2018 JL Wrangler 3.6L Dyno Numbers

[TaiMc]

Hmmm really??? You running premium fuel? Not towing anything? That sounds so off... which one do u have?

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[Torero]

Time for some superchargers to drop for the JL...

I keep searching for the Sc. Not coming soon enough

 

[BlairF]

is that potentially due to your gearing in a Rubicon? I am not super knowledgeable about gears, but i would think the 4.10s are gonna be pretty weak at high speeds?

 

[TaiMc]

Interesting.

 

[WXman]

Actually that's not true. Modern ECUs will adapt to octane. I've done testing in the "old" 2012-2014 Pentastar engines and saw gains in both power and fuel economy on higher octane.

I'm not too worried about the Jeep being torque-less and slow. I have a Mach 1 in the garage if I feel like going fast. I appreciate the Wrangler for what it is.

 

[Jeepcity]

yes the manual makes the extremely poor torque of these engines very apparent. any driving below 2000 rpm. sucks !

 

[JHJLUR]

All I can say is with the 8spd auto in my Rubi, it’s the best engine combo ever to grace the wrangler (so far)..... I love it, fast, no... but, in comparison, yes.... it works very well for its intended use and the efficiency is way up over my JKU Willy’s 5spd auto with 3.73’s....... I’ve had 8-9 wranglers from YJ’s through the JL and lots of seat time in CJ’s as well, imho this combo easily bests even the venerable 4.0 which was a good engine for its time but also outlived its time.

 

[Jeepcity]

Street yes , offroad no, durability TBD .

 

[Biscuit]

Actually that's not true. Modern ECUs will adapt to octane. I've done testing in the "old" 2012-2014 Pentastar engines and saw gains in both power and fuel economy on higher octane.

Yes, ECUs will retard or advance timing on the fly - within limits. How did you objectively measure and quantify those alleged gains? I ask because higher octane fuel actually has less power and potential energy than 87.

 

[WXman]

yes the manual makes the extremely poor torque of these engines very apparent. any driving below 2000 rpm. sucks !

Part of that is because the new manual transmission in the JL is geared "taller" than the JK manual transmission, so on the road it's going to feel more sluggish by nature.

Yes, ECUs will retard or advance timing on the fly - within limits. How did you objectively measure and quantify those alleged gains? I ask because higher octane fuel actually has less power and potential energy than 87.

I did this with both a JKU and a Challenger, both equipped with a Pentastar engine. I ran them on 87 octane and hand calculated results for many weeks. Then I ran them on premium fuel from the same gas station and hand calculated the results for many weeks. After it was done, I averaged the numbers to do a regular gas vs. premium gas comparison and the premium showed an increase in fuel economy of about 6%.

In addition to that, both vehicles ran more smoothly on premium and felt noticeably more "peppy". This was particularly true of the Challenger with it's higher horsepower ECU calibration. It really loved higher octane fuel. The Challenger was equipped with a 0-60 MPH timer on the dash and the runs to 60 improved by 0.1 to 0.3 tenths on higher octane fuel. At its best point it did a 6.3 second sprint to 60 MPH on 93 octane.

 

[Lavey2750]

I have noticed an improvement running premium in my 6spd Rubi. I have not done calculations but gas mileage has improved. I believe this may have to due with the over 11.1 compression ratio in combination with higher summer temperatures.

As mention above the ratios are longer and in my opinion terrible. I would describe it like driving a 5spd and having an extra gear. The transmission encourages low rpm usage but this engine really has nothing to give down low. It’s begging for another 80ft lbs of torque down low.

 

[Biscuit]

I did this with both a JKU and a Challenger, both equipped with a Pentastar engine. I ran them on 87 octane and hand calculated results for many weeks. Then I ran them on premium fuel from the same gas station and hand calculated the results for many weeks. After it was done, I averaged the numbers to do a regular gas vs. premium gas comparison and the premium showed an increase in fuel economy of about 6%.

In addition to that, both vehicles ran more smoothly on premium and felt noticeably more "peppy". This was particularly true of the Challenger with it's higher horsepower ECU calibration. It really loved higher octane fuel. The Challenger was equipped with a 0-60 MPH timer on the dash and the runs to 60 improved by 0.1 to 0.3 tenths on higher octane fuel. At its best point it did a 6.3 second sprint to 60 MPH on 93 octane.

So what? I asked for an apples-to-apples objective assessment. You replied with an apples-to-oranges subjective opinion. I had a Charger with the 3.6L Pentastar that got 33 mpg on 87 octane, but again, so what?

A Challenger isn't a JK or a JL and a JK isn't a JL. The engines are tuned differently, the axles and transmissions are dissimilar, not to mention the weight and aerodynamic differences. Hand calculations are crude at best, almost as crude as your seat-of-the-pants dynamometer. Thanks for playing, though.

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