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Dream big? 4.7 I6 super/ turbocharged or a GM 5.3?

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KarmaKannon

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Utahhhh
!!!1 time!
You have a fun jeep that is your smallish families extra vehicle/ recreation/ light trails or blasting around the desert. It needs to be streetable and reliable enough to drive to work daily or go run kids around to school or whatever in the event one of our other vehicles goes down or gets torn apart for surgery or I decide my truck is boring. This is not a trail rig and it isn't drag vehicle, but running the street legal drags or a trip to Moab for light trails wouldn't be out of the question. What would you do and why?

Assume that I am talking about a 4.7 stroker inline 6 with forged pistons, scat crank, scat rods, bigger cam, and ported head, and some forced induction. Now assume I have the stroker already and would only be adding the forced induction.

V.S. :firedevil
A gm 5.3 v8 swap with nothing more than headers, slightly bigger cam, and maybe cleaned-up heads.

The stroker 6 with forged induction is good for what? Maybe 325-350hp or maybe as much as 400hp if you get really froggy?
The 5.3 is good for about 350 with a bigger cam and some smallish mods.

The cost of forced induction for my stroker is anywhere from $2,000-$5,000 I'm guessing.
The cost of a 5.3 swap is $3,000-$4,000 I'm estimating, but I would also subtract the price of selling my stroker.
 
LS, no question…

All that time and money into a clapped out tractor motor still running flat tappet lifters to HOPEFULLY make what even a run of the mill LM7 does out of the box? No thanks.

Horsepower per dollar, LS. Reliability at comparable power levels, LS. Weight, LS.

Boost a blingy stroker and cry at the cost of any repairs down the road. Pulling out an LS and dropping in a new one is a $500 trip to the junk yard and a weekend worth of work.

The only argument I could see for keeping the I6 would be for emissions in one’s state.




Oh, and you’ll never get the same sound out of the I6.
 
I agree.

I6 not worth putting money into beyond building it for reliability

Sent from my SM-G960U using Tapatalk
 
Well... I came here for a sanity check and so far I've gotten one. I would argue that a slightly modified 5.3 xj will be a better daily driver than a forced induction I6 stroker too. Better gas mileage, more reliable (likely), and likely a better power band for passing.

The I6 has a unique, and I'd say nice sounds. The v8 would sound better now doubt.

I also have a nice stroker to sell and get back some of my money for the swap. The stroker has been far from cheap, but that's an entirely different story. I could have done a used 5.3 swap for what I'm into the stroker. It's not exactly a budget build, and it's not top dollar everything.

The transmission is the biggest issue. I'll leave a teaser pic right here. I think it's viable go keep the aw4. I also have a fall back plan to use the 4l60e. Time to sell my prerunner and start buying parts.
PXL-20210707-020358939.jpg
 
IT's fun and all to talk about engines, but what's your tranny situation? If going the LS route a new trans, transfer case, and driveshafts are needed. Assuming you now have an AW4, it wouldn't last long behind a boosted stroker unless you fully built it up.

So dollar for dollar with everything considered, the LS is the better option in the long run. I just hate how the radiator and headers are so damn expensive for the conversion.
 
Emissions isn't a huge concern, although it was my reason for not doing the swap before the stroker build. My family has a place in Idaho and I could likely register it there if I have issues with the plug in OBD2 test they do here. My dad did that with his diesel because he got tired of the government monopoly on diesel emission testing.
sandfreestyle said:
IT's fun and all to talk about engines, but what's your tranny situation? If going the LS route a new trans, transfer case, and driveshafts are needed. Assuming you now have an AW4, it wouldn't last long behind a boosted stroker unless you fully built it up.

So dollar for dollar with everything considered, the LS is the better option in the long run. I just hate how the radiator and headers are so damn expensive for the conversion.
Click to expand...

I was planning to try and use a modified aw4 for either option. The 4l60e is a fallback plan. Lengthening shafts and such isn't a huge concern. It does add to the nickel and dime stuff though. The bigger concern is the added cost of a trans controller for the 4l60. I was thinking the aw4 would work without a controller for light duty work in case the wife drives it and just go to manual controls for my usage.
 
Can the AW4 even be adapted to an LS? I know Novak doesn’t offer products and seriously discourages it.

4L60 or 4L80 are the easy candidates. Typical 6 bolt round pattern, use what ever transfer case you like. If money is no object, I would suggest looking into the 6L80.

Manual options have come a long way too. LOJ conversions offers an an adapter and clutch package for the nissan VQ40. It’s comparable in strength to a T56 at a fraction of the price, with 4x4 options.
 
I have an aw4 sitting here. Its sitting here because I found no beef parts to throw in it. Like billett tourqe converter.
I was thinking about manual to auto swap

4l6e is baddasery something has to spin it myswell be a 5.3

Sent from my SM-G960U using Tapatalk
 
VAhasnoWAVES said:
Can the AW4 even be adapted to an LS? I know Novak doesn’t offer products and seriously discourages it.

4L60 or 4L80 are the easy candidates. Typical 6 bolt round pattern, use what ever transfer case you like. If money is no object, I would suggest looking into the 6L80.

