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Higher horses, higher revs & even higher torque, a streetable LJ engine swap

toximus

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"Never let someone tell you that you don’t need more horsepower. Just stop talking to them, who needs that kind of negativity in their life?"

If you missed the main phase of my build, you can find it over here: High travel, high clearance & high octane, a streetable adventure LJ story. I'm still posting non-engine related build updates over there so if you're interested in that type of thing too I suggest you follow both threads!

Ever since I rode along in some Jeeps desert racing and put the supercharger on my Jeep I've turned into a bit of a horsepower junkie. Because ending an addiction is no fun, my methodology here is to throw the biggest, baddest, strongest engine (that doesn't compromise my main build goals) under the hood of my LJ and not be left with wanting anything more.

Unlike the main phase of my build which I received a lot of direction on from MrBlaine and was able to base my build on many many iterations done before mine, this engine phase of my build I'm going to be upfront that I have little to no clue what I'm doing. Don't tell anyone but the most engine speak I do is smiling and nodding when guys talk about their engine's lift, timing, compression, litres, etc -- yeah, I have little to no clue what any of that means. HP/TQ charts are about as far as I understand. I'm sure as I do this engine swap that there will be things that work well, things that could be done better but aren't worth redoing, and things that need redoing. This is new territory for me.

My goals are:
  • Reliability is priority.
  • Not compromising phase 1 of my build is non-negotiable.
  • Cramming as many ponies under the hood as I can.
  • Torque and HP curves need to work well for my uses and not focus solely on peak horsepower.
 

toximus

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Here's an overview of the Jeep this engine will be going into. (Full details on my build thread: https://wranglertjforum.com/threads/...lj-story.9956/)
  • 37" MTR tires on 17" TrailReady beadlocks.
  • RockJock 60VXR axles geared to 5.38 front and rear with ARB lockers, RCV front shafts, load bolts, and full floating rear.
  • 14" Fox coilovers front and rear with 7" up and 7" down at an equivalent lift height of 4"
  • 105" wheelbase which is ideal for my tire size
  • Savvy mid-arm 3/4 link.
  • Tucked skids
  • All aluminum armor and synthetic winchline to keep weight to a minimum
  • 4860lbs fully loaded.

20200508_completed-build.jpg
 

SLOWPOKE693

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I followed your build on the other site. That Jeep is cleeeean, and you definitely gots the OCD. :smokin:

I'm looking forward to seeing the next phase!
 

toximus

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I followed your build on the other site. That Jeep is cleeeean, and you definitely gots the OCD. :smokin:

I'm looking forward to seeing the next phase!

I'm glad to have you following!

She's not quite as clean as it looks though. Some day the torque boxes are going to rust through. :'(
 
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gt1guy

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Are you going to stay with an LS engine?

If so, just throw a LSX454 in there. It's a factory crate engine so the reliability is there and it makes stupid power.
 
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Thanks for starting this. I followed the other one and was hoping you would pop up over here. I dig your attention to detail. Ill be looking forward to the Engine progression!
 

toximus

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Are you going to stay with an LS engine?

If so, just throw a LSX454 in there. It's a factory crate engine so the reliability is there and it makes stupid power.

I'm currently running the stock 4.0L with a supercharger. The supercharger hasn't worked right since day 1 and despite months of talking to the company that sells them (BoostedTech has been unbelievably unhelpful) I've gotten nowhere as far as solving the problem.

I haven't bought a motor to swap in yet, but I'm leaning strongly toward the LS.

Since I'm not wanting to work on the motor aside from easy stuff like bolting on accessory brackets, do you know how much work a LSX454 takes to finish off?
 

toximus

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Thanks for starting this. I followed the other one and was hoping you would pop up over here. I dig your attention to detail. Ill be looking forward to the Engine progression!


I thought about copying my other thread over here but it seemed like it'd just be confusing. Instead, I linked to that build thread on a different forum instead of *irate.
 

gt1guy

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I'm currently running the stock 4.0L with a supercharger. The supercharger hasn't worked right since day 1 and despite months of talking to the company that sells them (BoostedTech has been unbelievably unhelpful) I've gotten nowhere as far as solving the problem.

I haven't bought a motor to swap in yet, but I'm leaning strongly toward the LS.

Since I'm not wanting to work on the motor aside from easy stuff like bolting on accessory brackets, do you know how much work a LSX454 takes to finish off?


My mistake, I remember seeing posts about your blower and just assumed you had an LS.

The work it takes to finish off the LSX454 would be the same as any GenIV LS engine. I'd think you could just run it standalone in a TJ, but I'm sure there are others here that are more switched on about TJ swaps. I know Dookey may have some insight. Maybe a call to PSI Conversion (732-444-3277).

I'd run a 6l80/90 trans with it. You're already running a auto trans correct?

