Sponsored

Getting more power out of the 3.6 (even a little)!

OP
OP

kjl2020

Well-Known Member
First Name
Chris
Joined
Jul 20, 2020
Threads
11
Messages
101
Reaction score
66
Location
DeKalb, Illinois
Vehicle(s)
2020 Wrangler 2-Door
Clubs
 
Change gearing. The 3.45 stock gearing is not great. It's basically a 5 speed, best fuel mileage at 60 is 4th gear, 5th gear is good 65 to upper 70's. 6th gear isn't even usable until nearly 80 if there's even a small hill (I live at 3000 ft).

I think that if you can loaf it along at 17-1800 rpm on the flat lands with low load at 65-68 mpg in 5th, you could achieve a little better economy, but we live where it's up and down hill in any direction. Loading it at 1800 in a higher gear on and off, hurts the economy. It does better a little over 2000 rpm. I have over 4000 miles of experimentation playing with this, and these are my observations on a 2 door, 6 speed Willys with 3.45 gears and 33" Falken AT3W's.

In my opinion, 3.73 would be an okay gear for stock tires, but 4.10 with 33" tires puts it in a very good sweet spot.

I've experimented and found the 3.6 likes 2000-2100 for lower speed cruise, and 2200-2300 for freeway speeds and some hills. I'm getting better fuel mileage in 5th at 76-78 mph (commute 30 miles each way to work) than 6th. 6th is only turning 2000 rpm at 80, which won't pull hills. I'm averaging 21 ish (20.5-21.5 on the freeway using 5th, where I lose 1 to 1.5 mpg using 6th (19.5-20).

At 60 on the back roads, 4th at around 2100 rpm does better than 5th at just over 1700. 22-24 mpg at those speeds (hill dependent). 70-72 is the sweet spot for 5th on the 2 lane back road (65-70 zone).

Going to 4.10 puts the rpm in the sweet spot for 4th around 50, 5th is 60-68, 6th is 69+. It's only turning 2400 at 80.

Also, that's a decent reduction in ratio in the lower gears, which will feel a lot peppier. As a bonus, 3rd gear becomes usable in the 25-35 range for offroad gravel road running (mountain gravel roads) which is a good place to be for mountain running. 4th gear becomes the fast gravel gear. Right now, 2nd is too short and 3rd is too tall for the winding mountain gravel roads we like.

I agree with the people that say 4.56 with the 6 speed manual and 35" tires. That puts it at very similar RPM vs. speed.

We'll be swapping out the 3.45's for 4.10 this weekend. Would like to get to where we have a usable 6 spd transmission, instead of a 5 speed, which is what we have now.

As for power, Livernois, depending on which ECM you have. Looks like the 6 speed guys are getting the GPEC2A that can be jail broken. Nothing for the '22 yet, but the older ones have a tune. Even the 87 octane tune is about 11 HP at the peak, but gets rid of the mid-range drop and ends up being 30 HP in the mid-range. The 91 octane tune delivers a lot more at the peak, and more power everywhere from 2000 up.
How do you figure out which ECM you have?
Sponsored

 

OnlyOne

Banned
Banned
Banned
Joined
Feb 17, 2018
Threads
37
Messages
1,676
Reaction score
3,226
Location
Northwestern New Mexico
Vehicle(s)
2021 Sport S Diesel on 37s
Unfortunately, other that forced Induction theres not a lot to help other than a regear.
 

Old Dogger

Well-Known Member
First Name
Bill
Joined
Nov 15, 2021
Threads
11
Messages
1,706
Reaction score
1,863
Location
Cave Creek Arizona
Vehicle(s)
2013 JKR, 2018 JLR
Occupation
Retired High level Management.
Less weight = more power and better fuel economy. Remove as much extra weight as possible. Rear seat, spare tire, and anything else that you have added such as a winch and heavy steel upgraded bumpers, skids. Only fill your gas tank about half way. ADD more air pressure to your tires. Make sure that you have a clean engine air filter. Some may laugh, but this will all increase powertrain power somewhat. The OP asked for even a little more power.
 

