Rebuild Options For 50-75 More Horsepower?

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.

Michael Wolfe

Member
Joined
Feb 14, 2021
Messages
55
Reaction score
18
Location
Erie, PA
Get a CRD.
But seriously, your problem is the altitude, right, so is there a turbo setup that would just compensate for the altitude? Then a waste gate to bleed off the boost when you're not flying high? Not sure if anyone makes a waste gate that will relieve boost above 14.7 psia.
 

Buck Steele

Can't Get Avatar File Size to 2K
Joined
May 10, 2021
Messages
10
Reaction score
3
Location
Cedar City, Utah
If there was a clean, reliable, professional, complete Turbo solution I'd love to hear about it! Altitude is one of three problems. 1) It was only 210 HP to begin with, 2) 210K miles, 3) Altitude here. So, I'd probably want to run it at about 40 inches (about 20 PSI Absolute) if that was safe, etc.

Turbo diesel - how about a turbo gas solution!
 

lfhoward

Wheel. Repair. Repeat.
KJ Supporting Member
Joined
Dec 9, 2012
Messages
2,450
Reaction score
2,711
Location
Philadelphia, PA
If there was a clean, reliable, professional, complete Turbo solution I'd love to hear about it! Altitude is one of three problems. 1) It was only 210 HP to begin with, 2) 210K miles, 3) Altitude here. So, I'd probably want to run it at about 40 inches (about 20 PSI Absolute) if that was safe, etc.

Turbo diesel - how about a turbo gas solution!

I heard about a turbocharger or a supercharger that was developed for the 3.7 at one point. I believe the company was Kenne Bell. However, as the story goes, the 3.7 couldn’t handle the extra boost and the product was quickly pulled from the market. It caused catastrophic engine failures unless pistons were upgraded at the same time.

Read more here:
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=21386

and here:
https://www.jeepkj.com/threads/turbo-charging-a-3-7l-05-liberty.34938/

and here:
https://www.nitroforumz.com/threads/turbo-3-7l-low-boost-been-done.31524/
 
Last edited:

Buck Steele

Can't Get Avatar File Size to 2K
Joined
May 10, 2021
Messages
10
Reaction score
3
Location
Cedar City, Utah
Thanks. No matter how I come at the problem of the low-power 3.7, the answer is always the same: You can't get there from here!
 

lfhoward

Wheel. Repair. Repeat.
KJ Supporting Member
Joined
Dec 9, 2012
Messages
2,450
Reaction score
2,711
Location
Philadelphia, PA
Sorry to be discouraging with the links above. :(

A regear to 4.10 is a $1500-3000 investment depending on prices in your area (and if you’re adding lockers/limited slip at the same time). It’s much more affordable than a custom engine swap, and is more doable than adding HP to the 3.7. You’ll run at a higher rpm but have more torque at the wheels. It’ll be easier on your engine and transmission when you tow, as well as allowing you to accelerate more quickly and be able to hold speed going uphill without downshifting. Your miles per gallon at 65+ mph may not be as good because of running at higher rpms, but it would address some of the other issues you mention. And if you later lift it and add larger tires, you’ll be back in the stock rpm range.
 

Michael Wolfe

Member
Joined
Feb 14, 2021
Messages
55
Reaction score
18
Location
Erie, PA
The 3.7 wasn't a very good engine. My brother-in-law has one in his KK, ran into issues not running right. Read up on the valve seat problem, the lash adjuster problems, etc. Dealer said he needed a new engine due to carbon buildup, so no help there. My 05 CRD runs great with 180K. And the CRD's have the 545 ****** to handle the torque. Need the upgraded torque converter since I retuned the ECM for 330 ft-lbs as it will slip at lockup at lower rpms. Pulls great. We're not at altitude here, but I would expect it to do fairly well.

Good Luck
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,450
Reaction score
3,650
Location
Southeastern Ohio
1000s of 3.7s out there running hard daily
Not sure where the 3.7 wasn't a very good engine comes from ????
 

Michael Wolfe

Member
Joined
Feb 14, 2021
Messages
55
Reaction score
18
Location
Erie, PA
I would say just that design would allow the gummed up valve lash adjuster to allow the rocker arm to pop out and bounce around under the valve cover would be bad enough to warrant that badge. The valve seat failure is a bonus. I'd rather run the valve clearances myself than risk that. Maybe not as much of a problem if you maintain oil changes properly, but I've purchased only one car new over 30 years, and pretty difficult to determine how a used vehicle was maintained. I understand that there are aftermarket clip kits to prevent that from happening it's so common. I would hope there are still 1000's left, since the engine was in production for 10 years, in 9 different vehicle models. There were 1.2M Jeep liberty (KJ/KK) sold in the US alone, the vast majority were powered with the 3.7. The newer 3.7 pentastar 60 degree v6 has hit 10M units produced over 10 years, and no sign of retirement.
You must be registered for see images attach
You must be registered for see images attach
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,450
Reaction score
3,650
Location
Southeastern Ohio
2 of mine were used, only the 04 I bought new
On EACH used vehicle I buy all service records are required before I even test drive it, then I know for sure
If maintained well , not run hot , they last PERIOD !
If you buy a pig in a poke you get what you buy and nothing more
 

Michael Wolfe

Member
Joined
Feb 14, 2021
Messages
55
Reaction score
18
Location
Erie, PA
Please explain to me how it would show up on a service record if a previous owner overheated it pulling a trailer up a mountain. Please explain how it would show up if the owner's son liked to do burnouts when he had the vehicle. Is there a code stored on the ECM? If I blow a head gasket, and I replace it, where am I supposed to go to report that? Come on. You don't KNOW what happened to that vehicle before you bought it. Only what's been reported by the dealer, and believe it or not, there are actually some dishonest dealers.
 

Latest posts

Members online

Top