H3 More power.

[Ghostbuster]

I have come to the conclusion that I am going to keep my Hummer forever.

The 300 hp from the 5.3l V8 isn’t going to cut it forever.

I would really like to put a LSA engine in it. If you don’t know what an LSA is, it is a GM 6.2L Supercharged V8 engine that they put in Chevy Camaro zL1s and Cadillac CTS Vs dating back to 2009.

The LSA can make anywhere from 556hp to 580hp.

If I go this route I would most likely need a 6L90e transmission, as well as beefing up the rest of the drivetrain.

With a project like this comes many questions.

What do I do with the front Diff and driveshafts? I don’t want a solid axle.

I suspect I’ll have to go full custom with the front Diff. I think Bebe did something like that.



Can the stock transfer case handle that much HP and Torque? I’m guessing it can’t. What would be a good solution? Should I somehow get a selectable transfer case?

Can the rear axle even handle that much power?

What about cooling?

I’d definitely want to get adequate cooling and a dedicated transmission cooler for sure.

Can I run a mechanical fan and E fans with the LSA? Or only Electric fans? Do you think I’ll need to make the fake hood vent thing functional?


I am not going to rush into this project. I want to do it right the first time.

I know there was a guy who put a 6L80 in with an adapter plate, and I know there is some guy out there that can do the wiring harness.


If anyone has any suggestions or advice I would greatly appreciate it!


Threads are worthless without pics.

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[amrg]

Look at my thread and you will find alot of info. Your truck is even the same color as mine plus we both have black wheels!

Do you live in a hot climate?

 

[Ghostbuster]

Look at my thread and you will find alot of info. Your truck is even the same color as mine plus we both have black wheels!

Do you live in a hot climate?

Will do. Arkansas can get pretty hot and humid.



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[amrg]

How about fitting an LSA supercharger on the 5.3? The whole thing wouldnt cost as much since the supercharger can be found cheap along with the fuel rails/tb and you can buy the correct adapter foe it. Power levels are gona be around 450 hp with safe boost levels on a stock bottom end. That power with a 6l90 is more than enough to let you spin 37" tires from stand still all the way to 3rd gear! Just saying...

At almost 600 hp, the H3 isnt physically capable of handling that much power. Even if you figured out the transmission, the tcase may survive and so would the front diff, but the half shafts will really hate it.
Then the suspension, the front control arms will go crazy with all the torque going thru and it will negatively affect steering (you wont go straight). The torsion bars arent strong enough and neither are the rear leafs, the truck will end up pointing in the sky everytime you go 75% throttle! Cooling will also be another major issue.

I run 500 hp, had to do alot of work to address my cooling, same with trans, had to upgrade my rear suspension with stiffer springs and after adding 37s I can now do 75%+ throttle in first without my truck side swerving into the next lane. (With the gearing of a 4l60)

 

[Ghostbuster]

I thought about that.

I might do that, but I would want to pull the motor and upgrade/ replace some internals for long term reliability.

If I did that I would probably just get a built 4L60e and pray the rest of the drivetrain can withstand the extra power.

That would be a lot cheaper.

I’m guessing $7k for the supercharger and all the extra pulleys, fuel rails, injectors etc. Plus install and tune. Maybe less.

Then maybe $2000 on upgrading internals of the motor.


Then probably $3500 for a transmission.



I was planning on going all out $20k+ for LSA, 6L90e, custom front diff, new t case etc. LOL







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[amrg]

Then y dont you do a stroker build instead if you're planning on going into the engine? Thats another idea! Then add a 6l80/90 instead of building up a 4l60e! If I was in the states I wouldve done exactly that but sadly overhere it would be better to get the ready stuff than build them! As for the front diff, remove the drive shaft and go 2wd (or if possible, modify the stock tcase for a 2wd mode like the 100 series LC)

So many options!

