3.6 Torque Curves

BlackGenesis

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I agree completely that tuning can help the 3.6. The problem is the factory and any extended warranty is toast at that point if you have engine issues (because of course FCA will blame everything on the tune. It's a slam dunk denial for them).

I am curious if there is extra HP/TQ readily available, why doesn't FCA send it out of the factory like that. You would think Jeep would want to be able to advertise the best possible numbers for its engines. I have to assume its either some kind of weird politics, such as needing sportier products like the Chargers/Challengers have more power OR maybe the engineers concluded the engine will not be reliable enough long term if they pushed the power envelope.
No, FCA wanted to make sure 2.0 sells better...by loading garbage tune/calibration on v6 ECU.





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AnnDee4444

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No, FCA wanted to make sure 2.0 sells better...by loading garbage tune/calibration on v6 ECU.
Source?

I agree that it looks like FCA is pushing the 2.0 (probably due to CAFE numbers), but I don't think they would go as far as reducing the 3.6's performance.
 

Mfarr75

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No, FCA wanted to make sure 2.0 sells better...by loading garbage tune/calibration on v6 ECU.
You know, I absolutely believe that as a possibility. Why buy a little 4 banger turbo with 270HP/295TQ when you could have a V6 putting out the same. Oh well, maybe I will win the lottery and throw a supercharger on the V6. Damn the warranty, I'm rich!
 
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Not sure if this applies to the JL, but still interesting. From https://www.pentastars.com/engines/tech.php
Despite the four variants of the 3.6 already being sold — rear drive (290 hp), AWD (292 hp), FWD (283 hp), and Challenger (305 hp), there are just two head designs, two intake manifolds, and one set of internal components, including cam and pistons (this probably changed when they added the Ram setup, 305 hp, though the rep said the main advantage in the Ram was the space available for the exhaust), according to an SAE article by Paul Weissler. The Challenger's 13 horsepower increase is due to "a more aggressively designed intake air system" which increased airflow from 214 to 220 g/s.
 
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BlackGenesis

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Relevant link: https://www.jlwranglerforums.com/fo...-on-e85-for-v6-jl-wrangler.53580/post-1341256

If I'm understanding this correctly, apparently the tune is reduced on the JL due to its weight and needing to keep the ECU out of enrichment mode as much as possible (for CAFE).
Unlike other higher performance high compression engines that get tuned for premix fuel and alow for regular grade via pulling timing baced in sensors data - high compression 3.6 was tuned to run regular grade and all focus on economy.

Nevertheless aftermarket tuning can still achieve same or better mpg and offer good bump in torque even with regular gas. This tells us that OEM tune was very porly sought our, as now days a well tuned factory vehicle with similar displacement will have marginal power gain from tuning on premium and no gain on regular.
 

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Very interesting data analysis here, Andy. Thanks for providing this for the community!
 
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I've was wondering how all the aftermarket baseline dyno curves compare to each other, and found a neat website that lets you convert images into CSV data www.graphreader.com. So with some work, I've collected some baseline 3.6 dyno charts and plotted them out together.

Some observations:
  • automobile-catalog.com provides engine torque that has been estimated by a computer. I'm not sure how they do this, but I found that factoring 85% for drivetrain losses puts it about in the correct spot. Unfortunately the curve doesn't really match all the other data.
  • Some plots don't look accurate below certain RPMs, and should probably be ignored
  • not all dynos measure power equally
3.6 Stock Torque Curves.png


Sources:
Update: I did my best to get a realistic average of all the curves. The max torque is about 210 lb-ft, with above 190 lb-ft from 2250-5250. This is equal to roughly 19% drivetrain loss from the published 260 lb-ft at the crank. Here's what I took into consideration when making this average:
  • Ignored the computer generated data from automobile-catalog.com
  • Ignored the unrealistically steep sections at the beginning & ends of some of the pulls (ExtremeTerrain.com's & K&N)
  • Smoothed out minor bumps & dips from where certain data starts & stops
3.6 Stock Torque Curves.png
I found a couple more baselines to add: Holley & Injen. Holley's baseline was lower than my estimated average and Injen was higher, so I decided not to re-calculate the average at this time.

3.6 Stock Torque Curves.png



Updated Sources:
 

Nc138

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Not sure if this applies to the JL, but still interesting. From https://www.pentastars.com/engines/tech.php
Despite the four variants of the 3.6 already being sold — rear drive (290 hp), AWD (292 hp), FWD (283 hp), and Challenger (305 hp), there are just two head designs, two intake manifolds, and one set of internal components, including cam and pistons (this probably changed when they added the Ram setup, 305 hp, though the rep said the main advantage in the Ram was the space available for the exhaust), according to an SAE article by Paul Weissler. The Challenger's 13 horsepower increase is due to "a more aggressively designed intake air system" which increased airflow from 214 to 220 g/s.
Yes - this is very interesting. The 3.6 is an incredible engine with 90% torque from 1800 to 6350 RPM. Also runs on 87 and is very fuel efficient respectively. We did buy a Jeep, it’s not a Maserati although they are related somewhat. I don’t think this engine is going anywhere. If anything PSA will use it as well.

Here’s another interesting article, but about the transmission:
https://en.m.wikipedia.org/wiki/ZF_8HP_transmission

Having put over 100,000 miles on an 8 speed BMW X5 I noticed the similarity and then began researching the origins of this transmission.

I do think Jeep has been doing a great job continuous improving the product without sacrificing any core values.
 

BlackGenesis

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Not sure if this applies to the JL, but still interesting. From https://www.pentastars.com/engines/tech.php
Despite the four variants of the 3.6 already being sold — rear drive (290 hp), AWD (292 hp), FWD (283 hp), and Challenger (305 hp), there are just two head designs, two intake manifolds, and one set of internal components, including cam and pistons (this probably changed when they added the Ram setup, 305 hp, though the rep said the main advantage in the Ram was the space available for the exhaust), according to an SAE article by Paul Weissler. The Challenger's 13 horsepower increase is due to "a more aggressively designed intake air system" which increased airflow from 214 to 220 g/s.
However it looks like challenger has inferior lower intake manifold that suppsebly comes on wrangler . Since aftermarket intake does not contribute to power, difference in power can be just factory tune.

Challenger folk tend to go PUG lower manifold swap.
https://www.stevewhiteparts.com/oem-parts/mopar-intake-manifold-5281803aa
 

KansasJL

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KansasJL

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Will the pug lower intake manifold work in the JL engine bay?
 

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I must say, I am a happy owner of the 3.6, but man the TQ and HP of the engine kinda suck on paper, number wise, especially in the 2000-4000 range where the 8 speed auto tries to keep the truck during most driving (2000 most times on mine unless I get on it). Peak HP at 6000 rpm's is not much use to me in a Jeep.

Now, I know the curve is nice and steady, flat, etc., but it just seems a decent V6 in 2021 should be more like 300 HP and something close on TQ at the crank, and in the more usable portion of the rev range. That would be like 255 HP at the wheel more or less. Oh well.

I never can understand why, same engine with a different intake, maybe ECU programming on another FCA product like the Challenger or Ram is 305 HP. Why neuter the Wrangler like that?
Not only sucks on paper but in actual use. The Pentastar is such a gutless engine at lower rpm. Should have never been in a Wrangler but it was better than the 3.8.
 

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