3.7 is a dog....Need more Power!

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Katmandu

Full Access Member
Joined
Nov 13, 2005
Messages
78
Reaction score
0
Location
Troy, Ohio
What can be done to get more power out of a 3.7 ? Not interested in turbocharging, supercharging, nitros or gear changing.

Just looking for some more gusto from the 3.7.
 

Dave

Administrator
KJ Supporting Member
KK Supporting Member
Joined
Feb 22, 2006
Messages
15,567
Reaction score
15
Location
on here
If you need power and you want a Jeep, you need an SRT8 Grand. The one I drove had plenty of power anyway. Even the small V-8 has power. The 3.7....not so much.

Anything you do to the 3.7 is not going to make much difference so don't waste your money trying to make it what it isn't.

Just my opinion.

Dave
 

CzarKJ

Full Access Member
Joined
Mar 3, 2013
Messages
2,605
Reaction score
3
Location
Townsend, MA
How old are your plugs? Those could cause a lack of power. Also adding a performance exaust gave me a little extra, not a ton but some.
 

QuickSilver

Full Access Member
Joined
Aug 5, 2013
Messages
54
Reaction score
1
Location
San Diego, CA
You could try a canned or custom tune using something like the DiabloSport Trinity Tuner (and yes, they do build one for the Jeep 3.7L V6). But be advised the power increase tunes usually come with a tradeoff such as decreased MPG coupled with a requirement for higher octane fuel.
 

tjkj2002

Full Access Member
Joined
Dec 17, 2006
Messages
10,612
Reaction score
39
Location
Somewhere between being sane and insane!
Re-gear to 4.10's,the only sure fire way to get a performance increase.

Tuners,intake,and exhaust will cost just as much as re-gearing and give a fraction of the gain.Re-gearing also gives you more low end punch were as tuners and all that is all high end(4000rpm's+ only).
 

Katmandu

Full Access Member
Joined
Nov 13, 2005
Messages
78
Reaction score
0
Location
Troy, Ohio
You could try a canned or custom tune using something like the DiabloSport Trinity Tuner (and yes, they do build one for the Jeep 3.7L V6).

But be advised the power increase tunes usually come with a tradeoff such as decreased MPG coupled with a requirement for higher octane fuel.
I recently traded in a 2012 Mustang with a 3.7 V6 (DOHC, direct injected, VVT...way different engine than the dinosaur in the Liberty)..... I put a canned tune (SCT SC3), CAI, cat-back exhaust and woke that thing up BIG TIME ! At least a 20-25HP increase. My Highway MPGs actually increased substantially. 32-34 MPG Highway consistently (2.73 rear gear). No BS.

I'm not expecting all that from the Liberty dinosaur 3.7 pushrod in anyway shape or form, but I would really like it to have a bit more gumption!

So just how good are these canned tunes on the Liberty's 3.7 ?
 
Last edited:

tjkj2002

Full Access Member
Joined
Dec 17, 2006
Messages
10,612
Reaction score
39
Location
Somewhere between being sane and insane!
I recently traded in a 2012 Mustang with a 3.7 V6 (DOHC, direct injected, VVT...way different engine than the dinosaur in the Liberty)..... I put a canned tune (SCT SC3), CAI, cat-back exhaust and woke that thing up BIG TIME ! At least a 20-25HP increase. My Highway MPGs actually increased substantially. 32-34 MPG Highway consistently (2.73 rear gear). No BS.

I'm not expecting all that from the Liberty dinosaur 3.7 pushrod in anyway shape or form, but I would really like it to have a bit more gumption!

So just how good are these canned tunes on the Liberty's 3.7 ?
The 3.7 is not a puch rod engine,it's a SOHC engine.

Tunes generally will not do much if anything in a gas engine that is not direct injection(why turbo diesels see so much gain) without internal engine mods.


I have a stock 3.7 in my KJ and it weighs over 6000lbs and turning 35" tires and below 3000' in elavation I practically do a burnout everytime I take off since at 6200' you loose major power.Gear ratio,gear ratio,and gear ratio is key,I run 5.13's.
 

QuickSilver

Full Access Member
Joined
Aug 5, 2013
Messages
54
Reaction score
1
Location
San Diego, CA
You could try a canned or custom tune using something like the DiabloSport Trinity Tuner (and yes, they do build one for the Jeep 3.7L V6). But be advised the power increase tunes usually come with a tradeoff such as decreased MPG coupled with a requirement for higher octane fuel.

