I think there are many H2 (as well as H1) owners that may be considering a Duramax conversion.

There are 2 companies that specialize in that conversion Mash Motors and Predator Motor Sports.

I thought it might be interesting in starting a new thread on those who have gone down this road and can perhaps share their experiences, joys and pitfalls. Also their experiences with the vendors and the process.

 

I'm also interested in this and think I've watched every video and read the entire internet and there isn't much out there. I just bought a one owner 2005 H2 out of Albuquerque and am VERY happy with the condition. The former owner saved every part that was replaced and every service record. Underneath and the engine bay are impeccable.

Anyway, it would be a perfect candidate for a Dmax swap but only if it's not a hack job and well integrated into the factory systems. Mash has some bad reviews and I have yet to contact Predator. I'd like to do this myself as I have the facility and my sons are good fabricators, There just doesn't seem like there is any detailed information out there.

If I'm not comfortable with the DMax, I'm thinking a 408 stroker or bigger using an LSX block.

 

Congratulations on your find, sounds like a very nice unit, New Mexico is a great place to find a rust free Hummer.

As far as Predator is concerned, they are light years ahead of Mash in many area, they can install the later LML or L5P into an 08 or later H2. They also offer differential upgrades and selectable 2/4 wheel drive.
Mash is still trying to figure out the integrations to the newer Canbus used in the 08/09 H2 vehicles and currently only offer LM7 or LMZ upgrades which are dinosaurs compared to the LML and L5P variants.

If I was going to make the switch I would use Predator. I have watched a number of video's and they advertise 100% compatibility with existing systems in the H2. The only downside to them at last check there is almost a 1 year waiting list you have to get on to get the conversion done. They also keep your old engine, trans and transfer case as part of the deal.

Much of the Dmax upgrade comes down to integration with the H2's computer and hardware systems. With that said upgrading a 03-07 H2 is less difficult and a good mechanic with the proper tools can and have done it. There are a number of youtube video's on it.

As far as switching away from the LQ4 your going to experience similar issues especially if you use any engine combination that uses different computer controls. You may still have to use a stand alone engine control module and you back in the same boat, poor integration with existing systems.

Punching out the LQ4, kicking up the compression ratio and a better camshaft would save you from all of that and give you great performance. Add a tune for the upgraded LQ4 and your done. Personally the least labor intensive is to bolt on a turbo or supercharger, most of the time manufactures of these system offer turn key programming. The only downside is the transmission which will also need an upgrade.

When it's all said and done while a LQ4 upgrade will be much better then stock it won't provide the performance, torque or fuel economy the Dmax would, but your investment will be much much less. And unless you have custom car insurance, if anything happens to your H2 the insurance company will give you a dollar ninety five for it. Something to be factored in.

Anyway, Cheers, enjoy your new H2!

 

If I'm going to spend $40k plus from a company like predator, I'd need to talk to owners of previous builds and probably go and see one. The big mystery it seems is the integration of the cooling stack and integration with the body systems. I haven't seen any integration videos on you tube or anywhere else. Can you share links please?

If I build a gas engine, I believe I can do that much easier. I used tune chips for Corvettes, converted to speed density, built stroker engines or rather assembled them and HP Tuners seems soooo much simpler. If I stay Gen III then it's easy. If Gen IV, then some other things need changed like using the old style knock sensor, relocated cam sensor and 58 to 24 tooth reluctor converter unless I build it with a 24 to begin with. I want torque like my BMW X7 M50i has that makes 550 lb/ft of torque from 1800 to 4800. It's flat like a table due to the twin turbos and tuning. In the H2, the only way I know how to get that is a diesel. The next best thing would be a large displacement gas engine from what I know.

Please send those links if you can. If I have to wait a year for a conversion, I'll never do it. My attention span isn't that long and I'll lose interest by then.

 

Just go up on Youtube and type in "H2 Duramax Conversions" there is at least 7 of them covering various different aspects of the projects.

This is one of the reasons I created this thread, hoping those with first hand experiences of actually owning one and having had the conversion done would share their experiences good or bad.

 

I thought you were talking about electrical integration specifically. I emailed DMax and they screen out people that waste their time. They say specifically do not call about integration. They sell stand alone kits only.

 

Here are some thoughts as I have a Predator 2008 Hummer H2.

