Sponsored

Acceleration JL vs JK

Sftdyna0326$

Well-Known Member
First Name
Carl
Joined
Apr 18, 2018
Threads
20
Messages
199
Reaction score
87
Location
New york
Vehicle(s)
2016 LR4
I’m sure it’s been covered before but I am actually amazed how much faster the JL rubicon is with the 8 speed and 4.10 years compared to the JK rubicon. The 8 speed is what makes this truck! The power to pass is a rediculous improvement compared to a JK. I just spent most of this morning flying around the neighborhood with my buddy in his rubicon do head to head a comparison! Yes, I am a very early riser. Although when comparing hardtop wind noise we both agree it’s a Jeep thing but also the JK is just a tad quieter. Both jeeps are real nice but my buddy has decided to pull the trigger on a new one after driving mine!
Sponsored

 

Rhinebeck01

Well-Known Member
Joined
May 9, 2018
Threads
155
Messages
11,869
Reaction score
17,109
Location
Multiple places..
Vehicle(s)
'18 JL Rubi, '22 Prevost M H3-45,'01 Harley FatBoy
@Sftdyna0326$

Yes, JL is way faster! Also, as a tow vehicle, the JL, shines in comparison to the JK.
 

DanW

Well-Known Member
First Name
Dan
Joined
Mar 2, 2017
Threads
159
Messages
8,404
Reaction score
11,073
Location
Indiana
Vehicle(s)
21 JLUR, 18JLUR, 08JKUR, 15 Renegade, 04 WJ
Vehicle Showcase
2
It isn't just the 8 speed. The 3.6 Pentastar Upgrade (PUG) has much to do with it. I've driven them back to back, both Rubis, both 6 speed manuals with 4.10's, and both with 35's. The JL feels stronger. Here's the kicker...the JL (mine) is a 4 door, and the JK to which it was compared is a 2 door with a significant weight advantage.

I do believe the manual transmission's gear ratios are better on the JL, but while the "old" Pentastar was strong and pulled well through the RPM band, the PUG's 2 stage variable valve timing is where the advantage lies. It optimizes at lower rpm's and then changes to optimize for higher rpms, making it pull stronger all the way from off-idle to red line. On paper, it has 14% more torque at lower and mid range rpm's, giving what was already a nice flat torque curve an even flatter one.

Oh, one more thing...My JL only had about 2000 miles on it. The other had about 35k. My engine feels like it is slightly stronger than it did then.
 
OP
OP

Sftdyna0326$

Well-Known Member
First Name
Carl
Joined
Apr 18, 2018
Threads
20
Messages
199
Reaction score
87
Location
New york
Vehicle(s)
2016 LR4
@Sftdyna0326$

Yes, JL is way faster! Also, as a tow vehicle, the JL, shines in comparison to the JK.
Spent all morning playing around, checking welds, glass and seal fitment and just going over the truck as I am so anal my wife has threatened divorce on many occasions and I do believe FCA has been addressing issues as they go along! Every hardtop,door and windshield seal along with all welds are pretty much right on, it’s by no means Mercedes perfect ( not that there really on there game anymore either) but all in all very nice. My biggest complaint is I’m a technology idiot and can’t figure out the u connect features! Last night all my daughter did was plug her phone in to charge it from the back seat and all her screen apps appeared! It was a very interesting ride home to say the least as she is only 15 and all her texts were showing!
 

Rhinebeck01

Well-Known Member
Joined
May 9, 2018
Threads
155
Messages
11,869
Reaction score
17,109
Location
Multiple places..
Vehicle(s)
'18 JL Rubi, '22 Prevost M H3-45,'01 Harley FatBoy
@Sftdyna0326$

There are two USB 3.0 ports in the back. Tell your daughter to use the other USB port and not the one that she used when you saw her contacts, texts, etc. on the JL's Infotainment Center. If she uses the other port her phone will charge but you will not see the behavior you mentioned.
 

Sponsored

DanW

Well-Known Member
First Name
Dan
Joined
Mar 2, 2017
Threads
159
Messages
8,404
Reaction score
11,073
Location
Indiana
Vehicle(s)
21 JLUR, 18JLUR, 08JKUR, 15 Renegade, 04 WJ
Vehicle Showcase
2
@Sftdyna0326$

Yes, JL is way faster! Also, as a tow vehicle, the JL, shines in comparison to the JK.
That 14% improvement in torque is exactly what to thank for that...Plus the better gearing, especially in 1st.
 
OP
OP

Sftdyna0326$

Well-Known Member
First Name
Carl
Joined
Apr 18, 2018
Threads
20
Messages
199
Reaction score
87
Location
New york
Vehicle(s)
2016 LR4
@Sftdyna0326$

There are two USB 3.0 ports in the back. Tell your daughter to use the other USB port and not the one that she used when you saw her contacts, texts, etc. on the JL's Infotainment Center. If she uses the other port her phone will charge but you will not see the behavior you mentioned.
Thanks I will do that! I’m sure you can imagine how a 15 year old responded to my wife and I getting a peek at her texts! Although she absolutely loves the alpine stereo, and I must agree it really is outstanding. I’m no audiophile but my wife’s Range Rover and Land Rover has the upgraded meridian with more speakers then Should be legal and my daughter thinks the bass kicks ass in the Jeep.
 

BDJeep1

Well-Known Member
Joined
Nov 7, 2016
Threads
7
Messages
350
Reaction score
378
Location
NW Chicago Suburbs
Vehicle(s)
JL Rubicon on order
I agree about improvement. I had a 2015 JK Rubicon Hardrock. The new JL accelerates faster and it overall a big improvement. I really liked my 2015 but the new JL is great. The soft top is such a nice improvement and is noticeably quieter than the JK.
 

