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Thread: How to get more Power out JK 3.8L engine

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    Icon911 How to get more Power out JK 3.8L engine

    I have a 2008 Jk with the 3.8L. The Engine is very underpowered. So i was wondering is there something i can do to get the max power out of it with out breaking the back. I already have a cool air intake and that help a very little bit. Thanks for your help.

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    Registered Atl XJ's Avatar
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    The only real differences that you are going to make would be through gearing or forced induction. There are other things that will help a little bit, like tuning and exhaust, but not enough to give it the power to weight ratio that it needs.

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    ^^^ What he says.
    08 D-Yellow JKU. Rock Krawler 2.5 coil lift, RK Bomb Proof adj front track bar, RK LCA's, Bilstien 5100 shocks, Rubi sliders, Rock Hard stubby, Smitty XRC8 Pro winch w synthetic line, 17x9 Incubus 511's w 33x12.5 Pro Comp A/T's, KC long range Slimlights, Banks Ram Air CAI, Magnaflow exhaust, and some other small stuff.

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    Default so....

    I got my 09 back in March, put almost 10k on since, granted it is not a muscle car and does not perform like one, it seems to meet my performance expectations for a Jeep.

    What level of performance are people looking for?
    BT
    '09 White Rubicon Unlimited, stock.
    '97 Black TJ 4.0 5Spd, Bestop SunRider Soft-top, Bestop Safari top, BDS 3in springs, Skyjacker hydros, JKS Quicker Discos, BJOTF K&N air intake, Detroit locked rear, 32X11.5 on canyons

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    Something that can keep up with a Corolla on the passes would be nice.

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    Quote Originally Posted by Atl XJ View Post
    Something that can keep up with a Corolla on the passes would be nice.
    Buy a Civic SI if you want to keep up with a Corolla.
    BT
    '09 White Rubicon Unlimited, stock.
    '97 Black TJ 4.0 5Spd, Bestop SunRider Soft-top, Bestop Safari top, BDS 3in springs, Skyjacker hydros, JKS Quicker Discos, BJOTF K&N air intake, Detroit locked rear, 32X11.5 on canyons

  7. #7

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    Quote Originally Posted by btadlock View Post
    Buy a Civic SI if you want to keep up with a Corolla.
    In the snow?

  8. #8

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    Quote Originally Posted by JKTheBeast View Post
    I have a 2008 Jk with the 3.8L. The Engine is very underpowered. So i was wondering is there something i can do to get the max power out of it with out breaking the back. I already have a cool air intake and that help a very little bit. Thanks for your help.

    Trade it in for a 2012.
    Yours has held it's value quite well.
    By the time you put a cat back, chip it, and supercharge it, etc?

    I also have found that the free flow intake systems do not really enhance performance, unless it has a "ram air" type setup.
    Too much hot air under the hood.

    A K&N panel filter alone may allow a 4-5 HP gain, with no intake resonance.

  9. #9

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    Quote Originally Posted by Atl XJ View Post
    The only real differences that you are going to make would be through gearing or forced induction. There are other things that will help a little bit, like tuning and exhaust, but not enough to give it the power to weight ratio that it needs.
    That is why the 2012 Sport is so intriguing.
    1000 LBS. less than a Grand Cherokee?
    Amazing.

    3760 lbs with 285 HP?

    The prior Generation Z28/Trans AM had 275 HP/325 ft-lb Tq in the mid 90s....
    Curb weight of 3400+.
    0-60 5.7 seconds.
    The 2012 Wrangler has got to be in the 7 second range.
    (just a little weak on the torque)

    Imagine blowing BY the Civic Si on the way to the Republic of Boulder.
    Even with a load of Fat Tire in the back.

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    I agree wholeheartedly. Its not much to ask for it to have a decent power to weight ratio. I'm not trying to race anyone, I just want for it to be able to get out of its own way. I think that the 3.6l will do just fine. The 4.0l in my Xterra isn't a race car, but it had plenty of power in the passes and gets the same MPG. It weighs roughly the same as my Rubicon did, and it has roughly the same power as the 3.6l. Just reverse the hp and torque figures...

    Btadlock just doesn't get our point. We aren't trying to race anyone, we just don't want to be frustrated and disappointed.

  11. #11

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    Quote Originally Posted by Atl XJ View Post
    I agree wholeheartedly. Its not much to ask for it to have a decent power to weight ratio. I'm not trying to race anyone, I just want for it to be able to get out of its own way. I think that the 3.6l will do just fine. The 4.0l in my Xterra isn't a race car, but it had plenty of power in the passes and gets the same MPG. It weighs roughly the same as my Rubicon did, and it has roughly the same power as the 3.6l. Just reverse the hp and torque figures...

    Btadlock just doesn't get our point. We aren't trying to race anyone, we just don't want to be frustrated and disappointed.
    Unfortunately, driving an underpowered vehicle can be dangerous...

    A few points on the Nissan Frontier/Xterra.

    Great frame/chassis. Shortened version of the Titan, from what I recall.
    One of the best V-6's on the market.
    Both are fun to drive.

    Complaints:
    interior plastics/leather should be nicer for a 30k vehicle. Cargo area scratches too easily.
    Some of the body parts are quite flimsy.
    Fuel filler door thin as a pop can, inner wheel well plastic where it meets the fender traps salt/mud/etc. Rear seat belts on Xterra are a poor design.
    Tailgate on Frontier. Weight, fit, cables to support it.