 

[atvspeed4]

With a stock 2011 6.0L and 6L90/ factory 4.56 gears we can spin the 37s coming out of a corner in 2wd. I would avoid a supercharger if you can as heat is a major problem under the hood with higher power levels. I'd just do a 6.2L and built 4L65E. If you do not have an adventure model I'd throw a trutrac in the back to help with delivering power.

On our h3 with the front trutrac it's amazing how much it helped with torque steer and one front tire spinning when you floor it and shift.

 

[amrg]

With your setup do you even use 4LO?
I think someone with the regular 2.7:1 tcase would end up with more torque than a stock setup 4:1 case

 

[atvspeed4]

With your setup do you even use 4LO?
I think someone with the regular 2.7:1 tcase would end up with more torque than a stock setup 4:1 case

Yes as the only way to run the 6l90 is using a np241, the gearing is about the same as the factory adventure setup which feels spot on.

 

[amrg]

Do you have any more info on this?

 

[06 H3]

I thought the 6l80 fit but not the 90

 

[atvspeed4]

I thought the 6l80 fit but not the 90

6l80 with custom nightmare tcase adapter $$$ and resplined output shaft will work in stock h3 with stock t-case

6l90 with Np 241 using dodge input shaft and custom bearing adapter will fit stock h3 and clear the torsionbar crossmember after massaging the t-case unused mounting bosses to clear the torsionbar. (The np241 is much shorter than factory transfercase) We also had to design a custom transmission/ transfercase shifter tower, crossmember and wiring to make it work with the computer but as of right now it still requires the encoder motor to be mounted up out of the way on a dummy adapter plate we made. This is what we have in our 2006 Red shop truck with the 6.0L

I dont get all of the excitement of a 2wd transfercase. We have it and there is no noticeable difference in fuel economy. Especially with more than stock power the truck is much more enjoyable to drive with the AWD factory case.

If you were going to keep the truck for a long time I would do a lsx 454 trade the heads for non ls7 style ones and run a truck intake, install griffin radiator and severe duty fan clutch, largest transmission cooler you can find, built 4l70e, tru tracs front and rear, Install the firmest valving you are willing to live with in Fox shocks at all four corners to help with suspension squat then have some fun.

 

[Ghostbuster]

What do y’all think about putting a 6.2L in it? One that hopefully doesn’t have AFM.


I don’t want it to sound like a race car though, you know the low idle big thud thud thud lol.

So a 4L70e upgraded would be better/easier than a 6L80e in the long run?






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[amrg]

It all depends on how much you are willing to spend and where you see the truck going in the future.
Atvspeed4 has a nice build and his recommendation is nice too.
A 6.0 is cheap and easily available with the cast iron block. Its a good start, 400 tq and can be built in the future, you can add a torque cam to push it up abit and thats good with the stock 4.10 gearing and the 4l60. It will still be fun with 37s too.

As to the 2wd thing, my kind of terrain (desert/dune/beach) it is fun to have a 2wd mode. Just turn abit and let it rip

 

[06 H3]

I have a 6.2 it’s significantly better then the 5.3

 

[SlcHummer]

I have a 6.2 it’s significantly better then the 5.3

I do like that my 3.5 gets 15-17mpg with 35's, torsion bar/1" body lift, and PCM tune...but I can't hide my jealousy of a 5.3 or 6.2

 

[atvspeed4]

I do like that my 3.5 gets 15-17mpg with 35's, torsion bar/1" body lift, and PCM tune...but I can't hide my jealousy of a 5.3 or 6.2

My daily driver is a 2006 H3 adventure 5speed manual on 37s no tune and stock gears. I have consistently been getting 15-16.8 mpg per tank which is mostly around town driving.

Our 2006 H3 that has a 6.0L vvt, 6l90, np241, 4.56 gears and 37s gets 12-13 mpg. With 4.10 gears it would improve but we eventually plan on going bigger than 37s so we want to keep the 4.56.

Our next swap is a 6.2L/ 6l80e out of a 2014 camaro ss that we are going to be doing AFM delete and a cam favoring torque over hp thats going into another 2008 adventure we bought. That will most likely be on 37s as well so ill be interested to see what kind of mpg it gets.

