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Anyone running a Lq4 or lq9 in thier jeep?

42K views 151 replies 22 participants last post by  disturbedsledneck 
#1 ·
Just was curios what you thought of the power and what kind of driveline your running. If you made a harness or orderd one? If the 6.0l is that much better than an LS1 or a 5.3l? My friend has a 5.3l in his yj that he rebuilt and changed to Carb with a heathy cam, it runs good up top but not really impressed with the off idle respounce. For reference I run 38's with 60's front and rear (78' Ford w/4.88's) and plan on using a np231c hd and a 4l60e (wide chain) with a Tera-Flex super short eliminator as I allready T-case and it will bolt right up to the 4l60e, as far as I know. Any info would be great. Also did you do it your self or have someone else do it?

Thanks.
 
#3 ·
A 'healthy' cam, though could really hurt the low end ona small motor like a 5.3. I know the LS6 cams are popular as a cheap HP adder, but they cut out a lot of tq below 3000, according to the side by side dyno plots I've seen. Likewise, the factory intake is designed for low end torque. So he's probably lost a good 50+ft-lbs down there in the crawling ranges, which would put it not all that much above a 4.0...

The LS1 woudl be ~90 lbs lighter, due to the aluminum block, if it matters to you. Although aluminum block 5.3s (L33s among other), and 6.0s (LS2) exist as well.
 
#4 ·
Well I realy want an lq9 (6.0l) but have been thinking about the 5.3 for the money and the fact that a 5.3l came with a 4l60e and would'nt require any harness mods. I was also thinking the Ls1 as it to came infront of a 4l6oe (2wd would have to change output shaft). But I'm woundering if it's got anything down low such as the truck engines. price wise the ls1 has come down quite a bit, But I've heard that you need to switch the oil pan to a rear sump for starvation reasons.
 
#5 ·
I have an 03 6.0l out of an Escalade. That means cast block and aluminum heads. I used the factory harness & sent it out to be paired down for what I didn't want and at the same time had the ECM reprogrammed.

The rest of my drivetrain is a T350, stock 231 (yeah, I know) 4.88's running 39.5's. The motor makes good power pretty much throughout & don't have much to complain about. I can't give any input compared to a 5.3l.

Oh, you mentioned oil pan. I had to change to the corvette oil pan because the truck pan hangs way down.
 
#7 ·
I am doing a build with a 5.3 (6.0 would be great, but $$$). I think you will be happy either way. The 5.3 that your friend has probably lost alot by going carb., and big cam. All of the people I have talked to say the 5.3 works great and even better with some ecm tuning.

Keep us posted with what you decide.
 
#9 ·
anyone who puts a carb on one of these engines is retarded. properly tuned fuel injection will make a carb'd engine look like a gen 1 POS in any condition. it's people who dont know any better that put carbs on them and think they are doing some good.

if you want a lot of potential then go with the 6.0L, if you want up to 400hp then a 5.3L is a good choice. a cam that sounds cool at idle is bad for low end performance. if he were to put an adjustable cam gear on it he could advance it and get some of the low end back but he's already screwed it up with that carb.

I have a 6.2L L92 and I turned it into an LS3 be removing the cam phasing. I did some research and for a couple dollars more I can put the cam phasing back on and get more low end and top end than a fixed cam. a fixed cam engine takes the low end torque and turns that into horsepower on top when you put in an aggressive cam, a stock cam will keep the low end but you lose your peak HP numbers and get a flatter power curve. Needles to say I'm swapping to VVT and going with an aftermarket cam. 530hp with more torque on the bottom end than a stock engine. :thumb:

the truck intake flows better than the car intake, keep it on if you can and dont go too crazy with a cam, less is more when you arent operating in a 1000 rpm window.
 
#13 ·
Thank you for your responces. Whiterino how do you like the 4.88's and 231, also did you run the corvette oil pan so that you could keep the truck intake. I ve heard alot of people say that the truck intake is better for torque than any other.
Any opinions on the hole Lq9 vs Lq4, I know the differences between the two engines but for a jeep is the Lq9 that much better? Opinions?
 
