08 5.3L SWB Considering LS3 Swap, Questions

isaacmaple08

Original poster
Member
Mar 28, 2012
36
Fort Wayne,IN & Tyler,TX
Hey Everyone, Been a few years since I've been by. I just bought a 2008 SWB 5.3L. Coming from a Jeep Grand Cherokee with a 5.7 Hemi and My Charger with the 6.4L I wanted something a bit faster (Yeah should have probably just saved and got an SS, but I wanted a project)

I was considering two possible paths, let me know your thoughts. Based on a few hours of searching I think full bolt on's with the 5.3L i'd be looking at about 400-420HP at the crank meaning Custom Tune, Intake, Transmission Cooler, Thermostat, LT Headers, Cat-back, Underdrive Pulley, Cam, & EFan. I'm guessing about $4500 or so?

Or for similar cost and performance I could get an LS3 from a salvage yard for around $4500-5000 and have the option to upgrade later should I get the bug again. From what i've been able to gather on these forums being a 2007+ I would need to swap ECM's right? Or would I just need a tune?
 
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Sparky

Member
Dec 4, 2011
12,927
What you have going for you is they are both part of the LS family, so that helps.

I really don't know on the computer though. I want to say that the computer could stay and just get tuned for what you're doing, but I don't know if some of the sensors and stuff use different signalling.

Is your truck 4WD or is it RWD? The 4WD system would make it more complicated. Either way you go, doing an oil pickup relocation kit so it pulls from the rear instead of the front of the pan would be highly recommended if you're doing all this.
 

isaacmaple08

Original poster
Member
Mar 28, 2012
36
Fort Wayne,IN & Tyler,TX
Gotcha, well that's good news, it seems fairly hook up and go as far as physically swapping, just wondering about Harness/ECU. It is 4WD, what kinda complications am I looking at for that?

I read that the LS1 on the SS highly recommended the pickup relocation due to it being up front and starving it for oil on Acceleration, is that the gist of it?

Thanks for the quick help!
 

Sparky

Member
Dec 4, 2011
12,927
Basically yes. The 4WD has the intermediate shaft through the oil pan, so the starvation issue on heavy acceleration is even worse as there is even less oil up front.

It is just more stuff to deal with on the 4x4 system that you'll have to be mindful of. The funny oil pan, the disconnect, the differential, driveshaft, transfer case... If you get too much power you'll need to beef up the transmission, and then I don't know what the limits are of the transfer case. Probably just don't go too crazy with the throttle while in 4x4 as you don't want to bust up the rather small front differential. The rear 8.6" is fairly strong so you'd probably be OK with it, or you could upgrade to the bigger SS rear axle if it did break.
 

Bill Reid

Member
Dec 18, 2015
83
Chandler, AZ
Isaac,
Few things off the top of my head :biggrin:

1) I recommend getting a hold of a tuner near you because either way you go (ECM w/ LS3 or use existing) you will need some sort of tune to get whatever engine set up you decide on running/shifting properly. With an LS3 motor you will have to tune out the ECM looking for/managing AFM/DOD. Like Sparky says I don't know is if all of the LS3 sensors are compatible with your current ECM. I know the older GenIII stuff was 12 volt based. I believe the switch to 5 volt came with the advent of the 58x reluctor wheel based engines. Your existing 08 5.3 should have a 58x reluctor wheel on the crank. So, your existing ECM should be compatible. Hopefully the cam sprocket / sensor pickup are the same as LS3. I recommend the purchase of HP Tuners or whatever your tuner prefers. Then you can datalog and send logs/tunes back and forth by email if necessary. If your tuner is close enough to tune the truck directly then all the better. Either way - someone will need to have tuning software for a V8 based trailblazer.
2) The LS3 has rectangular port cylinder heads. Yes, a better head. But you would have to use the LS3 intake or find a later model truck intake to work. Sticking with LS3 intake would require you to fabricate a CAI... as I don't know of anybody who makes an off the shelf solution for the low profile intake manifolds. Not a big deal just the little stuff can start adding up quick...
3) The LS3 is a 6.2L right? With more cubes comes more fuel needs. That will probably need to be taken into consideration whatever path you take as I do not know what the 5.3 based trucks in-tank pumps capabilities are... yet :biggrin:
4) With more cubes comes the potential need to upgrade the entire exhaust system in order to capitalize on the power delivery of an LS3... or an upgraded 5.3. You mentioned adding headers and a cat-back for the 5.3 scenario... you might need to do the same on an LS3 setup. Sure the factory 5.3 exhaust will work... and should work well enough assuming the condition of the original catalytic converters are up to the task.
5) I agree with Sparky that the rear 8.6" diff is probably stout enough to take an occasional beating. A 14 bolt SS rear diff will require an SS AWD rear drive shaft to accompany it. I am assuming here the location of the of the 4WD rear driveshaft exit from the transfer case is the same location (length wise) on an AWD setup. Otherwise its more money for a custom driveshaft. Oh, chances are the 14 bolt diff gear ratio will not match your front diff. More money... more money.
6) Depending on the miles of the current trans you might consider, at least, a shift kit along with tuning of the shift points/firmness. Corvette servo's, upgrades to accumulator pistons, and perhaps a thorough check of the valve body by a reputable trans shop for piston/bore checks along with solenoid checks are money well spent.