Manual options have come a long way too. LOJ conversions offers an an adapter and clutch package for the nissan VQ40. It’s comparable in strength to a T56 at a fraction of the price, with 4x4 options.
Click to expand...

Can they? I think it can be done. I plan to try a bellhousing adapter with aw4 torque converter and spacers. Maybe the 4l60 bellhousing is a better choice and then I adapt it to the aw4 trans. Not sure yet.

Novak doesn't offer much in the way of explanation for the lack of aw4 adapters. From their site.
"The AW4 automatic is a stronger transmission, but its computer controls, funky shift points and overall quality when compared with the GM Hydramatics makes it a sub-par choice. The AX15 manual transmission, however, can be successfully retained in a GM engine conversion"

Sounds like it's more of a tuning or lack of tuning support issue rather than a strength or packaging issue. Full manual controls over and aw4 might negate much of the issues and allow me to keep my trans/ transfer case/ wirirng mostly stock.

I like manuals but there's little chance my wife will drive it if it's manual. I also don't like driving traffic with a manual.
 
If I can adapt the aw4, the conversion could be $1,000-$2,000 less expensive. That's huge in a $4,000-$6,000 vehicle. I'm not against a 4l60e and the donor vehicle I'm trying to get has one anyway. I just don't like the cascade of parts and issues when I put a 4l60e inside a jeep that wasn't wired for it. It's not twice as much work as the engine swap, but it's a big part. If I can't get the aw4 to work, then 4l60e goes in.
 
If you already have a donor car then keeping the 4L60E is easy peasy. The XJ computer (retained as a gauge mule) won’t care at all about no longer receiving data from the transmission. You can really just retain the GM harness with the TCM fed into the GM computer so there is nothing to invent or bridge.

From my experience your cost estimate of 4-6k for the GM swap is reasonable if you already have a donor car, if not then it will be more expensive.
An adequate radiator will be $700, fuel management $300, plumbing $200, Novak wiring harness $700, make your own harness and it will still be $300 in sensors and wire and loom. You will
Need a shifter $400-600, if you care about your tachometer the conversion module is $200, depending on your donor you may need an oil pain $300 (LM7 oil pan was perfect for my swap), air filter components $200, transmission tcase adapter $300, transfer case shift linkage (your stock one will not fit with the GM transmission) $270. You will likely need new accessory brackets to fit in the skinny XJ engine bay. If you donor isn’t a car and you don’t want to mess with your hood you will need a car intake as well. Reprogramming the GM computer for anti theft $200.
That’s a lot of nickels and dimes and there are others that I’m forgetting. It adds up quick.

Definitely better than inventing a way to keep the aw4 and likely much more reliable than a built stroker.
 
Skruffy said:
If you already have a donor car then keeping the 4L60E is easy peasy. The XJ computer (retained as a gauge mule) won’t care at all about no longer receiving data from the transmission. You can really just retain the GM harness with the TCM fed into the GM computer so there is nothing to invent or bridge.

From my experience your cost estimate of 4-6k for the GM swap is reasonable if you already have a donor car, if not then it will be more expensive.
An adequate radiator will be $700, fuel management $300, plumbing $200, Novak wiring harness $700, make your own harness and it will still be $300 in sensors and wire and loom. You will
Need a shifter $400-600, if you care about your tachometer the conversion module is $200, depending on your donor you may need an oil pain $300 (LM7 oil pan was perfect for my swap), air filter components $200, transmission tcase adapter $300, transfer case shift linkage (your stock one will not fit with the GM transmission) $270. You will likely need new accessory brackets to fit in the skinny XJ engine bay. If you donor isn’t a car and you don’t want to mess with your hood you will need a car intake as well. Reprogramming the GM computer for anti theft $200.
That’s a lot of nickels and dimes and there are others that I’m forgetting. It adds up quick.

Definitely better than inventing a way to keep the aw4 and likely much more reliable than a built stroker.
Click to expand...

The donor is a truck so that means I need to change the intake, but the pan should be close. If I get in a pinch I'll use the truck intake and cut a home in an junkyard hood until I can source everything to change the manifold out. I'll make my own mounts so I might be able to get a little more headroom. I've seen one guy claim he got enough room, but I don't really know how.
If I use the jeep pcm and make my own aw4 adapters I can skip the transfer case and other transmission parts.
I'll need to pay for the tach module, but that's not terrible I guess.
For the radiator I was thinking I'd fit up a universal unit. I can weld my own inlet/ outlet if needed. So if should be well below $500.
I was planning on doing my own wiring since I would have the full donor vehicle and that should help.
I can make my own intake, the $200 sounds right.
Anti theft reprogramming is a given.
I figured if I couldn't get the correct accessory brackets from the junk yard, I'd try to make my own. Solidworks is fun and I can use the 45kw laser st work or the cnc mill if needed. My thought was to use the jeep a/c compressor and power steering pump if possible. We'll see.
 
I’m not familiar with the accessory drive setup needed to fit the XJ engine bay, but a lot of GM cars use the smaller TC pump rather than the giant truck P pump. The Colorado/h3/trailblazer/envoy and I think gen 4 trucks use TC pump in the same location as the gen 3 P pump. Just a slightly different accessory bracket.
I converted my LM7 in my swapped Colorado from P to TC.

