Because the Suburban body had to be lifted 2 inches to match the height of the front end,
There were other complications. Because the diesel uses by-wire electronic throttle control, the body used must have this equipment installed. It can be retrofitted and comes standard with 8.1L trucks and SUVs. The various body and engine control modules must communicate with each other, and because they came from different trucks, a trip to the GM dealer for programming was necessary when everything was hooked up. Armstrong has learned that sometimes you plug everything in and the trucks run normally. Sometimes, the modules won't talk. This results in limp-mode operation. Either way, Bill takes the precaution of a dealer visit. Diesels also require Hydroboost power brakes, which necessitated another retrofit. Armstrong reckons that a 2500 Sub body would have been more of a bolt-on, and if it were a 2500 with an 8.1L, it would have had Hydroboost and an electronic throttle.
The chassis was then given all the rest of the 2500HD truck's drivetrain, including the 11.5-inch American Axle rear axle and springs. It all bolted up, though Armstrong had to relocate the transfer case mounts--just a simple drilling job. Because everything was '02 vintage, Armstrong was able to find matching colored parts and there was absolutely no painting or bodywork in the conversion, other than building the previously mentioned rear valance.
Bill Armstrong at work on is current project, building a Duramax-powered Crew Cab from par
So how does it drive? Just like it was a factory rig. It's everything GM should offer but doesn't. After driving it, you'll wonder why. It's powerful, fast and can pull a house. What's not to like? The fuel mileage is somewhat better than a pickup, due to improvements in aerodynamics. Bill reports an honest 20 mpg on local rural roads and recently towed a 24-foot trailer cross-country with 16mpg economy. When asked if the Dura-Sub will light up the tires, he just smiled. So what's the bottom line on the conversion? Armstrong says, "I don't know if anything in the conversion was particularly hard, but it did require a lot of research." On hearing that, a person must realize that "easy" to a talented fabricator with lots of experience building trucks from pieces might be a nightmare to the rest of us.
As for bucks, Armstrong reckons he can build diesel Subs for $10,000 to $15,000 less than a new high-end Duramax pickup (which is probably cheaper than the mythical factory Duramax Sub would be; figure about $50K for one), while using new parts that come from damaged-in-shipment vehicles that are sold for salvage by the factory without ever having been registered. As to practicality, on one hand you get something basically new that you can't get anywhere else (yet), and get it cheaper. On the other, you have no warranty and a salvage title. What's next for Bill Armstrong? Local interest in his Dura-Sub has prompted a few people to make orders. He's also converting a few late-model gas pickups to Duramax configuration, but he is also planning to do a Duramax Avalanche and we'll keep you posted about that. Yes, Bill will entertain orders for a Duramax Suburban or Avalanche.
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