Myself I just bought an 06 short wheel base 4X4 Trailblazer. Already considering deleting AFM/DOD... as in cam/lifter swap. I do have a set of very low milage LS6 heads/cam out of an 03 Z06 that would be a good foundation for a swap. I have thought about a cat-back. Another thing I'm considering is ditching the electro-viscous fan clutch in favor of electric fans. It all adds up though. For now, I'm just fixing all the little stuff that broke and the previous owner did not bother to fix...
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Another thing about the trans., the 4L60E will not be able to hold up behind that engine so either a built up replacement or an upgrade will be required (4L70E or 4L80E).

Then, there is the transfer case. I don't know if this particular TC was used in anything close to this engine combo to know if it can handle the torque. The AWD system from anything but the SS' Torsen full time AWD sucks (like in the 9-7x, Rainier, Bravada). It's like having it in A4WD on your current TC. Basically part time AWD and torque capability would be limited IMHO. If it were me, I'd turn it into a 2WD street bruising sleeper. Less things to worry about.

A CAI might not be necessary if you can use 4" silicone turbo tubes to the existing air box. I've done this and you should be able to clear the fan if you keep the stock fan (being an '08, you already have the thermal clutch). It would just be lower with the car intake manifold.

Speaking of fans, unless you get a custom made rad, I'd stay away from e-fans. The existing rad is marginal and is over compensated with the stock mechanical clutch fan. As far as I can tell, the SS rad is the same as in the 5.3 trucks so no help there.
 
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isaacmaple08

Original poster
Member
Mar 28, 2012
36
Fort Wayne,IN & Tyler,TX
Thanks everyone, great info. I'm in touch with a guy in Cleveland and am looking to do the swap about 6 weeks from now depending on delivery and whether or not it's snowing yet. If it is it'll probably be later since I don't really wanna drive the Charger in the snow.

Another thing about the trans., the 4L60E will not be able to hold up behind that engine so either a built up replacement or an upgrade will be required (4L70E or 4L80E).

Then, there is the transfer case. I don't know if this particular TC was used in anything close to this engine combo to know if it can handle the torque.

Speaking of fans, unless you get a custom made rad, I'd stay away from e-fans. The existing rad is marginal and is over compensated with the stock mechanical clutch fan. As far as I can tell, the SS rad is the same as in the 5.3 trucks so no help there.

So i'm looking at the possibility of switching to a 6L80E. The builder I went with said the following "I've not done the swap to an 80 but I've read up on it because I plan to do it to an Fbody here shortly. It's not all that tough in a Fbody and I'm sure the worst part may be mating it to your transfer case but even that shouldn't be bad. I'll read up on it to see if there is any issues."

I've found a ton of lightly used (10-23K) ones for like the $750-$850 range, which is bonkers coming from Mopar where everything is crazy expensive lol. so add about $925 for the Conversion kit and I should be good there.

Isaac,
Few things off the top of my head :biggrin:

1) I recommend getting a hold of a tuner near you because either way you go (ECM w/ LS3 or use existing) you will need some sort of tune to get whatever engine set up you decide on running/shifting properly. With an LS3 motor you will have to tune out the ECM looking for/managing AFM/DOD. Like Sparky says I don't know is if all of the LS3 sensors are compatible with your current ECM. I know the older GenIII stuff was 12 volt based. I believe the switch to 5 volt came with the advent of the 58x reluctor wheel based engines. Your existing 08 5.3 should have a 58x reluctor wheel on the crank. So, your existing ECM should be compatible.

Right on, yeah I think the guy that is doing the swap is a HPTuners shop and I'm looking at getting a dyno Tune after installation. So I guess my Diablosport Trinity will be worthless for this lol

2) The LS3 has rectangular port cylinder heads. Yes, a better head. But you would have to use the LS3 intake or find a later model truck intake to work. Sticking with LS3 intake would require you to fabricate a CAI... as I don't know of anybody who makes an off the shelf solution for the low profile intake manifolds. Not a big deal just the little stuff can start adding up quick...
3) The LS3 is a 6.2L right? With more cubes comes more fuel needs. That will probably need to be taken into consideration whatever path you take as I do not know what the 5.3 based trucks in-tank pumps capabilities are... yet :biggrin:
4) With more cubes comes the potential need to upgrade the entire exhaust system in order to capitalize on the power delivery of an LS3... or an upgraded 5.3. You mentioned adding headers and a cat-back for the 5.3 scenario... you might need to do the same on an LS3 setup. Sure the factory 5.3 exhaust will work... and should work well enough assuming the condition of the original catalytic converters are up to the task.
5) I agree with Sparky that the rear 8.6" diff is probably stout enough to take an occasional beating. A 14 bolt SS rear diff will require an SS AWD rear drive shaft to accompany it. I am assuming here the location of the of the 4WD rear driveshaft exit from the transfer case is the same location (length wise) on an AWD setup. Otherwise its more money for a custom driveshaft. Oh, chances are the 14 bolt diff gear ratio will not match your front diff. More money... more money.
6) Depending on the miles of the current trans you might consider, at least, a shift kit along with tuning of the shift points/firmness. Corvette servo's, upgrades to accumulator pistons, and perhaps a thorough check of the valve body by a reputable trans shop for piston/bore checks along with solenoid checks are money well spent.

