fours. Think 33" tires, with 32's being better and 31's being best. Think 1 to 2" of suspension lift and no more than 1 1/4" of body lift. Think light weight and simplicity everywhere.
More later...
First off, the fours are stone cold reliable. Properly maintained, they will outlast the rest of the drive train and body. 200,000 miles is easily achievable with normal maintenance. The fours are hammer simple. There just isn't a lot of moving parts in the four to go bad. The parts that do go bad are easy to change out and cheap to purchase. For that matter, a whole good used engine is easy to obtain and easy to swap out.
The fours have either 120 HP for the 2.5 or 140 HP for the 2.4 TJ engines. That is the power budget we have to work with. There is really nothing that you can do to either engine that will give you more power without messing up where the power band is or that doesn't cost more than it's worth. Even if you could get more power out of the fours, the next issue you would have to face is the transmissions that are hung on the back. You will scatter parts all over a trail with more HP under your right foot.
Now what does the four banger offer? The SE's are a thinking mans Jeep. They are small and light. They are simple, with few options to fail over time. They are easy to work on. The axles, Dana 30 and 35's, are perfectly adequate for the fours with a little upgrading. The transfer case is way stronger than it needs to be, so don't worry about that. The transmission is barely adequate, but it does work if used with a little discretion. It'll last a long, long time if you don't hammer on it.
When you go to modify your four cylinder TJ, don't start dreaming of 35" MT tires and huge lifts, body armor, meaty bumpers and huge winches. Just don't go there with the fours. Think 33" tires, with 32's being better and 31's being best. Think 1 to 2" of suspension lift and no more than 1 1/4" of body lift. Think light weight and simplicity everywhere.
More later...