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Recently bought a 2011 wrangler sahara 2 door manual trans. stock 18inch wheels and tires. I am disapointed in the performance ,the engine seems to run out of power around 3500 rpm, this is most noticeable on acceleration not much there after 3500 rpm. Have 2 other jeeps one 4.0 runs great to around 4800/5000 rpm,one 4 cyl will pull good to the rev limiter(not a lot of power anywhere). Is this typical for the 3.8 engine. thanks
 

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Well the 3.8 isn't known for its power from the get go. The other jeeps were 1k lighter. However not knowing the mileage and condition of your jeep I would recommend a tune up and fluid change. May add a little pep and mpgs. Also depends on your gearing as well. You may have the 3.21s which didn't help acceleration. Good luck.
 

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Give us more info such as gears and mileage.

Peak torque is 4k and peak hp is 5k. Most performance complaints come from 4door automatics, I never felt the need for more power on stock wheels with 3.73.
 

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Recently bought a 2011 wrangler sahara 2 door manual trans. stock 18inch wheels and tires. I am disapointed in the performance ,the engine seems to run out of power around 3500 rpm, this is most noticeable on acceleration not much there after 3500 rpm. Have 2 other jeeps one 4.0 runs great to around 4800/5000 rpm,one 4 cyl will pull good to the rev limiter(not a lot of power anywhere). Is this typical for the 3.8 engine. thanks
If you have 3.21's that's the problem. Having the manual trans. is a plus when you have a 3.8. If you have 3.73's there shouldn't be much of an issue unless it's some other mechanical problem, ie. tune up, etc. I have a 2 dr. 3.8 with a manual trans. and 4.10's and I have no complaints, primarily due to the gearing. If you had a 4 dr. JK with a 3.8, auto trans and 3.21's, you would have a perfect storm for lack of performance.
 

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Thanks for the quick replys.I will check into the gearing, it has 65000 aprox miles.Is the ratio on a tag or stamped on the axel tubes or where should I look? Thanks
 

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Thanks for the quick replys.I will check into the gearing, it has 65000 aprox miles.Is the ratio on a tag or stamped on the axel tubes or where should I look? Thanks
On a JK there are no tags or markings. If you have a stock set up, meaning if you don't think anyone changed the gears which most likely wasn't done, go to this site and review your build sheet. It will indicate what gears you have from the factory: https://jeep.custhelp.com/app/jeep/eqlisting_detail/session/L3RpbWUvMTM5MzY0MzI4OC9zaWQvWGxOMmc2T2w=
 

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I have a 2008 2DR JK with the 3.8L. I use a Superchips performance tuner on 91 octane tune with stock throttle response. It improves the performance and low end torque a little bit. I also have 4.10 gears (rubicon edition) so I'm sure that helps too. I rarely if ever go above 4k rpm and usually always stay below 3.5k rpm. The 3.8L just doesn't have much above 3.5k rpm.
 

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Discussion Starter #8
Thanks for info,will check out site.Green Rubi's comments on how his jeep runs sounds a lot like the way mine runs. Why would Chrysler build a modern engine that runs no better than this?
 

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Discussion Starter #11
checked the site showing showing how jeep was equiped by vin number.It shows it has Dana 44 limited slip,3.73 gears
 

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I have basically the same in a 2010. I do have 3.73's with stock size 17" wheels. Same overall size as stock 18's. I've had the older 4.0's in the past and wouldn't go back. The 3.8 has more power than the 4.0, but is in a vehicle almost 1,000 lbs heavier. The newer 3.6 does a better job of compensating for the extra weight, but I have no power issues with mine staying with 32-33" tires. I feel the power is about the same as the 3.6 when using 35" tires all else being equal.

Both the 3.8 and 3.6 get their torque at much higher rpm's than the 4.0. This is a disadvantage with both, but is less noticeable with automatic transmissions and can be compensated for once you get used to it with a manual.

Why do you need 4000-5000 rpm? I rarely get over 2500 rpm and 3000 is about as much as I've ever needed.
 

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checked the site showing showing how jeep was equiped by vin number.It shows it has Dana 44 limited slip,3.73 gears
You have a good set-up. Other than having a 2010 2dr. manual Rubicon with 4.10's, you have the next best stock set-up having a 2dr. manual as far as getting as much performance out of a 3.8.
 

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Discussion Starter #14
Thanks for the input.I do most of my offroading in soft sand on the NC coast,most any 4x4 can dig its way along in 4low but speed works to help things.So the need for higher rpms, I normaly run in 4high,the jeep runs out of power around 3000/3500 in 1st gear not fast enough to shift to 2nd this is why I would like a little more useable rpms.
 

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Thanks for the input.I do most of my offroading in soft sand on the NC coast,most any 4x4 can dig its way along in 4low but speed works to help things.So the need for higher rpms, I normaly run in 4high,the jeep runs out of power around 3000/3500 in 1st gear not fast enough to shift to 2nd this is why I would like a little more useable rpms.
You really should be using 4L and airing down your tires, especially since you're running stock tires. On sand, speed doesn't work as well. Slow and steady works best. You can only get so much out of any JK engine, whether it's a 3.8 or 3.6. Do a search and check how other Jk owners run in sand. There might be some helpful tips that will solve your problem. Good luck.
 

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I have basically the same in a 2010. I do have 3.73's with stock size 17" wheels. Same overall size as stock 18's. I've had the older 4.0's in the past and wouldn't go back. The 3.8 has more power than the 4.0, but is in a vehicle almost 1,000 lbs heavier. The newer 3.6 does a better job of compensating for the extra weight, but I have no power issues with mine staying with 32-33" tires. I feel the power is about the same as the 3.6 when using 35" tires all else being equal. Both the 3.8 and 3.6 get their torque at much higher rpm's than the 4.0. This is a disadvantage with both, but is less noticeable with automatic transmissions and can be compensated for once you get used to it with a manual. Why do you need 4000-5000 rpm? I rarely get over 2500 rpm and 3000 is about as much as I've ever needed.
I usually at or before 3k. I will go 3.5-4k if I am using a short off ramp to get in to freeway speed traffic quickly but that is not everyday.
 

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I have a 3.8 with 35's on my Jeep and have tons of power, no complaints on the engine. I do have a Rubi so I have 4.10 gears with a manual transmission so that probably makes a huge difference. The 3.8 loves to run at about 2300 RPM when cruising. I'm confused why you are at 3,500 + RPM, that's way to high, you should be shifting at 3000 RPM
 

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Discussion Starter #19
I think we have moved away from the original question (,power output of the 3.8)and have moved to my driving.Thanks for all the info and opinions. In driving it seems the 3.8 power falls off above 3500 rpm, don't understand this in a modern engine with a max torque output at 4000 rpm,it should pull strong to the max horse power output around 5000. I think the off road problems are traction control caused and the other performance issues from the computer controled throtle .Will continue to research these ideas.
 

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I have a 3.8 with 35's on my Jeep and have tons of power, no complaints on the engine. I do have a Rubi so I have 4.10 gears with a manual transmission so that probably makes a huge difference. The 3.8 loves to run at about 2300 RPM when cruising. I'm confused why you are at 3,500 + RPM, that's way to high, you should be shifting at 3000 RPM
I also have a manual transmission which I'm told makes a noticeable difference as compared with the 3.8L and the automatic.
 
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