tramp

had both and a 258 i think the 3.6 is weak at low rpm while the 4.0 had lots of low end torque
kinda wishing my new wrangler had the 4.0
285hp is good but you have to get the rpm up there to work
my old 258 could walk up a hill in 4wheel high at idle

karls10jk

These jeeps are no longer made for the farmer, they're made for the 99% (which this forum does not equally represent). The majority wants a highway people mover that has that "look". They've succeeded.

shabbernigdo

imo they should of taken the I6 and just redeveloped it and added new tec to make it more powerfull and efficent. alum block / newer head design / intake etc etc

WHT_JKUR

Agree.., Miss my old 4.0.... Great low end that the 3.6 is missing. But I really like the top end of the 3.6.

larry0071

I still have a 2003 Grand Cherokee 4.0L, and I think that you are romanticizing the 4.0L in your memories! My 4.0L has low miles, 96K, we are original owners and it is impeccably maintained. Under any comparison you want to make, the 4.0L is a great engine, but sucks hind tit to the 3.6L. Fuel economy, smoothness, Low end, mid range, and top end. There is nothing at all that the 4.0L does better aside from maybe live a long, long life. We don't know yet if the 3.6 will typically go 200K-300K miles like a well maintained 4.0L.

My comparison is a 2003 GC Laredo 4.0L with factory tow package and my 2014 Wrangler 3.6L Auto 3.73.

WHT_JKUR

Don't get me wrong ... Agree... 3.6 is a much better overall motor.. Just wish it had a little more low end grunt below 2k rpm off-road. Had a manual on my last 4.0 (which I sold last year) and there was a marked difference on the bottom end. my Jk is a manual with 4.56s (running 315/70/17s) and in 4hi off road sometimes I feel like it is a little lacking only when starting out. 4.88s might make up for this, but then you lose top end. In 4lo, the 3.6 is solid! Happy with 3.6 over all, just wish that the very low end had a little more oomph.

arjeeper

I've seen a couple of these threads and they kind of throw me for a loop.

I had a couple Wranglers with the 4.0l. Great engines in their day (80s/early 90s) but should have never been in vehicles by the 2000s. Neither my TJ or LJ could drive on the freeway worth a crap.

I don't care how good a Jeep is off-road if I can't get it there comfortably and competently. If I wanted an off-road only vehicle I could get a UTV type thing.

My Jeeps are daily drivers. They have to be great at many things. For that the 3.6 is so markedly better than it's astounding.

jedg

Yup... the 4.0L at its best produced 190hp and 235 ft. lbs at 3200 rpm.

The 3.6L produces 285hp and 260 ft lbs at 4800 rpm...

so both are a bit high revving. I couldn't find actual torque curves so cant say how fast each builds that torque and how long it stays up.

mr72

The 3.6 makes more torque at all rpms than the 4.0, about +15 ft-lb more at 3200 rpm which is the peak of the 4.0's torque (235 vs. 250).

The 3.6 also makes it's peak torque for a wider range of (higher) rpm which allows it to have nearly 100 more hp, since horsepower = torque*rpm/5252 so more rpm = more hp.

The 3.6 is just a way better engine in every way. A LOT more power, significantly more torque across the board, way better fuel economy and engine management.

You may be noticing the difference in weight of the Jeep. A JK is something like 600+ lb heavier than the last Wranglers with a 4.0L I6. A 600 lb lighter JK with a Pentastar 3.6 would smoke any TJ in any category. But unfortunately no car maker besides Mazda and Lotus are capable of making a newer car that is not also heavier than the predecessor, sometimes (like in the case of a Wrangler) a lot heavier. And bigger.

jedg

Some of that 600lbs is to the credit of the better capability (like wider stance and longer control arms) and likely most is for the plusher amenities...