Intake, cam, and a tune is typically good for 400 at the crank depending on how crazy you get with the cam. I wouldn’t waste my time with head porting at that power level. I’m not sure what the AW4 can handle or what there is for aftermarket. But even at that power level some insurance building of the 4L60 is a good investment. Hence the recommendation for a 4L80 (if your drivetrain length can handle it) or the 6L80 (if your pockets are deep enough).

My next swap will definitely be the 6L80. Lower first gear and double overdrive? Yes please!



Off topic, but… having owned a couple, my biggest gripe with the AX15 is the non synchronized R gear. Can’t comment on what it can handle for power. But my second one ran great with redline MTL for fluid. The VQ40 really intrigues me as a 6 speed manual option. I know of one in an 800hp AWD setup.
 
VAhasnoWAVES said:
I’m not familiar with the accessory drive setup needed to fit the XJ engine bay, but a lot of GM cars use the smaller TC pump rather than the giant truck P pump. The Colorado/h3/trailblazer/envoy and I think gen 4 trucks use TC pump in the same location as the gen 3 P pump. Just a slightly different accessory bracket.
I converted my LM7 in my swapped Colorado from P to TC.

Intake, cam, and a tune is typically good for 400 at the crank depending on how crazy you get with the cam. I wouldn’t waste my time with head porting at that power level. I’m not sure what the AW4 can handle or what there is for aftermarket. But even at that power level some insurance building of the 4L60 is a good investment. Hence the recommendation for a 4L80 (if your drivetrain length can handle it) or the 6L80 (if your pockets are deep enough).

My next swap will definitely be the 6L80. Lower first gear and double overdrive? Yes please!



Off topic, but… having owned a couple, my biggest gripe with the AX15 is the non synchronized R gear. Can’t comment on what it can handle for power. But my second one ran great with redline MTL for fluid. The VQ40 really intrigues me as a 6 speed manual option. I know of one in an 800hp AWD setup.
Click to expand...

The 6l80 would be a cool swap. My wife's gx460 makes me appreciate a 6 speed auto. We had a road trip up to northern Idaho about a month back and the canyons and stuff were a pleasure with the decent power from the 4.6 v8 and the good trans with the automanual deal.

My wife's gx also makes me want to figure out a kdss style sway bar system for the xj and maybe my truck.


Back to the swap ideas... Does anybody know if I can adapt a 242 t case to a 4l60e or 4l80e without the $500-600 Novak adapter? I'm talking like some frankin case stuff like. Taking an h2 full time 242 input and swapping it similar to the chevy 231 frankin case people are using. Or maybe taking an h2 full time 242 and modding with jeep 242 parts so it has a 2hi.

I really like the idea of having a full time or more road worthy 4wd option without being married to actually being full time. I guess I could do manual hubs with a gm full time 242 case. That sounds less than ideal.

I'm leaning more towards using the 4l60e, but we'll see. I looked at the donor truck today. It looked alright. The body wasn't as bad as I expected. I told my buddy I'd take it, so there's that. It's a 1999 Silverado with the 5.3, auto (I'm assuming it's none other than the 4l60e) and 4wd.
 
I'm curious as to why you abandoned the 4.0 stroker you were building?
 
RCP Phx said:
I'm curious as to why you abandoned the 4.0 stroker you were building?
Click to expand...

I didn't abandon it. I built a stroker and now I'm rebuilding it because it ate the thrust bearing. Luckily I caught it before it did anything major. I just needed to tear it completely down to actually see that. As I'm putting it back together I am realizing I don't really love the power to work ratio I've achieved.
 
RCP Phx said:
That's interesting, did you figure it out? What timing set did you use?
https://www.naxja.org/forum/showthread.php?t=1157412
Click to expand...

Russ was thinking I just didn't set the crank right. I couldn't exactly recall what order I set the caps and smacked the crank back and forth. I was thinking I did it fairly close to how he suggested, but I think I may have done about half torque before smacking the crank. Everything else looked fine besides having copper and silver bearing junk floating around. The thrust surface even looked alright after closer inspection. I just need a hone and new cam bearings for good measure. I'm doing a different cam while it's out too. I always planned a bigger cam after a year or so and that's right on schedule I guess.
Timing set was whatever came off the engine when I bought it (maybe melling). The engine was rebuilt a few thousand before I got it and the timing set looked alright. I'll be upgrading it though. This was also planned with my cam upgrade.

What wasn't planned was taking the whole engine out, but that's life. To be honest I was extremely lucky I caught it as soon as I did. I thought it was cam bearings or something because my oil pressure dropped slightly and I heard what sounded like valvetrain noise. Not even sure how what I heard was the thrust, but I don't see anything else besides slightly lower oil pressure maybe causing something to make noise.
 
I think it would be nice if the one's that have put in a LS motor said what parts they used ? Like was it a 5.3 or a 6.0 what trans and transfer case they used . what they did for a radiator and a cooling fan , did they keep the A/C ?
 
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