Myself I just bought an 06 short wheel base 4X4 Trailblazer. Already considering deleting AFM/DOD... as in cam/lifter swap. I do have a set of very low milage LS6 heads/cam out of an 03 Z06 that would be a good foundation for a swap. I have thought about a cat-back. Another thing I'm considering is ditching the electro-viscous fan clutch in favor of electric fans. It all adds up though. For now, I'm just fixing all the little stuff that broke and the previous owner did not bother to fix...

Right on, yessir I looking at going with the 4" PCM of NC intake, it should be the same as on SS with the LS2 right? or is the TB in a different location?

I was going to go with headers anyway to eliminate the restrictive manifolds, perhaps not exhaust or keep it as quiet as possible, I'm kinda wanting it to just look and sound (as much as possible) as a standard TB I6 :wink: now that i'm doing the swap.

I'm basing my thought that the transfer case can take the power (if I flipped over to 4 high) on a few threads but this in particular, let me know if this is bad info though - http://forums.trailvoy.com/showthread.php?t=15725 otherwise as you said hopefully the diff's will hold so long as I don't throw slicks or really meaty tires on the truck.

I'm also with you on the fixing stuff haha! I bought this thing and didn't realize all the speakers were blown except for the front tweeters. should be getting some new Speakers and nav unit tomorrow for this weekend's project as well as taking the driver door control board to see if I can fix the electronic door lock switch on that side.

I suppose it would be an entirely different thread for this question, but if I wanted to add some factory options like Foglights or Steering wheel controls or power seat is that doable? Or mor e trouble than it's worth?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Whatever happens, we would love a write up!
 
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Bill Reid

Member
Dec 18, 2015
83
Chandler, AZ
I suppose it would be an entirely different thread for this question, but if I wanted to add some factory options like Foglights or Steering wheel controls or power seat is that doable? Or mor e trouble than it's worth?

I believe some have added foglight wiring using a foglight equipped light switch module and aftermarket relay/wiring. I found a front (foglight equipped) wiring harness at the junkyard in good shape and swapped it in my 03 TB. I then had to reprogram the PCM (with TIS2000 and a Tech2) with the option for foglights. It works... now I just need to find a foglight bumper or cut up the one I have and fabricate some brackets. My VIN had the option to add foglights. I am not sure all TB's (w/o fogs) had this reprogrammable capability. So, you can see factory wiring can be added in to work... but its a process and you have to have access to a Tech2 and a Laptop equipped with TIS2000. I did a writeup on it in the Tech2 section.

I added steering wheel controls and a DIC equipped cluster on my 03 as well. I also swapped in an 03-05 full size truck 6disc factory headunit. The headunit was tricky to program (through the BCM) but I got it to work. The stereo controls do not work on the steering wheel but the buttons for the DIC do work. I might be missing a wire or 2 that I will someday troubleshoot.

Power seats can be added too... been there done that :smile: Again, I went to the junkyard and found uncut donor wiring to support it, pulled the seats and carpet out to open up the interior harness to add the wiring in. My 03 TB did not have originally have wiring to support power seats but I have seen TB's in the junkyard where the harness had the wiring in place all the way to the connectors under the seat but had manual seats. Maybe what I saw at the junkyard came that way from the factory or maybe it didn't. Again, its a process of figuring out what wiring you have under the seat(s) and determine if you need to add anything after researching schematics. For the seats I just removed the manual hardware and swapped in the power seat hardware. If you are thinking heat/memory option then you are talking about reprogramming the BCM (possibly with a VIN equipped with the option)... as heat - think safety here- is managed through the BCM.

Bottom line is these 3 options can be a LOT of work but they should be possible for you. You definitely become one with TB wiring :smile:
 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
His is a 2008, which I think are beyond the Tis2000 programming capabilities.
 

isaacmaple08

Original poster
Member
Mar 28, 2012
36
Fort Wayne,IN & Tyler,TX
Just following up with you guys on the last part for adding a few factory options, working on transplanting in some SS seats and Tach next week, I came into a clockspring and steering wheel Controls for cheap so I wanted to know if anyone had an updated writeup on the DIC Upgrade?

I looked here where an old article used to exist but sadly its gone. http://forums.trailvoy.com/articles.php?do=viewarticle&artid=113
masanca

Thanks everyone
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
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