The obvious choice is a Duramax or Cummins 6L monster of some type, but has anyone considered something more moderate? I lean towards keeping the stock figures for power and torque for my '06 ( 325hp / 365 lb-ft) as I think the Hummer H2 drives fine as it is. I don't care to make it faster or more powerful as for me it's a comfortable daily driver/go anywhere road-tripper. The real reason for the conversion is to improve mileage, the diesel reliability, diesel range, and sound.
Suitable options:

1. Cummins 2.9L crate engine (191hp / 310 lb ft). Could maybe be beefed up with bigger turbo?
2. Banks 630T 3.0L V6 diesel (221-268 hp / 369-421 lb-ft)
3. I think the Cummins 4BT is too low power and too old a design (would it even fit?)
4. International 4.5L Powerstroke (200hp / 440 lb-ft). I just found out about this cool motor. You can find them fairly cheap as they were used in box trucks '06-'09.

I think keeping the power and torque similar you evade having to change out more parts such as the diff like other people have talked about in the big power conversions. What do you guys think?

 

I think most any of those will be a monster of a project. Even the Duramax conversion is a monster of a project that even doing it yourself generally will end up costing 10K and paying one of the few shops (that advertise it) to do it will run 25K plus. On any other combination you have a massive amount of additional issues like the electrical system (a working instrument cluster is generally desirable), AWD/4WD system, transmission, driveshafts, controls for each of those, 100% custom mounting brackets, modifications and or replacement of the front diff and transfer case if you want to eliminate the full time AWD, etc. Also each of those are such much lower power options that while they might be reliable, pushing around a 6500lb vehicle and the fact that diesel costs more per gallon, on top of the enormous costs you would incur in the custom work to make it actually work properly, that I seriously I doubt would be any more economical. Especially once you consider the tens of thousands you will ultimately spend on engineering everything to have a reasonably functional ride. Even if you did manage to increase it to 30MPG, how many years of driving would it take to recover the costs of the conversion plus the higher fuel costs by the logic of the increased economy?

I think those who have done the Duramax conversion (which would be sweet) really did not go into it based on the idea of better fuel economy. I think its more about increased durability, massively increased torque and horsepower, much stronger transmission. In the bigger picture, the cost of the conversion will likely not be recovered by the improved economy alone before the new engine needs replacing again. The improved economy after the fact is just a bonus.

 

What I'm looking into right now is the Powerstroke 4.5L being the best candidate. You can get them super-cheap as it's not very known ($400) and it's the little brother to the 6.0 powerstroke being that it's the same exact engine with 2 less cylinders. You can also get a 5R11W tranny for relatively cheap as well. I think what would get you are the shop costs but I see youtube videos of guys doing budget swaps without doing ALL the extra stuff you see people doing in the full conversion. I think what would get me most in this is the transfer case as the Hummer is just better and designed around AWD. It just seems to me that you can get away with decent starter swap for a relatively low cost, at least not the $20k+ people throw around. Whether it will pay itself off in fuel savings is just a question of how much you will drive it and how long.

 

IMHO You will ruin the resale value of your H2 if you swap in a 4.5l powerstroke. No one want's a V6 Hummer no matter how powerful the diesel is.

 

That may be, but that's the same thing people said about putting a v6 in the raptor. Another thing is I plan on keeping this truck long term so resale is not really something I need to consider.

 

Plus - who puts a Ford engine in a GM???? Everyone puts GM LS engines in Fords and everything else. GM LS engines are swapped into pretty much everything but how often do you hear about Ford engines being swapped into much of anything (in comparison to LS swaps)? Now Ford 9 inch rear ends and Mustang II front suspension setups - yeah those get transplanted into everything.

Just having some fun..... don't get too serious or bent on my above comments...

I'd have to agree with Phil though. Just does not seem like a worthwhile swap. The electrical and wiring aspect of it.... yikes. You have a LOT of computers in the H2. DDM, PDM, TCM, ECM, BCM, suspension (if air ride), cluster, stereo, HVAC, Onstar, air bag systems, etc. You are going to want to keep all of that working (instrument cluster is particularly useful), while trying to integrate a Ford engine with its required computers and wiring into a GM vehicle. I personally just dont see it being in any way a viable idea due to the drastic differences in how things are controlled and communicate. Making the two different brand systems talk to each other in any sort of reasonable manner just makes my head hurt even thinking about the total clusterf*** of a nightmare that will be to get it all to work together in any sort of a reasonable way. Then you also have the rest of the drivetrain. Figure out some sort of custom bellhousing to connect the Ford engine to the GM transmission? Swap a Ford transmission in? In the latter than adapt that to the transfer case / 4wd / awd system? Gut the 4wd/awd system? Just thinking out loud but if you think a Duramax swap sounds or seems expensive, what you are considering (if you want it truly integrated and nice in any way), will be astronomically more expensive. Duramax, at least you are dealing with computers that are all already wired similar and all already programmed to talk to each other in other applications. Short of the mounting brackets, cooling system stuff, that need to be custom made for the Duramax to sit in the H2 most of the stuff already exists.

 

That makes sense. I hadn't thought of the wiring yet too much. How about these Cummins you see get put in everything? Are they just simple and have tons of aftermarket parts?

 

With multitude of computers and wiring in a modern vehicle the only ones that will be even reasonably easy would be another GM engine that is used in GM trucks.

Don't get me wrong. With enough effort and money anything is possible. Its just that it might end up being easier to ditch essentially most of the factory computer and control systems and change most everything to aftermarket and/or analog controls like all new Dakota Digital gauges in a custom made cluster, etc. But could probably retain the BCM, window, door lock, lighting, etc controls. Either way you are getting into high 5 figure custom work territories. Unless you are a master fabricator and engineer and have plenty of time of course. Many have done the Duramax swaps themselves but not a ton.

 

Putting a supercharger on your h2 will be cheaper, easier, and normally after people put superchargers on their h2’s they usually get a 2-4 mpg increase.

 

I agree but that also tends to make the fun pedal even more fun negating the gains...