  12. #12

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    Quote Originally Posted by Atl XJ View Post
    I agree wholeheartedly. Its not much to ask for it to have a decent power to weight ratio. I'm not trying to race anyone, I just want for it to be able to get out of its own way. I think that the 3.6l will do just fine. The 4.0l in my Xterra isn't a race car, but it had plenty of power in the passes and gets the same MPG. It weighs roughly the same as my Rubicon did, and it has roughly the same power as the 3.6l. Just reverse the hp and torque figures...

    Btadlock just doesn't get our point. We aren't trying to race anyone, we just don't want to be frustrated and disappointed.

    It appears that the 2012 Wrangler Sport weighs 600 lbs less than an Xterra.
    Good point about the reversal of the HP/Tq numbers.
    Funny about how the weight of oversized wheels and tires influences performance. Unsprung.

    For instance, the Ford Edge SEL AWD is quicker than the (un)Sport that is rolling on 22" wheels. Despite the latter having a 3.7L motor with more HP.

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    Quote Originally Posted by Atl XJ View Post
    I agree wholeheartedly. Its not much to ask for it to have a decent power to weight ratio. I'm not trying to race anyone, I just want for it to be able to get out of its own way. I think that the 3.6l will do just fine. The 4.0l in my Xterra isn't a race car, but it had plenty of power in the passes and gets the same MPG. It weighs roughly the same as my Rubicon did, and it has roughly the same power as the 3.6l. Just reverse the hp and torque figures...

    Btadlock just doesn't get our point. We aren't trying to race anyone, we just don't want to be frustrated and disappointed.
    You are right, I don't get your point, I have never purchased a jeep expecting highway performance, realizing that a compromise would have to be made for off road performance. Since I am neither frustrated or disappointed, I must have set my expectations too low.
    BT
    '09 White Rubicon Unlimited, stock.
    '97 Black TJ 4.0 5Spd, Bestop SunRider Soft-top, Bestop Safari top, BDS 3in springs, Skyjacker hydros, JKS Quicker Discos, BJOTF K&N air intake, Detroit locked rear, 32X11.5 on canyons

  14. #14
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    Quote Originally Posted by NEOJeep View Post
    Unfortunately, driving an underpowered vehicle can be dangerous...

    A few points on the Nissan Frontier/Xterra.

    Great frame/chassis. Shortened version of the Titan, from what I recall.
    One of the best V-6's on the market.
    Both are fun to drive.

    Complaints:
    interior plastics/leather should be nicer for a 30k vehicle. Cargo area scratches too easily.
    Some of the body parts are quite flimsy.
    Fuel filler door thin as a pop can, inner wheel well plastic where it meets the fender traps salt/mud/etc. Rear seat belts on Xterra are a poor design.
    Tailgate on Frontier. Weight, fit, cables to support it.
    I love my Xterra, it is a great compromise for me, giving me great drivability, with most of the offroad ability that you get with a Wrangler. I totally agree on the plastics scratching too easily, but I don't mind the interior. I like its utilitarian nature and the tons of storage that it offered. The only thing that I had to do was replace the factory stereo (mine was non RF) and add an OEM looking Clarion double DIN so I got bluetooth, sat radio, iPod hook up, etc. An added bonus is that it makes the dash look much nicer and less cheap looking. I also added a weathertec rubber mat to the cargo area to keep my lab from sliding around. I had weathertec floor liners all the way around, I highly recommend them.

    I haven't noticed any of the other issues that you mentioned and you are correct that it is on the Titan platform.

    All of that being said, I will probably be selling it in a few years to get a '12+ JK. With the new engine and interior, I think it will finally be the perfect vehicle for me. Either that, or I'll be smart and just keep it because it will be paid off by then.

  15. #15

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    Quote Originally Posted by Atl XJ View Post
    I love my Xterra, it is a great compromise for me, giving me great drivability, with most of the offroad ability that you get with a Wrangler. I totally agree on the plastics scratching too easily, but I don't mind the interior. I like its utilitarian nature and the tons of storage that it offered. The only thing that I had to do was replace the factory stereo (mine was non RF) and add an OEM looking Clarion double DIN so I got bluetooth, sat radio, iPod hook up, etc. An added bonus is that it makes the dash look much nicer and less cheap looking. I also added a weathertec rubber mat to the cargo area to keep my lab from sliding around. I had weathertec floor liners all the way around, I highly recommend them.

    I haven't noticed any of the other issues that you mentioned and you are correct that it is on the Titan platform.

    All of that being said, I will probably be selling it in a few years to get a '12+ JK. With the new engine and interior, I think it will finally be the perfect vehicle for me. Either that, or I'll be smart and just keep it because it will be paid off by then.
    Make sure to check the inside of the fenders where the inside plastic meets the upper fender's metal flange.
    It is not sealed or equipped with drainage channels/holes.
    Future problems, in my opinion.

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    Registered Atl XJ's Avatar
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    I will check that out, but I hit mine with a pressure washer quite often so it shouldn't be an issue. Btw, my Xterra and my Rubicon weigh within ~100 lbs of each other.

  17. #17

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    Quote Originally Posted by Atl XJ View Post
    I will check that out, but I hit mine with a pressure washer quite often so it shouldn't be an issue. Btw, my Xterra and my Rubicon weigh within ~100 lbs of each other.
    Be careful with the pressure washer. May push chemicals FURTHER into the nooks and crannies that they forgot to account for in Smyrna.

    Weight?

    That is why the Sport with Trac-Lok should be a deal.

    3760 lbs in the 2 door.

  18. #18

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    This is why I have a fast car, a somewhat fast car, and my very slow JK-U. A car for every mood ;-)

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