Rockmaninoff

Banned
Banned
Banned
Joined
Sep 1, 2016
Threads
22
Messages
375
Reaction score
182
Location
Melbourne, Australia
Website
sophistijeep.blogspot.com
Vehicle(s)
MY2014 JKU Overland (RHD) A/T, Mercedes E-class MY2017
Can someone tell me how long it takes a stock JLU to hit 37mph/60kmph?

I've seen a video of a side by side and looks like the JK is quicker off the line.

 
Last edited:

WXman

Well-Known Member
Joined
Mar 1, 2017
Threads
61
Messages
2,855
Reaction score
3,076
Location
Central Kentucky
Vehicle(s)
2018 Wrangler Unlimited
Occupation
Meteorology and Transportation
The PUG engine may make 14% more torque at one point along the torque curve, but obviously it doesn't make 14% more peak torque because the numbers are exactly the same as the outgoing engine. The main reason the JL feels a little stronger is the improved axle gearing on base models and the 8-speed auto.

On the new 6-speed manual, the 2nd thru 6th ratios are actually taller, so roadway driving and towing actually got worse with that trans. It's the 8-speed auto that really shines in these Jeeps.
 

Sponsored

DanW

Well-Known Member
First Name
Dan
Joined
Mar 2, 2017
Threads
159
Messages
8,404
Reaction score
11,073
Location
Indiana
Vehicle(s)
21 JLUR, 18JLUR, 08JKUR, 15 Renegade, 04 WJ
Vehicle Showcase
2
The PUG engine may make 14% more torque at one point along the torque curve, but obviously it doesn't make 14% more peak torque because the numbers are exactly the same as the outgoing engine. The main reason the JL feels a little stronger is the improved axle gearing on base models and the 8-speed auto.

On the new 6-speed manual, the 2nd thru 6th ratios are actually taller, so roadway driving and towing actually got worse with that trans. It's the 8-speed auto that really shines in these Jeeps.
Never said peak torque. I believe it is between 1,200 and 3500, give or take a few hundred rpm. That's right where most people use it, every day. I also mentioned the gearing, which is a significant factor.

I have towed the same boat with the 3.6 JK and JL. The JL is superior, even with 35's. As far as taller 2nd and 3rd, it isn't by much and the engine compensates. I've driven them back to back and side by side several times. Even in 2nd and 3rd gear, my JL 4 door walks away from the 2 door JK, every time. Including and especially off the line. Again, both 4.10 axle ratio, both 35's, both 6 speeds, JL 4 door, JK 2 door. It isn't just the auto tranny.

The individual Jeeps could have some variables, but the 2 door definitely has a weight advantage. Btw, the actual measured outside diameter of the 35's on both Jeeps is nearly identical.

No doubt the 8 speed is great and has significant advantage over the outgoing 5 speed. The new 6 speed shines equally over the old, in every way. I've had nothing but manuals in my Jeeps and drive friend's late model JK's, all the time. The 6 speed is as big a leap, easily, over the outgoing 6 speed as it is with the autos, especially in refinement and NVH. Drive them back to back and you'll see. No comparo. Tow with them, and you'll still see it.

The engine is stronger, too. No way around it. Wait util you get some miles on it. Mine keeps loosening up and revving more freely as the miles tick upward, too. I'm not sure how this engine will do, but every other engine in my garage kept getting better until around 15k to 20k miles. Even the old 3.8 in my JK.
 
Last edited:
OP
OP

Sftdyna0326$

Well-Known Member
First Name
Carl
Joined
Apr 18, 2018
Threads
20
Messages
199
Reaction score
87
Location
New york
Vehicle(s)
2016 LR4
Never said peak torque. I believe it is between 1,200 and 3500, give or take a few hundred rpm. That's right where most people use it, every day. I also mentioned the gearing, which is a significant factor.

I have towed the same boat with the 3.6 JK and JL. The JL is superior, even with 35's. As far as taller 2nd and 3rd, it isn't by much and the engine compensates. I've driven them back to back and side by side several times. Even in 2nd and 3rd gear, my JL 4 door walks away from the 2 door JK, every time. Including and especially off the line. Again, both 4.10 axle ratio, both 35's, both 6 speeds, JL 4 door, JK 2 door. It isn't just the auto tranny.

The individual Jeeps could have some variables, but the 2 door definitely has a weight advantage. Btw, the actual measured outside diameter of the 35's on both Jeeps is nearly identical.

No doubt the 8 speed is great and has significant advantage over the outgoing 5 speed. The new 6 speed shines equally over the old, in every way. I've had nothing but manuals in my Jeeps and drive friend's late model JK's, all the time. The 6 speed is as big a leap, easily, over the outgoing 6 speed as it is with the autos, especially in refinement and NVH. Drive them back to back and you'll see. No comparo. Tow with them, and you'll still see it.

The engine is stronger, too. No way around it. Wait util you get some miles on it. Mine keeps loosening up and revving more freely as the miles tick upward, too. I'm not sure how this engine will do, but every other engine in my garage kept getting better until around 15k to 20k miles. Even the old 3.8 in my JK.
^^^^^^^ + 1000
 
OP
OP

Sftdyna0326$

Well-Known Member
First Name
Carl
Joined
Apr 18, 2018
Threads
20
Messages
199
Reaction score
87
Location
New york
Vehicle(s)
2016 LR4
Can someone tell me how long it takes a stock JLU to hit 37mph/60kmph?

I've seen a video of a side by side and looks like the JK is quicker off the line.

I can not speak to that video but can tell you that to 80 mph I was 7 car lengths ahead and it seemed from a dig is where i needed to keep the traction control on as I was actually spinning the rear tire! My guess is I was a full truck length ahead by 35.
 
 



Top