 

[Schwarttzy]

If the 5.3 V8 has a good bottom end, this is what I recommend, over 6.0 6.2 and etc.

1. FAST LSXR 102mm intake, has better HP and Torque at all rpms https://www-hotrod-com.cdn.ampproje...ds-tested/amp/?usqp=mq331AQCCAE=&amp_js_v=0.1 https://www.jegs.com/i/FAST/244/146302B/10002/-1?ymm=4294829649+4294827333+4294827228

2. This truck Cam shaft 189-400-13 http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1619&sb=2

3. And Some better flowing heads

Should make one heck of an upgrade

https://www.onallcylinders.com/2018...-for-lh8-engine-mods-to-maximize-performance/

 

[5gn-h3t]

There’s a truck version of that intake. The LSXRT.

 

[amrg]

The fast intake makes more power mainly due to the 102mm tb which is an upgrade over the 90mm ls3 or the 87mm truck tb. But on an H3 the intake setup up the line is restricted at the maf sensor (90mm) and at the fender inlet (?) Which would need to be addressed if you were to make use of the bigger TB opening. As for the intake manifold itself, the oem manifolds flow really really well which is why not many opt to upgrade. The same goes for the exhaust manifolds, shorty style headers dont offer any improvement over oem so if someone was to swap in headers LT are the way to go.

 

[amrg]

My daily driver is a 2006 H3 adventure 5speed manual on 37s no tune and stock gears. I have consistently been getting 15-16.8 mpg per tank which is mostly around town driving.

Our 2006 H3 that has a 6.0L vvt, 6l90, np241, 4.56 gears and 37s gets 12-13 mpg. With 4.10 gears it would improve but we eventually plan on going bigger than 37s so we want to keep the 4.56.

Our next swap is a 6.2L/ 6l80e out of a 2014 camaro ss that we are going to be doing AFM delete and a cam favoring torque over hp thats going into another 2008 adventure we bought. That will most likely be on 37s as well so ill be interested to see what kind of mpg it gets.

I was doing 10.5/12mpg city/highway and i attribute it to the higher stall converter im using (3K). Ever since 37s city mileage dropped to 10mpg and i attribute it mainly due to the fact I cant keep the converter locked at 50 mph (I can program it but I dont want to lug the motor at those low rpms)
On the next swap, are you staying with the stock tcase?

 

[atvspeed4]

Yes we will be running stock tcase. It's more than strong enough and I much prefer the drivability with awd.

 

[Schwarttzy]

There’s a truck version of that intake. The LSXRT.

LOL that's the right one, ran out of time and got called back into work. But circling around for ease of installation I would want to go with the 92mm version.

The improved "LSX™ 92mm Black Intake Manifold" keeps the the low-end torque and should require nothing special to bolt on.

https://www.fuelairspark.com/lsxtm-92mm-black-intake-manifold.html



Also I remember that I found something I think is better than getting new heads.

Katech
24324 Sorrentino Court
Clinton Twp., MI 48035

Katech CNC ports the heads to make improvements on our already great flowing heads

https://www.youtube.com/watch?v=K_9zfcW6P4Q

https://store.katechengines.com/cnc-port-ls2ls6truck-243-799-317-035-cylinder-heads-pair-p589.aspx


Here's the cam they are currently recommending

https://store.katechengines.com/katech-cathedral-cam-kit-p818.aspx

Although, they mention I might want to up the stall speed of the torque converter. Which I'm not a fan of because this is the opposite of what a rock-crawler would want to do.



Overall I would hope to see the 5.3 in the 400# of torque range and only be down for 2.5 weeks and out of pocket around $4,000 all said and done.




By the way... if you guys still have the factory exhaust I really recommend getting the Gibson 612801 absolutely love it. Just don't put the stupid exhuast tip on there for me please.

https://www.jegs.com/i/Gibson/462/612801/10002/-1?ymm=4294829649+4294827333+4294827228