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Is the 3.8L vs. 3.6L that important?

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101K views 41 replies 30 participants last post by  Wolfslash16  
#1 ·
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
 
#4 ·
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.
 
#9 ·
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.
 
#15 ·
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.
 
#14 ·
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.
 
#16 ·
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.
 
#17 ·
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.
 
#19 ·
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.
 
#22 ·
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.
 
#23 ·
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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#25 ·
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.
No whining now...
 
#27 ·
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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#30 ·
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.
 
#33 ·
I would test drive both and make your decision from there. No amount of asking on the internet is going help you decide


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