H3 New Engine Swap!!

[06 H3]

If I recall correctly, F5 indicated that GM made changes in for the 2008+ models to the firewall and/or tunnel to accommodate the 5.3 so some sheetmetal work may be required.

Good point I remember him saying that now that u brought it up

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[SC_Hummer_Guy]

Where as around here it can get country quick and we like the off chance of running in the mud. My ultimate goal for the truck to take some back trails here, or run in Moab which are totally different conditions, or even RC which are still different then down here. Either way it's beginning to seem the alpha swap is gonna be the best all around idea. And have a custom low gearing set up put in so I can crawl when needed, but still have the ability to run through some mud if I like!

And if it comes down to doing some sheet work, then @$&!# but whatever it takes I guess.


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[SC_Hummer_Guy]

I just thought of this too! If there is gonna be sheet work done to where ever on the truck, is that gonna affect me getting some UCP's, or dual battery set up's, or any other non sense i decided to put on my truck? As in will it have to be custom made?


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[MaxPF]

If I were spending the money to do a V8 swap into a later 3, I wouldn't do anything other than an L76 or L92 backed by a 6L80E or 6L90E. The 6.0L L76 will get better highway economy since it has Active Fuel Management (shuts down 4 cylinders during cruise), but the 6.2L L92 makes 36 more HP and 40lb-ft more torque. The L92 is the motor they put in the last of the H2's, but I'd probably go with the L76 since fuel ain't exactly cheap and they do get substantially better fuel economy.

I don't remember when 3's were first made, but in general somewhere around 05-06 is most GM vehicles there was a migration to newer electronics using GMLAN for communications between most modules. Also, the PCM, which controls both engine and trans, gave way to separate ECM and TCM. So, in reality, the year of your 3 will determine the easiest powertrain swap candidates. Some may flat-out not work without losing a lot of the toys that you guys seem to like, and that I would probably pull the fuse on (ESC, ABS, TC)

 

[MaxPF]

If I recall correctly, F5 indicated that GM made changes in for the 2008+ models to the firewall and/or tunnel to accommodate the 5.3 so some sheetmetal work may be required.

Just wait till we swap that rear-gear-train Cummins ISB4.5 into your rig. Talk about firewall and tunnell mods :hack::grind::weld::horns:

 

[4speedfunk]

With the H3, things are so "electronified"...it might actually be easier to swap the body over to a 2500HD Silverado chassis. That would give you the Duramax-D, Allison-T, part-time 2WD case, beefier front IFS, and massive rear axle....all pre-engineered. This sounds pretty cool and way easier than building a drivetrain from scratch (like Bully-Dog did). You would have to chop the 2500 frame and shorten it but, thats not too tough. You could probably score a late-model salvage HD for $10K-$14K.

Also, at one time Trailbreaker and I brainstormed making a complete "stand-alone" wiring harness for the H3. It was basically taking a generic "dumb" harness from Painless Wiring, and modding it to fit the H3. It would back-date the H3 to old-school wiring with all the normal electric functions (windows, lights, wipers, etc.). It would have a REAL fuse box with extra accessory ports, (blunts?...really?) a starter circuit, etc. just like all cars used to have...but the drivetrain would be completely separate, and not part of the main harness. This would allow you to run whatever engine management box you needed for your particular motor...without having it tied to the rest of the truck. You could run a carburated small-block, maybe an 80s TPI small-block, whatever you wanted....without dealing with the stock computer. You could also run whatever tranny/t-case combo you wanted to...like maybe a TH-400 with an Atlas? Naturally...this means running a "shell" of a vehicle, and creature comforts would have to go. I'm picturing something more like a NASCAR interior...push-button start...roll cage...headers...AutoMeter guages...etc., so it probably wouldn't appeal to most folks.

Trailbreaker was working with a Delco electrical guy on this when he sold his T, and I assume he lost interest, and scrapped the project.

 

[Mr_Rich]

If I were spending the money to do a V8 swap into a later 3, I wouldn't do anything other than an L76 or L92 backed by a 6L80E or 6L90E. The 6.0L L76 will get better highway economy since it has Active Fuel Management (shuts down 4 cylinders during cruise), but the 6.2L L92 makes 36 more HP and 40lb-ft more torque. The L92 is the motor they put in the last of the H2's, but I'd probably go with the L76 since fuel ain't exactly cheap and they do get substantially better fuel economy.

I don't remember when 3's were first made, but in general somewhere around 05-06 is most GM vehicles there was a migration to newer electronics using GMLAN for communications between most modules. Also, the PCM, which controls both engine and trans, gave way to separate ECM and TCM. So, in reality, the year of your 3 will determine the easiest powertrain swap candidates. Some may flat-out not work without losing a lot of the toys that you guys seem to like, and that I would probably pull the fuse on (ESC, ABS, TC)

You may not have thought this through when you posted this. I remember reading that the reason Active Fuel Management wasn't used on H3's is because the freakin' thing is a brick and the system wouldn't turn on enough to make the savings worthwhile. It's one thing that GM did that made sense to me. I can't really complain about the economy of my truck, but I can't really brag about it either. I like my 3T for the maneuverability and comfort over my Chevy full-size pickup.

 

[Mr_Rich]

With the H3, things are so "electronified"...it might actually be easier to swap the body over to a 2500HD Silverado chassis. That would give you the Duramax-D, Allison-T, part-time 2WD case, beefier front IFS, and massive rear axle....all pre-engineered. This sounds pretty cool and way easier than building a drivetrain from scratch (like Bully-Dog did). You would have to chop the 2500 frame and shorten it but, thats not too tough. You could probably score a late-model salvage HD for $10K-$14K.

H3/H3T's are a nightmare of electronics compared to earlier pickups. That fusebox is unreal. I think all those circuits support the gov't-mandated systems that I could personally be happy to live without. I really enjoy my H3T, but I still keep my '89 Chevy EC because a lot of the maintenance is so straight forward compared to the newer vehicles.

 

[MaxPF]

You may not have thought this through when you posted this. I remember reading that the reason Active Fuel Management wasn't used on H3's is because the freakin' thing is a brick and the system wouldn't turn on enough to make the savings worthwhile.

That is with the weenie 5.3. I think the 6.0 with VVT and AFM would have enough grunt on 4 cylinders to push the 3 down the highway at 70MPH. They put them in burbs, Avalanches, Silverados, Sierras, and Yukon XL's. If they work on those pigs, they should work on an H3.

 

[rebell_h3]

I googled the conversion of a guy that had a i5 an an put an LS2 in. I believed he lived around Kansas he had alot of good to say about the conversion

 

[mudbug]

I would like to see the new Ford ecoboost engine in a H3.

Hey 4speed you have given me something to think about w/body swap.