I have a 4 door 2007 automatic jk. I have 17x9 wheels with 33x12.5 tires, including spare. I have heavy bumber with winch. Also have heavy rockguards. Since i installed all these my jeep is underpower specially uphill. Some
People recommend regear. Some recommend 4.88 others 5.13. I dont plan to move to 35. I think my jeep is 4.10. Need advice to the underpower issue.

 

Hemi

 

if you are like me and NEVER plan on 35's, regear to 4.88 you wont be sorry, all i used is a pro cal to recalibrate and getting constant 17.5-18 on the highway at 70 mph. that is the math not going by comp.

 

Regear makes a very decent difference to the low end. Top end power will never be fantastic with this Engine. Ended up regearing and supercharging to make the engine perform all around. There is no cheap and easy way to get the power you are likely looking for.

 

A supercharger will make all of the difference in the world. The Jeep will run almost like it has a Hemi for a fraction of the price (and better fuel economy). RIPP sells an easy to install kit that many, including myself, love. Superchips is a solid device, but don't expect miracles. It will help, but you will still shift out of OD going up most hills.

My Unlimited will say in OD going up some pretty steep hills at 70MPH with 35's, heavy bumpers, winch, dual batteries, etc. no problem. It is a night and day difference. Every time I drive it, I can't believe how much better it runs on the highway.

 

If you read the forum long enough, I believe that you'll these find recommendations for reliable increases in power (in order of least expensive to most expensive),

1. Superchips ($300) especially if you have an automatic
2. Regear ($1000-2000)
3. Supercharger (~$5k)
4. Hemi swap ($10-25k)

A lot of people intakes and exhausts are often a matter of opinion. If you're considering an intake, think about a snorkel instead. All headers suck except the ones from RIPP.

Perhaps that's a bit harsh, but I've read just about every performance thread and that's the conclusion I've come to.

 

Yep,,, what he said. I run 35's and went with 5:13's and a super chip and am pretty happy,,, but far from perfect.

 

You may want to consider a sprint booster to eliminate the delayed throtle response. You will not get any more HP but it sure feel a lot better.

 

I don't think that's harsh at all, I think you could add the expected HP gains to these, like this:

1. Superchips ($300) especially if you have an automatic - ~25HP
2. Regear ($1000-2000) - Increases Torque, not much if any HP gains
3. Supercharger (~$5k) - ~100 HP
4. Hemi swap ($10-25k) - 150 HP
5. Headers with Tune from RIPP - ~50 HP

Cheers

 

Not to rain on your parade here but a programmer adds 10HP tops and the supercharger adds about 70HP if that. As for the headers I dont think they add 50HP cause then no one would pay $5K to gain 70HP with a supercharger.

As for the OP these engines suck so the best mod is the strip weight mod. Once my spare and rear seat came out it was like I had a new engine in my Jeep. You know you feel it already when the doors are off.