Need to make sure the rest of your drive train is up to the task of 627hp and 586 ft/lbs. That's a lot of torque. GM also makes crate LS3 engines in 525hp, 480hp and 430hp, along with all the other stock replacement engines for cars and trucks.
 

toximus

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My mistake, I remember seeing posts about your blower and just assumed you had an LS.

The work it takes to finish off the LSX454 would be the same as any GenIV LS engine. I'd think you could just run it standalone in a TJ, but I'm sure there are others here that are more switched on about TJ swaps. I know Dookey may have some insight. Maybe a call to PSI Conversion (732-444-3277).

I am thinking a NA engine might be a better choice for me after my negative supercharger experience which was impossible to diagnose the issue of without throwing parts at it. I'm also not sure that an intercooler will stack behind the grill along with my large steering and transmission coolers, engine radiator, and AC condenser. If the typical radiator space behind the grill is an issue I could also place a cooler with a fan blowing up through a hood vent on top of the engine.

I'd run a 6l80/90 trans with it. You're already running a auto trans correct?

I am currently running the stock automatic and I plan to stick with an automatic. The 6 speed would be awesome for having a nice range of gears in low range. I don't want to loose any belly height and the 6L80 is deeper than the 4L70 so I need to make sure that'll be fine before spending money.

Tap shift could be fun but not a requirement, and I don't need a manual valve body.

Need to make sure the rest of your drive train is up to the task of 627hp and 586 ft/lbs. That's a lot of torque. GM also makes crate LS3 engines in 525hp, 480hp and 430hp, along with all the other stock replacement engines for cars and trucks.

My axles should be fine and I will be replacing the transfercase too so I think it'll all hold up.

GM also makes crate LS3 engines in 525hp, 480hp and 430hp, along with all the other stock replacement engines for cars and trucks.

The crate LS3 seems to be a very easy engine for me to wrap my head around and there's a ton of knowledge of it on the LS forums if I ever do have issues. I'm sure there's plenty of reputable engine builders across the country that I could also go to that could help me with any LS3 issues too. And, at least on the surface, it seems to fulfill my requirements. I did notice a few companies are stroking the LS3 to make 600-700hp NA for Ultra4 but I don't know how those will hold up after 20 years and 200k miles. I also don't want to be tied to a single company to support a stroked LS3 when I inevitably will have an issue.

I could totally be off base here, this is just my ramblings...
 
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gt1guy

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The LSX454 and the three LS3 crate engines I mentioned are all NA.

I honestly don't know about the warranty on the LSX, but the LS3/525 I put in my Jeep came with a 2yr/24k mile warranty. There are literally thousands of folks DDing LS crate engines. I'm sure it's the same for the Ford and other crate engines.

As far as stroker engines go..................you ain't getting much bigger than 454ci.
 

toximus

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The LSX454 and the three LS3 crate engines I mentioned are all NA.

I honestly don't know about the warranty on the LSX, but the LS3/525 I put in my Jeep came with a 2yr/24k mile warranty. There are literally thousands of folks DDing LS crate engines. I'm sure it's the same for the Ford and other crate engines.

As far as stroker engines go..................you ain't getting much bigger than 454ci.

Have you been happy with the LS3/525? Anything you'd do differently? Reason for suggesting the LSX454 vs the LS3/525?
 

gt1guy

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Have you been happy with the LS3/525? Anything you'd do differently? Reason for suggesting the LSX454 vs the LS3/525?

I haven't started my LS yet.....................................and the 2yr warranty has passed already. I'm a bit slow on my build.

I mentioned the LSX454 cause it sounded like you wanted stupid power.................................that engine makes stupid power.

I went with the 525hp version for a few reasons. One was it had the best looking torque curve of the three LS3 crate engines (430/480/525 HP). I have a 4dr JK, so I'm moving some weight. I wanted an engine that I wouldn't wish I had more power two months after I got it running. I wasn't looking for stupid horse power.

I know someone who put a 525 in his 2dr JK and he had nothing but good things to say about it. When he got it dyno tuned, I believe it was putting 360hp to the wheels.
 

toximus

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I haven't started my LS yet.....................................and the 2yr warranty has passed already. I'm a bit slow on my build.

I mentioned the LSX454 cause it sounded like you wanted stupid power.................................that engine makes stupid power.

I went with the 525hp version for a few reasons. One was it had the best looking torque curve of the three LS3 crate engines (430/480/525 HP). I have a 4dr JK, so I'm moving some weight. I wanted an engine that I wouldn't wish I had more power two months after I got it running. I wasn't looking for stupid horse power.

I know someone who put a 525 in his 2dr JK and he had nothing but good things to say about it. When he got it dyno tuned, I believe it was putting 360hp to the wheels.

Gotcha.

