First Look at the 3.6L Pentastar 2012 Jeep Wrangler

[Quinn1.8t]

or, a Chyco one comparing the 4.0 to the 3.8

Uhh, I think you are reading these graphs incorrectly. Those torque curves shown for the 3.8 and 4.0 are nearly exactly the same.

[Bengti]

I love how a certain someone when quiet after everyone pointed out how he/she was reading the dyno wrong and arguing his/her point.

IMO this should be the best engine in a wrangler yet. The 4.0 I6 was great for it's time and was basically bulletproof. The 3.8 V6 was ok but geared totally wrong and had/have major problems with oil consumption in the early years, not to mention the auto tranny sucks (overheats easily). As long as there isn't a problem with reliability and it preforms as advertised, I'm sold.

[Knock Sensor]

Nice, the new motor at least makes it competitive to what Toyota and Nissan have been using for the last 5+ years.

The linked article says the engine is teamed with a 5 speed auto...i hope a manual is going to be available?!

x2

Hopefully the 6 speed stays.

[koko12]

The wrangler is finally getting a competitive engine. Now lets pray they give us one of the diesels offered in the Grand Cherokee over seas. Personally I feel the base 3.0 turbo diesel V6 with 190 hp and 330 lb/ft of torque would be a home run, a match made in heaven for a vehicle like the wrangler.

[Sledge]

Seriously, if this cracks 20mpg highway.....

...you won't buy one like every other Wrangler you wanted?

[MCTB]

I love how a certain someone when quiet after everyone pointed out how he/she was reading the dyno wrong and arguing his/her point.

Sorry, I forgot about it. So, if the dyno plots show that the 3.8 is actually better than the 4.0, why was it universally trashed? Why is this being seen as a savior then?

[Air and water do mix]

...you won't buy one like every other Wrangler you wanted?

Hey, he bought one. He must've had it for weeks, maybe months!

[SSLByron]

Sorry, I forgot about it. So, if the dyno plots show that the 3.8 is actually better than the 4.0, why was it universally trashed? Why is this being seen as a savior then?

The 3.8 was trashed because it wasn't a 4.0. The 3.6 is being praised because it's not the engine that replaced the 4.0.

Also, because it's more powerful, more refined, more efficient, and more competitive. All of those were also true of the 3.8, but it was still "just a minivan engine."

[TurboMinivan]

So, if the dyno plots show that the 3.8 is actually better than the 4.0, why was it universally trashed?

I think one key reason is vehicle weight. Most people drive a 3.8L Wrangler 4dr and complain how it isn't as peppy as a 4.0L TJ. Well no sh!t, Sherlock--the 4dr weighs almost one thousand pounds more than a SWB TJ! Try strapping a 1000-lb chunk of lead to your back and see if you don't move a bit slower.

Why is [the PentaStar] being seen as a savior then?

Because you are apparently the only person on the planet who hasn't recognized that, when compared to the 3.8L V6 and/or the 4.0L I6, the PentaStar offers equal torque from idle to 1600 RPM, better torque from there all the way to redline, gobs more horsepower and better fuel economy to boot. It's a win-win-win. Seriously, what's not to love?

[TurboMinivan]

Also, because it's more powerful, more refined, more efficient, and more competitive. All of those were also true of the 3.8, but it was still "just a minivan engine."

That's another thing--the fact that a 3.8L 4dr gets equal fuel economy as a SWB 4.0L TJ despite the four-door's added bulk speaks well of the efficiency of the 3.8L engine.

[SSLByron]

That's another thing--the fact that a 3.8L 4dr gets equal fuel economy as a SWB 4.0L TJ despite the four-door's added bulk speaks well of the efficiency of the 3.8L engine.

My dad DDed his 3.8 up 'til he retired and actually managed a lot of tanks north of 20 mpg with a good chunk of highway driving. Far cry from the 16-17 combined I normally get our of our old 2.5.

[FlashRedGLS1.8T]

About time.

[alfafan]

Apparently you need to learn the difference between a dyno plot measured at the crankshaft and a dyno plot measured at the rear wheels. When you do that, you'll get an accurate comparison... and you'll see this:



As you'll see, the Pentastar makes about 180 lb ft at 1000 RPM and hits an even 200 lb ft by 1200 RPM. You'll also notice that the Pentastar makes 240 lb ft at 2000 RPM, which is more than the 4.0L could put out at any RPM.

So, yeah, it'll do just fine and it makes a fine Jeep engine.

Ot, what caught my eye is that one of the final assembly locations is Saltillo Mexico where my mom's family came from about 130 years ago.

Bot, low gas mileage will always keep me away from a new Jeep,. If I'm gonna shell out good money for a new one I'm gonna put a fair amount of mileage on it. If I'm gonna do the weekend warrior thing then I would just get a used one and not worry about it. Again, wake me when the diesel gets here.

[Bengti]

Sorry, I forgot about it. So, if the dyno plots show that the 3.8 is actually better than the 4.0, why was it universally trashed? Why is this being seen as a savior then?

One reason, I would say, is some of it has to do to the reliability issues with the 3.8 vs the 4.0. Granted the 4.0 was in production for a long time and had all the wrinkles ironed out.

The other reason, I believe, is gearing and weight. The JK (3.8 V6) is heavier, especially the Unlimited, than the TJ was. The JK came in about the same gears as TJs (depending on models) but JK typically has 32" tires vs TJs 31" or smaller, which affect gear ratio to the bad for the JK.

Another reason for the hype about the new engine is actually not the engine but the transmission. It's a new 5-speed auto out of the Grand Cherokee vs the old 4-speed auto. The 4spd was absolutely terrible in anything lower than 4.10 gears (downshift galore) and overheated easily. I expect the new tranny to be much better overall in driving feel.

I guess the short answer is the 4.0 worked well with what the TJ had. The JK grew up but the 3.8 didn't grow up fast enough. The 3.6 pentastar appears to be an engine for the next gen Wrangler but they're putting it in the JK. To me it's the best of both worlds.

[Bengti]

My dad DDed his 3.8 up 'til he retired and actually managed a lot of tanks north of 20 mpg with a good chunk of highway driving. Far cry from the 16-17 combined I normally get our of our old 2.5.

There's your difference in bold. With the right gearing, tires, and driving you could get 20 mpg with any 2.5, 4.0, 3.8, or I'm sure 3.6.

[SSLByron]

There's your difference in bold. With the right gearing, tires, and driving you could get 20 mpg with any 2.5, 4.0, 3.8, or I'm sure 3.6.

His commute was the same distance and same split of highway/surface as mine, just on different roads. His actually had more elevation changes than mine. Driving a 2.5 "right" for fuel economy is a miserable experience. Pretty sure I can feel myself slowly dying as I accelerate up to highway speed.

[Bengti]

Driving a 2.5 "right" for fuel economy is a miserable experience. Pretty sure I can feel myself slowly dying as I accelerate up to highway speed.

A 3.8 Unlimited auto is about the same way. My theory is you're going to get crappy or crappier milage out of a jeep so why not mod the hell out of it and forget it. If you are worried about milage then you need a different or secondary vehicle.

[Spinnaker]

Seriously, if this cracks 20mpg highway.....

you'll make 27 threads about how you will/will not/will buy it?

[MCTB]

A 3.8 Unlimited auto is about the same way. My theory is you're going to get crappy or crappier milage out of a jeep so why not mod the hell out of it and forget it. If you are worried about milage then you need a different or secondary vehicle.

Not true. Im built for hell and get a constant 18 city. On highway, I can pull 22+. Difference? Diesel.