‘11 JK Sport - Painfully sluggish!

Predfan75

New member
Ya, the super charger bit was a joke (for the love of GOD do not do that). You likely have 3.21 gears (which means you didn't have much torque in the first place). I would explore getting regearing done. For a pavement princess, you likely can go with 4.56 or 4.88 gears (more torque on the low end and higher RPMs at the high end). I went from 3.21's to 4.88's on a 3.8l and it was night and day.

If there is a chance you may start wheeling it, you might want to look into the more expensive option of replacing the front Dana 30 axle and housing with a Dana 44. If you wheel the D30, you will likely break it over time and it is expensive to regear twice. :)

I would check with Essentially Offroad in Murfreesboro (I know, the is hell and gone for you, but they are a good shop) for pricing.

I am a huge Preds fan, still play hockey and went to every home game in the 2017 cup run, love the handle man!

Man thank you so much for this detailed information! This really gets me on the right path for a resolution.

As for the Preds... we have another 2-3 years in my opinion before this window closes so we’ve got to get the PP figured out and make another run!


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Predfan75

New member
New gearing will make a huge noticeable difference, intake, exhaust & tune in comparison, not so much. Google "Jeep JK 3.8 Gear Chart" be sure to use the one for the automatic and keep yourself in the middle of the green area for a on street daily driver. Be sure you measure your tire size manually for the calculation. The 3.8l engine makes decent power, its the 42RLE automatic trans that kills the whole driving experience. I would skip the bolt-ons and go straight for gears.

Will do that right now! Thank you!


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Abntroop

Member
Our last Jeep was a 2011 sport as well. Was running bfg At KO tires in a 33 (they tend to run small so was probably a high 31 low 32) with 3.21 gears on a superchips tune, volant cold air intake, and afe exhaust. Did ok until one long fast 12 hr. slog from Idaho back to Portland towing our little bantam trailer that fully loaded is 700ish lbs. By the end it was gutless power wise (not that it had much before but was at least driveable) but I’m talking pedal to the floor to do maybe 5mph up a hill to the in-laws cabin at the end. Was quite a bit better the next day, but a long bit short of how it was before. We traded it in a couple months later. It idled fine, nothing wierd. Just permanent power loss. Never figured it out.


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Last edited:

BaddestCross

Active Member
You said you used the programmer for a "tune" but did you use it to program the new tire size? If not, that will throw off the shift points and speedometer.

I don't disagree with the need for a regear, but start with the easy stuff. Don't invest in a gear job until you know what tire size you're going to end up with when you're "done" upgrading. [emoji41]



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 

Clutch

Caught the Bug
Torin - It is a Sport trim level. It's actually my wife's JK that I bought her after she kicked cancer's ass! So, it is definitely a pavement ride. I assumed the bigger wheels and tires was part of the issues and had I known the HP difference between the 3.8 and 3.6, I would have shopped for a 2012 or newer. I'm stuck now because she is in love with it...lol I would welcome your recommendations on the regear. I am a grease monkey on the side but don't think I want to get into that work.

Congrats to you and your wife! Way to stay strong in the fight!


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Predfan75

New member
Our last Jeep was a 2011 sport as well. Was running bfg At KO tires in a 33 (they tend to run small so was probably a high 31 low 32) with 3.21 gears on a superchips tune, volant cold air intake, and afe exhaust. Did ok until one long fast 12 hr. slog from Idaho back to Portland towing our little bantam trailer that fully loaded is 700ish lbs. By the end it was gutless power wise (not that it had much before but was at least driveable) but I’m talking pedal to the floor to do maybe 5mph up a hill to the in-laws cabin at the end. Was quite a bit better the next day, but a long bit short of how it was before. We traded it in a couple months later. It idled fine, nothing wierd. Just permanent power loss. Never figured it out.


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Man that’s crazy! Luckily ours isn’t that bad, it’s just the fact it feels like I’m having to really push it to get down the road. I can run 70 mph on the interstate but I have to keep the pedal hammered down for sure. Thank you for the feedback!


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Predfan75

New member
Congrats to you and your wife! Way to stay strong in the fight!


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Thank you so much! She is a fighter and very lucky to have such a great outcome. We don’t take it for granite for sure as there are tons of folks who don’t win the battle! She’s always wanted a Jeep but “it was never the right time”. So, I say screw that and took some savings I had and found the perfect one for her. She is truly in love with it so I’m determined to get the driving experience better for her! Thanks again!!


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Predfan75

New member
You said you used the programmer for a "tune" but did you use it to program the new tire size? If not, that will throw off the shift points and speedometer.

I don't disagree with the need for a regear, but start with the easy stuff. Don't invest in a gear job until you know what tire size you're going to end up with when you're "done" upgrading. [emoji41]



--
Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407

Yes I mainly got the programmer to adjust the tire size and speedometer but went ahead and loaded one of the preloaded tunes as well. It did seem to help at first but it certainly needs some additional love to improve the performance. Thank you!


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Abntroop

Member
Man that’s crazy! Luckily ours isn’t that bad, it’s just the fact it feels like I’m having to really push it to get down the road. I can run 70 mph on the interstate but I have to keep the pedal hammered down for sure. Thank you for the feedback!


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Yeah, that’s how ours felt after the above mentioned stuff. Just felt like I was having to flog the shit out of it to do regular freeway driving. I wish I knew what the issue was as it was not like that before that trip.


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Abntroop

Member
Thank you so much! She is a fighter and very lucky to have such a great outcome. We don’t take it for granite for sure as there are tons of folks who don’t win the battle! She’s always wanted a Jeep but “it was never the right time”. So, I say screw that and took some savings I had and found the perfect one for her. She is truly in love with it so I’m determined to get the driving experience better for her! Thanks again!!


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That’s awesome! And so are you![emoji1303]


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BaddestCross

Active Member
Yes I mainly got the programmer to adjust the tire size and speedometer but went ahead and loaded one of the preloaded tunes as well. It did seem to help at first but it certainly needs some additional love to improve the performance. Thank you!


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You measured actual size, right? From the ground to center of the hub x2?



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 

Predfan75

New member
Just an update on this thread.

The gegear was completed on Friday so we are in the break-in period but I could see an immediate difference in the performance. I ended up going with the 4.56 setup and so far it appears to be the right choice for the application.

Also worth mentioning... I have another thread going on a bad right pull under braking and found out I had a compromised left brake hose that was actually causing some resistance during driving and the crazy pull under braking. I replaced the hose yesterday and now between that repair and the regear, I feel the Jeep is the way it should have been from the factory!! Thank you to everyone who took time to offer suggestions and share their knowledge!!


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