My heart is telling me to choose stupid horsepower but like you my brain is telling me to choose enough that I won't wish for more.

I guess I need to figure out what realistically is my upper limit from a usable, controllable and being able to keep it cool perspective. I want incremental power and good control in technical offroad stuff. I don't want so much power that tapping the throttle lights up the rear wheels on the highway like a hellcat. If the LSX 454 is that, it'd be fun but only until the first road trip... I'd be curious how the LS3/525 in the 2dr JK is, unless he's running armor I'd guess it'd be similar in weight to my Jeep.
 

gt1guy

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Well, if you think about it, nobody in the 5.3LS swap thread on the other site ever said their rig ran like a dog. I think most of those engines are around 325-350hp stock. Almost all of the engine swaps on JKO were done with the 6.2L 430hp LS3 crate engine, or a 5.3 out of a truck. Some folks with heavy 4drs that did the 5.3L said they wished they had gone with the 6.2L. Nobody that did a 6.2L ever said they wished for more power.

With all that said, the 200hp minivan engine that came in the JK's is a pathetic under powered dog. The newer 3.6L engine puts out 300hp and gets fewer complaints.


The hardest part is being honest with yourself about power goals.


I figured there'd be a whole bunch of folks chiming in with their thoughts in here.
 

toximus

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Well, if you think about it, nobody in the 5.3LS swap thread on the other site ever said their rig ran like a dog. I think most of those engines are around 325-350hp stock. Almost all of the engine swaps on JKO were done with the 6.2L 430hp LS3 crate engine, or a 5.3 out of a truck. Some folks with heavy 4drs that did the 5.3L said they wished they had gone with the 6.2L. Nobody that did a 6.2L ever said they wished for more power.

With all that said, the 200hp minivan engine that came in the JK's is a pathetic under powered dog. The newer 3.6L engine puts out 300hp and gets fewer complaints.


The hardest part is being honest with yourself about power goals.


I figured there'd be a whole bunch of folks chiming in with their thoughts in here.

I've always been surprised how few people chimed in on my build thread...

Researching the engine swap this past week there's a lot more JK info than there is TJ info. To get good data points I've been cruising the JK forums quite a bit. We don't see as much high HP swaps being done over on the TJ forums -- mainly the junkyard 5.3.

I will say that the supercharger on the stock 4.0L (giving around 250-260hp at the crank) was enough to be content with (but admittedly more power would have been even more fun). If it didn't have problems I probably would have tinkered a little bit with higher boost and roller rockers and then left it as is. Since that didn't work out, the excuse to swap was justified and I want to make sure I'm not left wanting more. If the TJs came with the late model JK engines I doubt there'd be many TJ engine swaps at all.
 

toximus

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During this dreaming phase I have mulled over many different ideas from the different forums and phone conversations ranging from Hemis which would interface easier with the existing dash electronics, a high horsepower SRT8 Hemi, 1000hp turbo LS, dash ideas, cheap junkyard LS engines, different transmissions, Hellephant engines, exhaust header configurations, various wiring concerns, diesels, turbos, etc etc etc. Somebody even mentioned a '98 Honda Civic 4-banger! 🤷‍♂️🤣

To help unmuddle the mixture I got in touch with a guy who does engine swaps for a living and has worked with both the Hemi and LS, he's been kind enough to answer some questions for me and point me in the right direction.

The best advice I received is to do a proven engine swap that's been done before and not be the first to do something. Because reliability and actually getting my Jeep running sounds good to me, this seems to be advice that I'll be following throughout the entire swap even if it means missing out on something new and cool.

From the sounds of it, the LS engine is going to have the best bet of fitting into my build.

All of the Jeep interior stuff will function as long as they're powered up with 12v. The airbags, wipers, lights, turn signal, hvac blower, radio etc do not require the PCM.

If I want the factory gauge cluster to work with an LS then I will need to make a special harness that incorporates the GM side with the Jeep side PCM. However the easiest, most reliable and problem free solution will be aftermarket gauges that will interface directly with the GM ECU.

Even though I will be going with an LS I expect most of what I post about packaging the engine and trans will apply to any high uptravel builds where a high pinion axle housing travels up into the engine bay.
 

gt1guy

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If I'm not mistaken, TJ's are generally getting Gen III LS engines installed and the JK's are getting the Gen IV and V LS engines. Big difference being Canbus or no Canbus.
I'm getting to the limit of my knowledge but, as I understand it, it's easier to swap in the newer engines into the JK's because all they needed was a box that converted GM language to Jeep language to get al the dash features to work. The older engines were a nightmare to play nice in the JK's.

But I don't understand the TJ's not using the newer engines with a standalone harness. Maybe it's a old habit thing.
 

gt1guy

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So there's still a communication issue with the TJ's dash. I did not know that.