#18 ·
the only difference between a lq4 and lq9 is some compression and about 30hp... most of that can be accounted for with a tune because one compressions point alone is good for 4hp IIRC, it's what you do with the higher compression is where one shines over the other. IE, higher octane fuel enables you to advance the timing more and timing is power. either engine will get you well over 400hp with the right mods and tune.

Mine is a 2500 pound paper weight right now but I have a th400 and 3.8:1 atlas with 4.88's and 37's. when it moves on it's own I'm pretty sure I have the gearing nailed for the power. I do plan to swap in a 4l60,65 or 70 in place of the 400 and at that time I'll probably do a 4 speed atlas at the same time for no real reason other than I want more gears.
 
#16 ·
Haggar, not sure what you mean by batwing pan. The pan that came off was aluminum as was the one that went on. They are totally interchangeable, just the corvette one is not as deep. I think it changes is from an 8 quart capacity to 5. I also changed the baffle splash plate inside although I don't think I actually needed to. The corvette oil pan had nothing to do with the truck intake. There's no relationship there. I did it purely to keep the pan from getting smashed on a rock.

RE the 231 and 4.88's, the ratio is pretty good for general low range wheeling. With my current tire size, it's a damn good hill climber in low range but is a little too aggressive on rocks & stuff and there are times I wish I was closer to 4:1 instead of the 2.7:1. A new T-case is in the plans for the future. I have previously cracked a couple 231 cases but I beefed up the current case & haven't broken it since. I had also broken the front output shaft but ever since I went to a 2 pc carrier style front drive shaft I haven't had a problem. My theory is that with the shaft coming straight forward to the carrier bearing that I'm not putting any side load on it which helps it to survive. I'm totally aware that it's a weak link which is why I carry a complete spare T-case in my trailer.

BTW, if you get a new enough engine that has the throttle by wire, make sure you get the pedal, wiring harness and module from the same donor vehicle. Ask me how I know.:(
 
#17 ·
Yeah I know the 231 isn't the best t case for crawlin thats why I wanted to go with a four speed trans so I can ge a lower first gear. Pertaining to the intake, I've heard of people having trouble with hood clearence because of the rather tall truck intake. As per the throtle buy pedal do you find it touchy off road?
 
#22 ·
mine will be DBW unless I have a problem with it. I will be making a starter tune to make it run but for the final tune I will be modifying the harness myself and having vector motorsports do the tune on their chassis dyno.

Jims performance is great for a standard tune for something like a stock engine. I will have an after market cam and cam phasing so it needs a lot of fine tuning. a tune and dyno time from vector is about 500 as where jims charges about 400 for a tune and a harness that is plug and play.
 
#29 ·
I have an LQ9 in the WTF-J. It sits in front of an 4L65e and an Atlas TC. I put in the GMPP "Hot Cam" and love it.

I stayed with the truck intake/pan and have plenty of room under the hood and clearance (See the third pix with the crossover and note the location of the front diff/drive shaft. The oil pan is not the low point by any means.)





 
#32 · (Edited)
The VSS is in a housing between the trans and the T/C. It works, but in low range the speedo goes nuts. (You can see the VSS housing in this pic.)



Yup, single exhaust. 2.5" collectors into a 3" single system. I put a bung for a wide band in the root of the Y pipe where it transitions to 3".

 
#35 · (Edited)
Did you put the o2 bung in place of the two that are typical in a swap or are you running three for tuning reasons?
Three. (Two pre-cat and one WB. The WB isn't in yet; that will be a later upgrade.)

Yes, the Atlas was the six bolt hex pattern.

The powertrain came from Schram and was out of an '06 Escalade w/500mi. It included the trans, and was a great way to buy all the pieces and parts as it included the ECM, DBW TAC, starter, alt, harnesses, etc.
 
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