5.3, 6.0, 6.2...which one should I go with?

I would try and get a aluminum block, with that said the 5.3 can make some good power. But you will have to mod it to get to the levels of the 6.0 or 6.2 stock.

I have seen 5.3's make some really good power with not a lot of work, when I was into drag racing LS motors were the thing to mod.
 
I have the 6.2 and love it. It idles at 600 rpms all day and matched with the 6L80 tranny is sweet. It's like driving a corvette but you are in your jeep. You can't go wrong and Robbi is awesome to work with.

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Rhynojku said:
I'm blessed to be able to make this decision. Rod started knocking only got 61k and now I don't see any other options. What are current ls runners opinions?
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Here's a link to a similar thread. A lot of good info to base your decision on. :beer:

http://wayalife.com/showthread.php?38811-Which-LS-is-for-you-(Or-me-)

MOTECH said:
After supporting about 200 swaps here is my opinion. I will limit this the Gen IV engines since they are emissions compliant and make the most sense in a JK. I will also assume you are running a 6l80 transmission since it is very strong, adaptive, low friction, low heat , inexpensive and available. The 6l80 has a 4:1 first gear and .6 OD which is key to performance, economy and gearing. Guys with 5 speed Chrysler transmissions think they work great compared to the 4 speeds, then drive a 6l80 and feel the difference.

With such a low first gear you can run one size taller gear and still launch a heavy JK hard; then cruise 2,000 rpm @ 70 mph getting reasonable fuel economy in the second OD gear.

There are 3 basic engines to choose from based on performance vs cost, the 5.3, 6.0 and 6.2.

While a great engine the 5.3 is usually not the best choice for our JK's. The 5.3 is only 1.5 liters larger than a 3.8 and has less torque than the other engines. Torque is what hauls your JK around, up hills, fighting headwinds, high altitudes, etc. The larger displacement engines simply have more torque; this means they are more efficient in heavier JK's.

Going to Moab @ 70 mph at 7,000 feet fighting a headwind up a hill is a lot of load on the powertrain; especially in a lifted JK with a lot of drag. The 5.3 will hold the speed but it will downshift, it will go open loop into performance enrichment. This means the 5.3 is spinning faster and running richer, approximately 12:1 in OL.

A 6.0 or 6.2 will hold a higher gear spinning the motor slower, the engine will stay in closed loop running off the O2 sensors with an AF of about 14.2:1. Would be about 14.7:1 but we run alcohol in the fuel so stoich is a bit lower. In the end the larger engine is more efficient in a heavy JK as well as more pleasant to drive without the downshift. A 40" wheel/tire combo can weigh 200 pounds x 4 = 800 pounds so available torque is critical.

So is the 5.3 useless - no. In a light JK with minimum lift and 32" Rubicon wheels and tires the 5.3 is great and can return 20 mpg on the highway. The key is light and low drag, plastic fenders, bumpers, etc.

Intermission
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MOTECH said:
When it comes to the 6.0 and 6.2 they will both get the job done, it comes down to performance vs cost. The truck 6.0 is built to haul weight, and it will do it on regular gas (like the 5.3). The 6 liter engine has an iron block and is almost bulletproof. The 6.0 is a great expedition engine because it runs on almost any gas and can be abused. The 6.0 engine is inexpensive and readily available.

The all aluminum 6.2's are a step up in performance and cost. With high compression heads and all aluminum construction they are designed for performance and turn your JK into a mild muscle car. The 6.2 engines require premium gas, synthetic oil and cost more than the other engines. The flip side is all the 6.2's are over 400 HP and fun to drive.

Amongst the 6.2's is the truck and passenger car engines. The truck engines have a little more bottom end and less HP while the LS3/L99 have more top end and higher power band. If you drove any 6.2 most of us would think it is enough if not too much HP.
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cozdude said:
IMO it depends on what type of build you have and what type of power your trying to accomplish.

I know for me if I had the option I would do a 5.3 for my 2 door. Why? Because my jeep is a lot lighter and doesn't need the power of a 6.2, I don't plan on going larger than 37's, and it would prob be more cost effective.
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Bet you could Shoot the Moon better with a 6.2!
 
I want a 6.2....hmmm I'd sacrifice and swap you my 3.8 for a 6.2, I can deliver it to motech to have them install the 6.2 and remove the 3.8 that way you would know it was done right
 
aldaman said:
Here's a link to a similar thread. A lot of good info to base your decision on. :beer:

http://wayalife.com/showthread.php?38811-Which-LS-is-for-you-(Or-me-)
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I read something MoTech wrote, somewhere, that the 6.0 produced 400 hp, and runs on regular gas. The 6.2 makes 430 hp. Depends on what you want, & how much you want to spend. For me, 400 hp on regular gas, and a less expensive engine, will be the way I go, one day.


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Coming from someone who has had both a 5.3 in a chevy pick up and a 6.2l LS3 it's all in what you want. If you want a lot of power go with the 6.2. If you want moderate power, 5.3. My 5.3 had a hot cams camshaft and was laptop tuned. But only pushed around 412 HP.
 
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