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Old 05-24-2019, 08:24 PM
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Question Is the 3.8L vs. 3.6L that important?

Hey everybody, still searching for a wrangler to make my own. I've seen a lot about the differences between the Pentastar and the 3.8L, and if I'm getting it paired with the 6 speed anyways, does it make a huge difference day to day? I don't have a lot of (stick shift) options around, and I'm trying to find one where the price is right and the mileage isn't excessive

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Old 05-24-2019, 08:35 PM   #2
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Never had a 3.8. 3.6 has been great. Lots of
Torque and great reliability.


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Old 05-24-2019, 08:59 PM   #3
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IME between the two engines the 3.6 excels as a DD but both engines are fine when properly geared for the off-road trails.
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Old 05-24-2019, 09:15 PM   #4
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If you're set on the 6-speed manual, then no it's not that big of a deal as long as you have the lower axle gears (3.73 or 4.10). Day to day, 3.8 or 3.6 will perform similar.

The 3.6 may have better mid-range punch and a higher powerband; but under 2,000 RPM it really lacks torque. I am disappointed with the 3.6 in my JKUR.
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Old 05-24-2019, 09:17 PM   #5
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I've made this comment before... but I am personally happy for the "bad press" around the 3.8, and specifically the 2011 bastard year.

Thanks to that, I was able to get my 2011 JKUR (with super low miles) at a great price. And I couldn't be happier.
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Old 05-24-2019, 09:27 PM   #6
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Had a 3.8, on a JK with 4.10s and manual on 35s. Tuned it a bit with a Superchips to make me feel better...

It was fine
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Old 05-24-2019, 10:09 PM   #7
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I have 176,000 on my 07 JKU 3.8 auto with a 4.10 rear end. Runs great.
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Old 05-24-2019, 10:38 PM   #8
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I have a 2 Door 3.6 with 3.73 and i love it. My sister has a 4 Door 3.8 and hates it and wishes her jeep drove like mine. Trying to convince her into a re gear. best of luck to ya!
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Old 05-25-2019, 11:10 AM   #9
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When my brother-in-law bought a new 2012 Sport late in 2011, we both test drove brand new 2 doors. One with a 3.8 and immediately jumped into a Sport with a 3.6. The difference was VERY noticeable. I think the HP difference was only 55 or so, but it was VERY noticeable when accelerating away from a stop sign or getting onto a freeway (and I'm sure, when towing anything). It would be very hard to test drive two similar jeeps back to back now, but in the brand new ones we test drove, the 55 hp made the sale on the newer jeep/engine, even thought the 2011 was several thousand $'s cheaper.
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Old 05-25-2019, 11:27 AM   #10
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3.8 = 200hp
3.6 = 280hp
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Old 05-25-2019, 12:01 PM   #11
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I've made this comment before... but I am personally happy for the "bad press" around the 3.8, and specifically the 2011 bastard year.

Thanks to that, I was able to get my 2011 JKUR (with super low miles) at a great price. And I couldn't be happier.
Life is Good: 2011 JKUR (with super low miles) at a great price. I would be happy So much potential like a future V8 conversion delivering higher power with similar mpg.
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Old 05-25-2019, 12:13 PM   #12
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I've owned two of each. The difference is profound. The 3.6 feels like a healthy six. The 3.8 feels like a healthy six with two plug wires removed.
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Old 05-25-2019, 12:19 PM   #13
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Quote:
Originally Posted by stillmurphee View Post
Hey everybody, still searching for a wrangler to make my own. I've seen a lot about the differences between the Pentastar and the 3.8L, and if I'm getting it paired with the 6 speed anyways, does it make a huge difference day to day? I don't have a lot of (stick shift) options around, and I'm trying to find one where the price is right and the mileage isn't excessive
Watch the video and decide for yourself.

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Old 05-25-2019, 07:09 PM   #14
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I would recommend checking further into the transmission differences between the 3.8L and 3.6L.

People are chiming in about their personal experiences when driving a 3.8 vs 3.6 but one of the key differences aside from the engines are that the 3.6L "automatic" has a much better Mercedes W5A580 5-speed trans vs the 3.8L's 42RLE 4-Speed Trans.

Now when it comes to the manual transmissions that you're looking at, both the 3.8L and 3.6L use the same 6-Speed NSG370 trans and there's a much less noticeable difference and some have said that the NSG370 seems better when paired with the 3.8L, than the 3.6L but that's subjective.

I have no personal experience with the manual trans on the 3.8L or 3.6L and can't say for certain one way or the other, but just wanted to point out that when folks start talking about those huge differences they noticed between the 3.6L and 3.8L, they're typically referring to the automatic transmission models.
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Old 05-25-2019, 07:11 PM   #15
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Watch the video and decide for yourself.