XtremeRetard

Well-Known Member
First Name
Richard
Joined
Sep 6, 2021
Threads
19
Messages
501
Reaction score
686
Location
Rocky Mountains
Vehicle(s)
JLURXR
Build Thread
Link
Less weight = more power and better fuel economy. Remove as much extra weight as possible. Rear seat, spare tire, and anything else that you have added such as a winch and heavy steel upgraded bumpers, skids. Only fill your gas tank about half way. ADD more air pressure to your tires. Make sure that you have a clean engine air filter. Some may laugh, but this will all increase powertrain power somewhat. The OP asked for even a little more power.
Err, all of that adds ZERO power. All it does is increase the power to weight ratio of course.
 

Sponsored

zrickety

Banned
Banned
Banned
Joined
Aug 7, 2020
Threads
20
Messages
1,549
Reaction score
1,844
Location
USA
Vehicle(s)
2020 Rubicon 2DR 3.6L 6MT, VW 2.0T
Build Thread
Link
Occupation
Technician
Does anyone have real world experience with getting more power out of the 3.6? Perhaps with a CAI, better flowing exhaust, or other cheaper mod? Without going forced induction due to the cost. Just looking to squeeze even a little more out of it!
Blackhawk or similar CAI, Dynomax muffler delete, spare tire delete. That's what I did, it's pretty quick!
 

seanpublic

Member
Joined
Apr 14, 2019
Threads
1
Messages
22
Reaction score
41
Location
Plano
Vehicle(s)
2021 Wrangler JLU Sport S
Keep in mind, the 3.6L makes peak power at 6400 with the rev limiter at 6500. To get the most power, wind it out and shift before hitting the rev limiter. Best of all, this power is free compared to increasing power at lower rpms and never using what's available at the top end. It's also designed and more rigorously tested by the manufacturer for its current power levels (under a wider range of conditions). An aftermarket tune takes up all the slack that a factory engineer puts in for the chance of filling with some crap gas and running at unusual temp/pressure.

If you're already winding out the gears and feel like you need more power from the engine, then disregard this post.
 

roaniecowpony

Well-Known Member
Joined
Dec 4, 2018
Threads
151
Messages
7,575
Reaction score
10,008
Location
SoCal
Vehicle(s)
2018 JLUR, 14 GMC 1500 CC All TERRAIN
Occupation
Retired Engineer
When they had under 100 hp, people were looking for more. Now that it has 285 hp people are looking even more. "A little more" will get you quickly to "I need more", and finally "can't have too much". IMO. Just get a fast car and save your money.
 

Rubi SoHo

Well-Known Member
Joined
Aug 23, 2021
Threads
26
Messages
785
Reaction score
1,670
Location
Utah
Vehicle(s)
2021 JLUR-XR
Occupation
Physician
I’m amazed at how much quicker my 3.6 feels even without the hardtop. Look for ways to reduce weight. Doesn’t increase power per-se, but it will make your jeep feel quicker.
 
Last edited:

Sponsored

Astro Jeep

Well-Known Member
First Name
Darryl
Joined
Nov 13, 2021
Threads
25
Messages
541
Reaction score
1,564
Location
Wherever I am.
Vehicle(s)
2022 Silver Zynith JLURD
Build Thread
Link
Occupation
Retired Marine, Full-time Overlander.
Do yourself a favor. Sell it and get a diesel.
 

Oncorhynchus

Well-Known Member
First Name
Moishe
Joined
Aug 30, 2020
Threads
49
Messages
670
Reaction score
876
Location
San Jose, CA
Vehicle(s)
2018 JLU Sahara Sting Gray 3.6L
Omg guys, it’s a Jeep. Enjoy it for what it is, the original overlander. My 3.6 six speed has plenty of speed and torque, any more I’d be tipping it.
Hey OP, this is good advice. The answer lies not in an ECM module but in the mirror.
 

kah.mun.rah

Well-Known Member
First Name
Merenkahre Jr.
Joined
May 16, 2022
Threads
22
Messages
2,224
Reaction score
4,327
Location
Duat
Vehicle(s)
2021 Wrangler Unlimited Rubicon
I have the Injen Technology cold air intake and the Injen Technology dual exhaust system on my 3.6L. Not sure how much added power they give but they sure make it sound faster.

Jeep Wrangler JL Getting more power out of the 3.6 (even a little)! 1653459814476


Jeep Wrangler JL Getting more power out of the 3.6 (even a little)! 1653459841623
 
 



Top