Hey guys, I’ve started a build that seems isn’t as common as I thought. I’ve got a 2011 2 door Jeep Wrangler that’s getting up there in milage (300k km). Currently has the stock 3.8/42re drivetrain, 4.10s and 37s. It’s driveable but anything over 80kmh and it really struggles. I’ve recently picked up an 03 LQ4 that will be paired with the 4l80 adapted to the stock rubicon tcase.

Posting here rather than the car forums because I have similar requirements to a lot of trucks. I need low end torque and reliability. I’ve compared trans gears between the 4l80 and my 42re, they are very similarly geared. On the highway I usually sit at 1600rpm@100kmh and 1900rpm@120kmh. Normally that would be great for milage except my 3.8 makes 200crank, it literally cannot push itself down the highway. I don’t plan to regear it because I’m very happy with the rpm range while driving and it wheels great with the 4:1 rubicon tcase.

I’ve added a couple pictures for reference. I’ll be taking the block and heads to a local machine shop to be hot tanked and decks checked and potentially resurfaced. It’s a low milage engine in great shape but sat for 10 years. Fired right up and ran great with some fresh fuel before it was pulled.

So I’m looking for recommendations on how to rebuild this engine to meet my needs. I’ve done some research on cams and it seems the biggest I would want is a 212/218 0.550” lift. Looking at BTR stage 2 and ls6 springs. I am definitely open to other suggestions but would like for it to be audible.

I’m still very much on the fence about pistons. Being an lq4 and staying n/a I would like to bump up compression a bit but want to stay on regular 87. Would a set of forged flat tops be worth the extra cash long term? I plan to eventually do heads, intake, and support mods but they will stay stock for now to ensure the swap goes smoothly.

I’ve done a bit of research on injectors but can’t find much other than “if you’re maxing them out upgrade them”. Which goes without saying for someone who’s engine is already in and running. Unfortunately I wouldn’t find out until everything is installed and potentially not running right due to fuel issues. Would the stock 25lb injectors be enough for such a mild build. I have seen a lot of recommendations on running the stock 8.1s which is definitely an option.

I’m very new to all of this engine building and horsepower gains, always been into stanced cars and wheeling mods. So any help here is greatly appreciated and will be huge.

 

your going to need more than 25s. I’m maxing out the 29.5s on my 6.0 and BTR stg2

 

Summit's new Big Truck Torkinator (SUM-8728R1) has an earlier intake valve closure compared to the BTR (33* vs. 37), so it would make torque earlier. The lift is more, so it'll require different beehive springs, but the Summit cam is much less expensive, so overall it's at least a wash if not still less. And the overlap is 2* more on the Summit, so it'll have the same if not slightly more lope.

If the pistons and cylinders are in good shape (sounds like they are), consider reusing them. They'll take quite a bit of power. Just get some new rings and gap them for any future plans you might have. If you want more compression you can have the heads milled.

 

I like the cam you picked out, any variation of 212/218 is a good choice IMO

You'll probably need at least a 32# injector

Just run 93 and be done with it. We're here for a good time, not a long time

Shoot for 10.5-11:1 compression

 

Personally I'd just stick the LQ4 in and see if you need anymore. It's already going to be a TON more power and torque than you've got now.

 

You always need more power and torque.

But seriously, I agree I'd rather do the swap first and then see how it runs before upgrades. I also would have verified compression on all cylinders, measured vacuum while running, and checked for diagnostic codes while still in the donor vehicle. And run it as is if it had checked out okay, rather than stripping it down. However, since he has already torn it down, and it was verified as running condition prior, I think it makes sense to go ahead and upgrade the valvetrain at this point.

 

Unfortunately I didn’t have a choice on weather it was torn down or bought. A close friend of mine had the truck so we pulled it for him. He tore it down after checking it and planned to do a high hp build for a drift car. His plans since changed and the tear down was as far as he got. Only paid $200 for all of it including the ecu and harness so I couldn’t pass on that

But that is exactly the reason why I would like to do some upgrades before reassembly. Though it’s also part of the reason I want to keep it such a mild build for now, money of course being the other because the damn kit is not cheap.

 

Look for some flex fuel injectors I’m running those on my 6.0 in my Chevelle with a 226/238 .600/.600 cam with 799 heads, have never seen them even get to 85% duty cycle shutting at 6500rpm.

 

I’d still throw it back together and run it. New bearings, new rings, deck the heads for some more compression. In something as light as that jeep, it won’t take much to see a huge difference. Not like it does in my k5.

 

You may also want to consider these cams from summit.

8727R1 https://www.summitracing.com/parts/sum-8727r1
8719R1 https://www.summitracing.com/parts/sum-8719r1

Or these from Texas speed.

https://www.texas-speed.com/p-8555-t...-camshaft.aspx
https://www.texas-speed.com/p-5002-t...-camshaft.aspx