https://youtu.be/xdR30oIsU1E
To the point I just made, he's asking about 3.6L vs 3.8L JK's with a manual trans and that video shows the differences between them with the auto's where there's more than just an engine difference on the autos. #TransmissonsMatter.
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Old 05-25-2019, 09:55 PM   #16
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Owned 2 3.8s[07 and 10] both 2 door auto trans, the 07 was 3.08 the 10 was Rubicon 4.10 both gave me 60k trouble free miles the 07 was a dog on hills but got the job done. My current ride is a 14 JKU with 3.73 and auto it is defiantly a better power train but I would not be detoured from buying another 3.8 if finances dictated it.
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Old 05-25-2019, 11:44 PM   #17
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Let's be honest. Besides price point, there's not a reason the 3.8 is better. Unless you get a 2011, a 3.6 is going to have the better auto trans, better interior, and better brakes. 2012 and newer have the larger master cylinder. The 3.6 is easier to engine swap if wanted too. Getting a 3.6 might cost more, but there's a reason.
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Old 05-26-2019, 12:38 AM   #18
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Originally Posted by rednroll View Post
To the point I just made, he's asking about 3.6L vs 3.8L JK's with a manual trans and that video shows the differences between them with the auto's where there's more than just an engine difference on the autos. #TransmissonsMatter.
Yeah, I hadn't noticed that he was talking about the 6-speed. I imagine similar results would show if they were both manuals in the video and the two different engines. The big factor in that matchup would be how well the driver shifts. It takes that variable out of the test when they are both autos.
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Old 05-26-2019, 01:56 AM   #19
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I loved my 3.8 KJ with 5 speed NV3550 - it is somewhere the same weight and HP as JK.
Never felt under-powered but it wasn't a sport car either. MPG sucked.
I drove Pentastar JKs 2dr MT and 4dr AT.
2DR MT soft top drives like a small fast tank, my favorite.
MPG is way better compared to KJ.
Stock 2DR with pentastar can go up to 25MPG HW maybe more.
It sounds like a sewing machine- but that is how most modern engines are.
It runs hot- same as above
Has weak heads components- they sort of fixed it but i would pay attention to any previous motor repairs, or unusual noises.
Pentastar is probably better, but you will get a better deal on 3.8.
I would suggest going with the best you can find, with less mileage, lower price, better maintained. If the motor doesn't start it doesn't really matter how many HP it has.
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Old 05-26-2019, 12:19 PM   #20
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I loved my 3.8 KJ
KJ came with a 3.7 SOHC not the 3.8 OHV that was in the JK. Completely different engines.
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Old 05-26-2019, 02:24 PM   #21
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Watch the video and decide for yourself.

https://youtu.be/xdR30oIsU1E
That’s a very good video.

My first Jeep was a 2 door yj with that straight six. That was a light Jeep and it “felt” like it had plenty of torque at the lower r’s with that engine.

My second Jeep was a 2 door 07 jk rubicon with the hard top and the heavy full doors with the automatic windows. It felt sluggish by comparison. After I added the heavy steel bumpers front and rear it was even worse.

My current ride is a 2010 2 door rubicon with a soft top and half doors. It came with 33’s. After I burned them off I went straight stock with bfg mud tires 32x10. The kind that came on them stock. I even kept the original plastic bumpers. As long as I keep this Jeep light the 3.8 is ok. I like it.

All my jeeps were/are manual transmissions.

Still the 3.6 would be a real advantage with a jku especially if you wanted bigger, heavier tires, and wheels, and nicer bumpers and such.
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Old 05-26-2019, 06:52 PM   #22
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I have two JK 3.8s, standard shift. The first one I bought had a 3.23 r/p and I hate it. Easy to stall, too fast in 4L in the woods. I then bought a 2011 Rubicon with 4.10 r/p. Like night and day, the 4.10 is so much better. If you want a standard trans, forget about 3.6 vs 3.8 look for something with 3.73 or 4.10 r/p, you will like it much better.
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Old 05-26-2019, 08:26 PM   #23
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I have a 2011 3.8 manual 2 door with 3.73 gears. My ex wife had a 2p14 3.6 manual 4 door with 3.73. The difference was noticeable when both were stock. Once I added lift and heavy 33" tires and steel bumpers to the 2011, the difference was profound.

Soon after we separated, she traded her 2014 for a 2017 Tacoma auto. As far as power goes, it ate the Jeeps for lunch. I still prefer my 2011 to the Taco, though.

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Old 05-28-2019, 06:38 PM   #24
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3.8 = 200hp
3.6 = 280hp
And there it is. That is a significant difference. Manny or auto your tush can tell.
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Old 05-28-2019, 06:59 PM   #25
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When the 3.6 Pentastar came out I wasn't initially sold. At the time I would have preferred the old straight 6 4L or a 350 swap in a CJ. Then life dictated we get a wheelchair van that came with the same 3.6 Pentastar. This ended up being a primary reason to go with a 2013 or later Jeep when I got my Rubicon last month.

You can't argue with 40 percent more horsepower.
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Old 05-28-2019, 07:04 PM   #26
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3.8 is okay
3.6 is great
4 door is okay
2 door is great
Now it's up to you.
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Old 05-28-2019, 08:22 PM   #27
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3.8 is a solid motor know for high mileage and when properly geared does just fine.
3.6 is still in infancy so who really knows how well they will stand up. They have had some pretty major issues. But it is a nice power plant and it is geared properly right from the factory. However, the 5spd Auto really is more of a game changer then the motor.


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Old 05-28-2019, 08:39 PM   #28
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Originally Posted by fsp31 View Post
I've made this comment before... but I am personally happy for the "bad press" around the 3.8, and specifically the 2011 bastard year.

Thanks to that, I was able to get my 2011 JKUR (with super low miles) at a great price. And I couldn't be happier.
What do you mean about 2011 bastard year? I just picked up a very clean 2011 with only 69k miles. It's a little flat on the tq curve but I'm pretty happy with it so far.
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Old 05-28-2019, 08:51 PM   #29
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What do you mean about 2011 bastard year?
Has the new updated interior, but the old engine.
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Old 05-30-2019, 04:09 PM   #30
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I had a 2008 JK with the 3.8L. It burned through 6 quarts of oil in between oil changes (changed every 5,000 miles). We had not been checking the oil level between oil changes. The oil light came on, then the engine seized immediately thereafter. I had to buy a new engine.

Yes, it was our fault for not checking the oil levels, but that is still some pretty heavy oil burning for a modern vehicle.

If you own a 3.8L, make sure to check the oil level at all fuel stops!

Oil burning issues aside, the 3.6 is a much better engine.

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