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3.6L Pentastar V6 24V VVT Upgraded Engine vs. Current JK Engine

DanW

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Isn't the whole design philosophy of the Pentastar to keep costs down?
No. That's only part of the complex equation. If low cost were the design philosophy, we'd still have the 3.8 or some other pushrod design, which are cheaper to produce.
 

DanW

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Does the Pentastar Upgrade have cylinder deactivation?
I don't believe it does. In all I've read about the update, I've not seen anything suggesting it.
 

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Is anyone able to superimpose the Pentastar Upgrade torque/horsepower performance curves with that of the EcoDiesel (and also the Turbo when we get it)? That would be very interesting to see.
 

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BillyHW

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So why is the newer Pentastar Upgrade engine in the JL tuned to produce *exactly* the same peak hp and torque numbers as before?

Wouldn't that have been hard to do even if you wanted to? It's got different compression ratio, cooled EGR, different oil weight...it seems like the numbers would have changed slightly just because reasons.
 

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Wouldn't that have been hard to do even if you wanted to? It's got different compression ratio, cooled EGR, different oil weight...it seems like the numbers would have changed slightly just because reasons.
It's marketing. Numbers always change. Maybe the engine does make more power but it's lost in the more complex driveline but if you told people it made more power then people would be expecting it.
 

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Torque Talk.....Does anyone know the weight of the 3.0 diesel and beefier tranny to compare with the "lightest Pentastar Ever" 326 lbs and trans? I can handle the extra initial cost of the Motori if the regeneration and injectors don't bankrupt me. What I really want is someone to convince me the diesel isn't going to implode. My previous two 12 Valve Cummins 5.9's were great. My new marine 24 valve electronically controlled 5.9 Cummins required a new computer that Cummins NW didn't have in stock.
 

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I was pretty disappointed that they didn't tweak the 3.6 up closer to 300 HP and Torque. I think it's been good in the JK but having just a little more would make it great. Maybe they really want to sell you on the 4 banger or the new diesel. The new diesel, if the real world MPG is right and upgrade cost not stupid, might be the ticket. We'll see.
 

DanW

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I was pretty disappointed that they didn't tweak the 3.6 up closer to 300 HP and Torque. I think it's been good in the JK but having just a little more would make it great. Maybe they really want to sell you on the 4 banger or the new diesel. The new diesel, if the real world MPG is right and upgrade cost not stupid, might be the ticket. We'll see.
Me, too, but with the low ratios in the manual transmission, and the 14% torque gain between 1k and 3k rpm, the 3.6 should feel significantly stronger. With 4.10 axle ratio in the Rubi, it'll pull 35s with no sweat. Still, 300hp and maybe 280 or 290 ft lbs of torque would have been a nice Christmas present.
 

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Idaho_7

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Definitely not the whole picture when quoting just max torque, as it doesn’t account for higher 90+% torque points in NA engines below 2,000 RPM, where they often cross-over.

People also conveniently forget that the turbo torque curve takes time to even come on line unless a truly exotic configuration, so they don’t reach the 1,500 RPM in the same time.

And of course if you’re working the engine constantly in a slow trail situation then the intercoolers efficacy drops affecting the power. Which won’t match the ideal results with one or two runs in a rolling road with fans blowing on it, etc.

Just talking max power numbers is a very blunt snapshot of the engines and provides a false narrative of a linear power build on NA engines which isn’t representative.

Looking at that Honda 1.5T torque curve, it doesn’t look like the power curve is anywhere near as flat as the range it implies, but a slowly building curve that peaks much later, whereas an engine like the Pentastar get a lot of torque (~95%) early on, then a flat build to peak much later. For all intents & purposes the 1.5T peak looks to be 4,600RPM or 700 RPM later than the 2.4L’s peak. And that 1.5T peak is very peaky.

Could be just this graph, but there are others similar that show a similar peak for the 1.5T, and it illustrates the issue quite clearly.

CC9BC9FC-B801-4956-BF92-C61AF73A4358.jpeg


Hhere’s another unlabelled 1.5T run (that was the hard part in finding examples) with the peak 4,400 RPM.

5965462A-D56E-45D3-AB0C-D69C5D727F3C.gif
Wonder if the Torque Curves for the JL's Pentastar V6 are out there to view? Or if they'll be available soon?
 
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The new updated "PSU" Pentastar has already been implemented in the Grand Cherokee and has these new upgrades:
  • 15% higher torque below 3k RPM
  • >6% better gas mileage
  • +5hp on Grand Cherokee
  • 2-speed variable valve lift (one speed for better fuel economy and another for preserving power)
  • Torque driven cam phasing valve timing system (cuts oil demand and reduces knock during hot starts, also works better with ESS).
  • New fuel injectors allow for better atomization
  • Internal friction reduced by using HG-R1 on the timing drive guide-faces, low-tension piston rings, new valve springs, carbon coated piston pins
  • Lightest Pentastar ever (326 lbs)
Hi Folks,

From what I have read the JL has the legacy (old 3.6) engine with miner changes to allow for stop-start in order to save the company $$. Does anyone have a source on the JL getting an upgraded engine? From what I read the PSU is only on the GC, with the PUG coming later to the RAM and GC. I was told most of the seat of the pants improvement comes from less engine drag (EPAS) and the 8 speed auto.
 

BillyHW

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Hi Folks,

From what I have read the JL has the legacy (old 3.6) engine with miner changes to allow for stop-start in order to save the company $$. Does anyone have a source on the JL getting an upgraded engine? From what I read the PSU is only on the GC, with the PUG coming later to the RAM and GC. I was told most of the seat of the pants improvement comes from less engine drag (EPAS) and the 8 speed auto.
What you've read is wrong. The JL has the newer Pentastar "2.0", the same one that has been in the GC since 2016 MY. This can be verified by the published oil capacity and weight requirements in the owner's manual. This newer version of the Pentastar has sometimes been called PSU and sometimes been called PUG just to confuse people.
 
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What you've read is wrong. The JL has the newer Pentastar "2.0", the same one that has been in the GC since 2016 MY. This can be verified by the published oil capacity and weight requirements in the owner's manual. This newer version of the Pentastar has sometimes been called PSU and sometimes been called PUG just to confuse people.
Ya, I'm confused. Is there anything from Jeep on it actually being an upgraded engine other than the start stop feature? I figure they would be all over that in their marketing, but so far... nothing.

Oil capacity may have changed due to different oil pan. They stretched the front of the JL by 3 inches. When the 3.6L pentastar was added to the 2012 JK, they didn't have enough room and it ended up sitting over the axle for better clearance, but less then ideal weight distribution. In the JL, they have the space to fit it. Oil viscosity requirements can change with the same engine, look at Fords 4.6l, Chryslers 3.8l... same engines, but one year to the other requiring different oil weight.
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