I recently traded in a 2012 Mustang with a 3.7 V6 (DOHC, direct injected, VVT...way different engine than the dinosaur in the Liberty)..... I put a canned tune (SCT SC3), CAI, cat-back exhaust and woke that thing up BIG TIME ! At least a 20-25HP increase. My Highway MPGs actually increased substantially. 32-34 MPG Highway consistently (2.73 rear gear). No BS.

I'm not expecting all that from the Liberty dinosaur 3.7 pushrod in anyway shape or form, but I would really like it to have a bit more gumption!

So just how good are these canned tunes on the Liberty's 3.7 ?
I was mistaken in my initial post. I thought there was a tuner for the 3.7L and there is, but it's from Hypertech and only for 2004 and later KJ's. DiabloSports does sell a tuner for Jeeps, but for the 3.8 and 4.0 engines only. My apologies for the misquote.
 

tonyrivera02

New Member
Joined
Sep 23, 2014
Messages
2
Reaction score
0
Location
Sterling, VA
Well, I have put these myths to rest by spending the time and money and see for myself if in truth the 3.7L engine is capable of more power/torque/mpg.

I spent $780

JBA SS short headers
Dynomax UltraFlow
K&N Cold Air Intake
Fastman ThrottleBody
Autolite Iridium XP SparkPlugs

After upgrades, multiple tests were run for 2 weeks and these are the results...

+ 19hp
+ 11lbs/torque
+ 0.36MPG/city - 0.80MPG/Hwy

So, I will say that even though there is no great gain overall, it sure sounds better, runs much smoother and therefore no regrets on the investment.

PS. I only use Royal Purple products for the engine, transmission, transaxle and differential. Also the $780 did not include labor charges as all labor was done by me.
 

tonyrivera02

New Member
Joined
Sep 23, 2014
Messages
2
Reaction score
0
Location
Sterling, VA
I want to add that you can't compare a 305hp DuraTec V6 with Twin-independent Variable Cam Timing (Ti-VCT), true dual exhaust and a curb weight of 3401lbs (+/-) with a (*1999-It hasn't change since) 210hp SOHC PowerTech V6 and a curb weight of 4100lbs (+/-).... sport car vs. SUV... NOT even close to same category
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
Well, I have put these myths to rest by spending the time and money and see for myself if in truth the 3.7L engine is capable of more power/torque/mpg.

I spent $780

JBA SS short headers
Dynomax UltraFlow
K&N Cold Air Intake
Fastman ThrottleBody
Autolite Iridium XP SparkPlugs

After upgrades, multiple tests were run for 2 weeks and these are the results...

+ 19hp
+ 11lbs/torque
+ 0.36MPG/city - 0.80MPG/Hwy

So, I will say that even though there is no great gain overall, it sure sounds better, runs much smoother and therefore no regrets on the investment.

PS. I only use Royal Purple products for the engine, transmission, transaxle and differential. Also the $780 did not include labor charges as all labor was done by me.

Problem is most things were a waste like the K&N filter, and throw those spark plugs away and just install good copper cores , much better and the engine will run better
 

colorado76

Full Access Member
Joined
May 16, 2011
Messages
849
Reaction score
0
Location
Rocky Mountain High
Copper Core plugs are the way to go, I tried a few different platinum plugs. They all ran like crap, so I just use the stock NGK plugs. And for K&N filter, I have a ( AKA) Cold Air Intake = Hot Air. But I like it anyway its eazy to wash and reuse. I also have a Dynomax Muffler and I like the way it sounds, but I guess want little bit of horse power we gain is not worth the price we pay. But we all have our own ideas and passions for our rides.
I want to regear next, got to save for that's lots of $$$$$.
 
Last edited:

Katmandu

Full Access Member
Joined
Nov 13, 2005
Messages
78
Reaction score
0
Location
Troy, Ohio
Well, I have put these myths to rest by spending the time and money and see for myself if in truth the 3.7L engine is capable of more power/torque/mpg.

I spent $780

So, I will say that even though there is no great gain overall, it sure sounds better, runs much smoother and therefore no regrets on the investment.

Also the $780 did not include labor charges as all labor was done by me.
$780 = 150 Pizza and Beer dinners to me!
 

Latest posts

Members online

Top