still no jeep for me yet... but I'm just curious... some folks say the JK needs a bit more power.. and when I did my test drive it felt a little slow compared to the FJ I drove the day before. So I'm wondering, anyone know of any good and simple mods that can be done to improve the horsepower yet hopefully also not void the lifetime warranty?

I was looking at the Quadratec site for instance and they had some air filters, one of em saying it'll increase your hp by 14.. and I'm sure there's other things I'm missing.. anyway just wondering are any mods like that worth doing? Is it a noticeable difference if you do upgrades like that?

sorry of those are dumb questions, I don't really know much about engines or anything like that

 

Ideas to up the horsepower are like buttholes, everyone has one. There are several good threads about replacing the exhaust (cat-back) and Cold Air Intakes and even the Throttle Body spacers. One even talks about boring out the engine cylinders. As for warranty issues, the rule of thumb is that unless the "failure" can be directly linked to what you did, ie the O2 sensor failing as a result of using an oiled Cold Air Intake filter, then you would still be covered. Now finding a dealer that would agree with your assessment is another story.... Now, it is fairly well known that the computer in a Wrangler's engine will allow it to perform a little better once the break-in mileage is met. So, for a lot of folks the test drive is a bad example of the engine's power once it is past the break-in mileage.

 

This was definitely true in my case. Sure, I'd like a few more horses, but it was pretty dramatic the change over the first couple thousand miles.

 

^ x3: There was a very noticeable difference once I had a few thousand miles on my Jeep... and don't let other people's gripes get to you - you may find that it was plenty of power for your needs (I do!).

 

x4
I have plenty of power, cruise at 80 on the highway (cruise contol on the hills out west, no problem), or slow down and cruise the back roads. I do have the 4.10s so that helps

 

The 3.8 responds better to upgrades than the 4.0 did too.. Once its broken in and your used to the fly-by-wire feel you might not need too much extra.. I'm planning a muffler change as soon as I can to get the sound better.. and maybe a better flowing air filter but that would be it for a while.
Steve

 

Necros the JK is not so much slow as it is ''tight''. Like most guys will tell you, the computer seems to ''learn'' your driving style, after a few thousand miles it seems to open up and develop much more power. I broke mine in at a brisk pace, the ''use it don't abuse it'' rule worked well for me. I don't redline it but I don't hesitate to put my foot in it as needed. It passes well and maintains speed effortlessly on the open road. I have the 3.73 gears....

 

I also noticed improvement after break-in. For me, the 3.8L is adequate for the JK. Considering it's a big reason why my JK gets about 2-3MPG better economy than my TJ despite being bigger and heavier (with stronger axles and larger tires) I'm not complaining.

Just to touch on the HP claims for any bolt-on mods, they are usually measured at peak RPM, where you will never really use in a DD setting, look at the gains in the 2-3K range and see what you'll really get.

 

ok thanks for all the info. I was just curious.

I was planning to get a sahara 4 door but I'm wondering if maybe I should go with a rubicon? I don't plan to do any hardcore offroad rock climbing or anything, in fact the most I'd be using 4WD for is probably driving in the snow and maybe a beach or 2 to go fishing. But that said I may find myself having to tow my cousin's little boat around for those fishing trips, it's a 20" boat, mostly just for freshwater kinda stuff. He used to tow it with his subaru with no problems... the different gears on the rubicon give it a little more power, correct? When I was test driving, the dealer mentioned that the rubicon will ride a little "rougher" since it's more for offroading, i just drove the sahara they had, didn't try the rubi. But I'm starting to think that the price for a rubi isn't really that much more than the sahara I was looking at, and it already has some of the things I would consider changing like the beefier tires, etc. And the rubicon is still cheaper than the explorer I was looking at originally

 

Get the Rubi, I had a '04 TJ-Rubi and did not do much off roading. So when I decided to get a JK I figured I might as well just get the Sahara because I probably wont off road much. Well after $12,000 +- Of Mods I love off roading and I wish I got the Rubicon. Just my opinion, if you can afford a Sahara, you can afford a Rubi..