Are you considering swapping the engine in your Jeep Wrangler for an LS/LT engine? This process can be complex, but with the right knowledge and tools, it can be a rewarding project. With experience drivetrain swapping 4 different Jeep Wranglers, I can let you in on some of the know-how before you get started.
Research and Planning
Before starting the V8 swap, it's crucial to do thorough research and planning.
First consider what model of V8 you were able to obtain, this is largely based on your budget. A used truck model LS/LT can be had for as little as $1000 before any rebuilt or modifications. A crate engine can run you anywhere from $3-4-5,000 to $25,000 or more. It all depends on how crazy you want to go.
I have always found that finding a good used engine and rebuilding it myself was the cost effective move, paying off in the end. If your budget allows, the crate engine option is the clear choice, giving more piece of mind.
Second consider what transmission, engine harness, ECU (GM or aftermarket), intake you plan on running. Each has positives and negatives.
www.rpmextreme.com is a great resource for engine swap knowledge, even if you dont go with an RPM extreme swap kit. I spent hours and hours on this page understanding what works with what, and what is best for my build.
The details are important here, learn all you can before you start.
For my 2008 Stretched JK Build I went with a 2017 GM LT 5.3 which I rebuilt with a Texas Speed Stage 1 camshaft among other supporting modifications. A 6l80e Gm transmission was utilized with a factory JK T-case. I wanted at least 6 gears for optimal gearing in different situations.
I went with this setup, because I knew it would make over 400 HP, and it was readily available in my area for a low price. Tuning was a pain, and if i were to do it again I would consider a stand alone engine management system for simplicity.
Custom Fabrication
Custom fabrication may be required to fit the LS/LT engine into your Jeep Wrangler. You will need new engine mounts, exhaust system, cooling system, hoses, and wiring harness. Precision and attention to detail are essential during the fabrication process to ensure a proper fit. Their is a lot of good information on this online, so read up what others have done and had success with. RPM Extreme makes some great OEM style engine mounts I was really happy with.
Upgraded Components
Upgrade various components in your Jeep Wrangler to handle the increased power and torque of the V8 engine. This may include upgrading the suspension, brakes, drivetrain, cooling and fuel system.
I recommend front and rear Dana 60 axles or better which will have upgraded brakes, and 1350 Drivelines. For cooling, a nice 3 row radiator with a proven pentastar fan handled all the Florida heat for me with zero issues.
Tuning and Testing
After the LS/LT engine is installed, it's crucial to tune and test the engine for optimal performance. Proper tuning ensures that the engine runs smoothly and efficiently.
This is a very tricky part that took a lot of patience, even working with industry professionals. If you choose a LT engine, know that due to the direct injection and cam phaser system they require " Torque Based" engine tuning.
Anyone who has ever assembled an engine has manually spun the engine oand felt the resistance and drag of all the moving parts. If you take a torque wrench, you can measure about how much torque is needed to rotate it. For an engine to idle you need to produce more torque, then the value of resistance or the engine will not idle. Going back to the rule of torque and airflow go hand and hand, as you can see we need to move more air to make added torque to overcome the friction. Not enough air and it won’t idle. Too much air and it will idle high.
When you decide to turn on the AC, you increase resistance to the engine and therefore need more torque to balance the output. The ECU commands the electronic throttle body to crack the blade and provide this air and make more torque. While this is an example of adding torque, much of the torque based control system is utilized to take torque away.
The transmission, traction control, and torque management all function by removing torque.
The transmission determines its shift patterns and characteristics based on torque as well. This information is transmitted from the engine controller to the transmission controller, which is why the engine calibration must be on point.
Consult a professional tuner familiar with GM Torque based tuning, and enjoy the benefits of direct injection.
Professional Assistance
If you're not confident in your ability to swap your Jeep Wrangler, consider seeking professional assistance.
Their are numerous companies that will swap your Jeep, and generally they tend to cost $25,000+ depending on how extreme you desire. Some well known brands in the industry are RPM Extreme, Brusier Conversions, Americas Most Wanted 4X4, and Motech.
Swapping a Jeep Wrangler is a challenging but rewarding project for enthusiasts looking to enhance their vehicle's performance after being lulled to sleep by the 3.6/3.8.4.0 engines of the past. After swapping multiple Jeeps, I will likely never have one with a factory engine again.. Its just too much fun.
Happy Swapping!