Questions you want to consider:

• Do you want to chop up your Hummer - Note that any engine upgrade will require extensive modifications to the engine bay including cutting of metal, changes to the drive train all the way back to the rear axle, and changes to electrical systems in the engine bay. Your baby will be changed and you need to be ready for that. You also need to be prepared to ship it off, and wait for a while for all that work to be performed.
• Gas vs. Diesel - The upgrade to a Duramax Diesel is a proven path and utilizes Chevy engines and parts that fit the H2 so that driver controls operate as intended by GM. The best part is that with a diesel upgrade the vehicle is still serviceable by your local dealer. There are several shops that support Diesel conversions and do them all the time, like Predator. From what I have seen, gas engine upgrades are possible, but are in the custom, one-off zone. I don't believe that you can get them easily serviced.
• Do you want to drive a diesel? Moving to diesel has upsides in terms of power and torque, but downsides in terms of soot, fumes at idle, and engine noise. You will also pay a lot more for fill-ups, with a corresponding increase in MPG. I can tell you my wife does not love the noise of the diesel Hummer, while my son loves it!
• Do you need the power? To handle the extra power requires upgrades to the drivetrain, and requires suspension changes to accommodate the added engine weight.
• Can you get the additional power you need by modifying the engine you have? Consider adding a supercharger (which will also require transmission upgrades to handle the power), or having a chevy custom tuner customize your engine. Ligenfelter (LPE) offered an upgrade for the Hummer H2 which is probably in the ballpark of the diesel upgrade cost. Here is a summary from Motortrend... LPE has boosted the output of the H2's V-8 by 185 horsepower. The tuner removes the stock V-8, blueprints the 6.0-liter's bottom end, and installs forged pistons and a custom roller camshaft. Atop the short block sit a pair of ported cylinder heads fitted with stainless-steel valves, beefier valve springs, and titanium retainers. A Magnacharger air-to-water intercooled Roots-type supercharger and ported intake manifold perch on the heads, cramming 7 psi of boost inward. Oversize injectors funnel fuel as prompted by a reprogrammed factory electronic control unit. A B&B Tri-Flow mandrel-bent, stainless-steel exhaust system quickly vents the spent exhaust and delivers just the right amount of growl while cruising. The final key to LPE's power combo is the addition of a custom torque converter that allows the force-fed engine to efficiently get into its powerband when leaving a stoplight. LPE conservatively rates its dyno-tested package at a square 500 horsepower.
• Are you near your Installer - You really want an installer that will stand behind their work, as you are effectively driving a custom vehicle and will need support. If you need their support, they need to be close enough to support you, or you will need to plan on shipping the car to them.
• Will you get the investment back if you need to sell? Given the investment, you have to pick the right vehicle. I believe that the duramax upgrade makes investment sense for low mileage 2008/2009 Hummer H2s that are already highly valued in the market. Adding a Duramax to a vehicle that is already highly valued, and is in great condition and has many miles ahead makes sense. This is disconnected to when you would actually want to upgrade your Hummer H2 -- which would be after 175K-250K miles when the standard engine and transmission could be reaching end of life. For high mileage vehicles, you may not be able to get your investment back if you have to sell. Additionally, many of the parts that wear on the Hummer H2s are becoming difficult to find and in many cases cannot be serviced. Most of the interior can only be found on eBay or from parts Hummers that have been wrecked. So investing in a vehicle that is under 60-75K would probably be the sweet spot - paint and interior looks new, has not been abused, and has limited wear on the parts that are not serviceable.

In general, the Predator upgrade is very nicely done and the engine performs very well. It looks OEM, can be serviced by any GM dealer that supports GM diesel trucks (e.g., 2500HD, 3500HD). Every GM guy that has looked at it is amazed at what the Predator team did, and they love it.

 

Brunob00

Thanks so much for sharing that with the forum. I must say many on this forum are looking at a number of different upgrades. 2 in particular that are always mentioned is the Duramax upgrade and the Magnason suprecharger.
Both are not cheap and many question and are concerned about shipping their H2's away for extended period of times waiting for upgrades.

Its interesting you mentioned Ligenfelter, they are known for their top notch work. Predator has a good reputation but no one here has shared their experienced. Your the first.

You mentioned you had a 2008, which Duramax did you use. The L5P and the LML are very quiet for diesel. Is that what you went with? Perhaps you can share the complete experience you had including any problems after having it for a while.

I think like you mentioned support is an issue. Predator is California which makes it difficult to just drop in with a problem if you have one but like you said for the most part standard issues can be resolved at a local GM dealer. About the only rub there
would be if there is a specific part they use that's non-standard.

No doubt we are all very interested in what you have experienced. Thanks again!

 

Thank you also for that write up. I just put a deposit down with Mash Motors on a conversion that is scheduled to start Oct/November. He has a 68,000 mile complete take out LMM that he converts an LBZ so it can communicate with a class II bus. Mechanically I'm very capable but I'm not wanting to tackle this swap myself and figure things out. There is not enough resources online to help with electrical integration and cooling stack mods. If I problem comes up after the conversion, I will be able to fix it myself rather than send it back to Mash. I talked to a few of his references and one had zero issues and one had a transmission issue and a cooling issue where Mash took care of it.

I was going to build a big displacement gas engine but I always wanted a diesel. I don't want alot of noise or smoke so my plan right now is to keep it stock.

 

[quote=H2-SUT;402397]I think there are many H2 (as well as H1) owners that may be considering a Duramax conversion.

There are 2 companies that specialize in that conversion Mash Motors and Predator Motor Sports.

3:
https://www.facebook.com/marketplace/item/838249514652241/?mibextid=dXMIcH



​​​​