Check out Dakota Digital, they make some nice gauge clusters that plug into the GM OBDII ports.
 

toximus

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Yeah, there's no great dash options for the TJ. You can either run a second set of sensors or use aftermarket gauges. I know Alexa is working on something though. I'll probably cut a plate to fit in the dash and mount gauges and lights in it.

If there ever is a cleaner option I'd switch the factory dash back since I think it looks a lot nicer.
 

toximus

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I made my mind up!

I chose to go with a V8 Chevy LS3 6.2L 495hp crate engine. If I ever want more power I can top it off with a Maggie supercharger to make somewhere around 630hp on pump gas or build up the internals to make more power naturally aspirated. If it's too much power I can replace the hot cam with the regular cam to make 430hp.

nal-19370416_xl.jpg


How I chose this horsepower is the equation that more horsepower = more better. ...at least up to a point... At some point there is a $/HP wall that's expensive and with cheaper power adding mods you run the risk of pushing the engine too far and causing reliability issues. I also have concerns of the throttle being too touchy for slow speed crawling or accidentally spinning the tires on the highway. When you take into account the power to weight ratio of my Jeep and the power required to rotate the 37" tires I think 495hp will start to balance out nicely. My power to weight ratio will be about 1hp:9lbs. In comparison a stock TJ has a ratio of 1hp:18lbs, a 2dr JL is 1:14, a Ford Raptor is 1:12, a Polaris RZR turbo is 1:11, a sports car or top model Jeep STR8 is in the 1:7 range. With my deep 5.38 gears in the axle I probably won't be winning any 1/4 miles but real world driving should be excellent on road and off road.

I did not go with the 530hp crate engine with the ASA cam because the hp/tq chart shows that more power is created at the higher rpms and not as much at the low end like the 430hp and 495hp crate engines do which isn't ideal for me. The lopey cam sounds awesome with good chop but I don't want to have trouble with a low idle either.

The other runner up I considered is the LSX 454. It has 130hp more than the LS3 I chose at the cost of being 150lbs heavier due to having an iron block. In the end I had concerns that it'd have too much power and act more like an on/off switch than incremental throttle, that would only be fun until the first road trip...

I ended up deciding on the crate engine vs junk yard after looking at various used options and finding that the good low mile stuff went before I could nab it. With the crate engine I won't have to worry about preexisting issues, damaged parts, or having to mix and match the best of different stuff together to make the engine the way I want it. From what I've researched mixing and matching different electronic bits from different models and years can also cause electrical connector confusion and ECU reprogramming. Since I'm not familiar with the LS platform that sounded like more than I am willing to take on. What isn't great about the crate engine is that it's not complete and I'm going to have to figure out what's "missing" and finish off the engine.

The LS3 engine is made from aluminum and weighs approximately 100lbs less than the Jeep 4.0L that's coming out. So that's pretty cool!
 

SLOWPOKE693

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Good choice, but your going to hate it with 5:38's. That's what's going to make it an on/off switch. Your probably going to want to consider 4:56's or 4:88's down the road.
 

toximus

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Good choice, but your going to hate it with 5:38's. That's what's going to make it an on/off switch. Your probably going to want to consider 4:56's or 4:88's down the road.

Hmm... Ideally I need to figure that out now before ordering the transfer case.
 

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Once you figure out what you need for accessories to complete the engine, let me know. I have a ton of brand new LS accessories sitting on the shelf for a build that didn't happen.

-Mechman alternator (160 amp)
-Goat built accessory brackets
-PSC pump with appropriate sized pulley
-NIB GM truck water pump
-NIB GM truck harmonic balancer
-Pac Fab LS oil pan with skid plate
-Some other shit I cant remember... lol
-Rock Tactics LS motor mount kit

I bought alot of it from Goat Built for a customer of mine, in anticipation of picking up the 525hp crate engine for his buggy build. He had some life stuff come up so I bought all the parts off him and have been sitting on them since.
 
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toximus

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Once you figure out what you need for accessories to complete the engine, let me know. I have a ton of brand new LS accessories sitting on the shelf for a build that didn't happen.

-Mechman alternator (160 amp)
-Goat built accessory brackets
-PSC pump with appropriate sized pulley
-NIB GM truck water pump
-NIB GM truck harmonic balancer
-Pac Fab LS oil pan with skid plate
-Some other shit I cant remember... lol
-Rock Tactics LS motor mount kit

I bought alot of it from Goat Built for a customer of mine, in anticipation of picking up the 525hp crate engine for his buggy build. He had some life stuff come up so I bought all the parts off him and have been sitting on them since.

I will probably take you up on the GoatBuilt brackets and alt. I was actually going to call Drew tomorrow for them. Do you remember which part # they are? Send me a PM with what you've got.
 
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