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BrianBM

Jeep I-6 vs. Pentastar

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Chrysler is about to introduce a Pentastar engine with fuel injection.  I don't know whether they will do so through the intake, or directly into the cylinder, or both. That seems a long-overdue development to me, but that aside, how do those here who are using Pentastar engines like them?  Have they been reliable? 

 

A lot of guys here yearn for the old Jeep I-6.  It is said to have been supremely reliable.  When was it dropped and, if you know, why?  Just curious. 

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Brian, you're missing some detail regarding the new pentastar. They've all been fuel injected since their intro in the mid 90's in fwd chrysler products. The I6 was dropped around 2006 when the wrangler went from TJ to JK design. Most likely due to packaging. Similar deal in the grand cherokee around the same years. 

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the last american car with a carburetor was in 1990.  the 4.0 I6 is a great motor although sort of hard to compare to a pentastar.  The pentastar make 110 more hp and is newer and more reliable given that the newest 4.0 is 14 years old.  For a used car the 4.0 is a great choice.  reliable, strong and torquey.  Thirsty though.

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Boatdrinks, we have to sign you up as a more frequent visitor to this Forum.  I have lots of questions, you have answers.

 

 

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On 12/12/2017 at 10:12 AM, BrianBM said:

Boatdrinks, we have to sign you up as a more frequent visitor to this Forum.  I have lots of questions, you have answers.

haha I'll do my best

On 12/12/2017 at 10:12 AM, BrianBM said:

 

 

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We have one of both, our old '98 Grand Cherokee which is now nearly 20 years old and has 176,000 on it and my son's '17 Wrangler, which is still new (3.6 liter Pentastar and 6 speed manual). The 4.0 has more grunt off the line like  a diesel. The Pentastar is much stronger in the mid range and upper rpm range and much quieter. However, the 4.0 is much easier to work on. In all this time I've done a few tune ups, replaced the radiator and water pump, alt and A/C compressor. That's it no engine work per se. The Jeep 4.0 is really a slightly modernized AMC design (descended from the AMC 4.2 liter inline 6) and was built in Kenosha Wisconsin for approximately 40 years (all the AMC variants and the later Chrysler variants). 

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I've got the pentastar in my Ram. So far at nearly 70k miles I've had no problems. For my needs I don't feel underpowered at all and it has more than decent mpg. I also save a little on insurance and I don't have to use the mid-grade fuel recommended for the Hemi. I believe with my gear package I can tow something like 7,500 lbs, which I can't imagine ever needing to exceed.

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I expressed myself badly, I think.  I believe the new engine is going to a dual-port arrangement with fuel injection both directly into the cylinder and into an intake port.  

 

Would that be new for Pentastar?

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Go check out:

www.allpar.com

this is perhaps the best site out there with tech information on Chrysler/Jeep vehicles. 

I do not believe the Pentastar has direct port injection at this point, it may be coming in the future though. I think the new engine in the Toyota Tacoma does and it would be interesting to see what the experiences of owners of it has been. 

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Posted (edited)

There are a bunch of engines out there with direct injection.  I honestly don't know if the pentastar is or not yet but I would imagine it's coming. 

I'm into mopars and jeeps but I build the older stuff. 

Edited by jamesdart

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The old inline 4.0 is a Truck engine, noisy, vibrating like most truck engines.  producing its torque at low RPM, Built like a tank they last almost forever, I know of a Cherokee XJ with 340K on the odometer, no engine trouble ever.

The pentstar is a minivan engine, much more modern & smooth than the 4.0.

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