Forget about the Hummer H1 Alpha with the 6.6L Duramax. The cheapest version costs more than $129,000, and that's not including tax, title, and options. Why shell out more than you'd pay for a new Porsche 911 Turbo when you could buy a used Hummer H1 and take it to Sin City Motorworks for one of their 6.5L upgrade kits? The shop's High Performance packages can bring the non-Duramax Hummers to life with up to 320 hp and 510 lb-ft of torque. Here's how they do it.
 To get access to the turbocharger,...  To get access to the turbocharger, Sin City's Scott "Jaz" Jasmer had to remove the doghouse, which is the giant drivetrain cover inside the Hummer that makes riding shotgun in an H1 so much fun. One look at the madness under the doghouse confirmed we had made the right decision by having a professional shop perform the installation. |  With the doghouse out of the...  With the doghouse out of the way, the next step was to remove the troublesome stock GM vacuum-operated and computer-controlled wastegate controller from the turbo. |  The OEM unit was replaced...  The OEM unit was replaced with this spring-actuated mechanical wastegate controller. |
 Now that the turbo was under...  Now that the turbo was under control, it was time to add Sin City's high-output computer. This unit features unique fuel delivery and start-of-injection timing curves designed for maximum power and torque within the GM-specified exhaust gas temperature limit. |  Sin City says its injectors...  Sin City says its injectors (left) are good for about 40 more horsepower than the stock squirters. They include return tubes, copper seals, and return oil tube gaskets. |  A 3 1/2-inch turbo downpipe...  A 3 1/2-inch turbo downpipe was installed to replace the skinny factory tube. |
 The stock muffler was removed,...  The stock muffler was removed, and it's not hard to picture the restrictions caused by exhaust gasses having to make a 90-degree turn to escape the unit. |  The new high-performance exhaust...  The new high-performance exhaust uses mandrel bends to prevent the turbulence caused by sharp turns in the tubing like those in the stock exhaust. The Magnaflow muffler also greatly improves the exhaust tone of the 6.5L. |  The Sin City crew attached...  The Sin City crew attached a tailpipe to route the exhaust away from the rear tires. The chrome tip is a nice addition to the overall look of our upgraded H1. |
 The doghouse drivetrain cover...  The doghouse drivetrain cover was replaced once the crew was done with the engine modifications. |  Sin City offers an optional...  Sin City offers an optional intercooler and aluminum radiator upgrade to reach the 320 hp, 510 lb-ft torque numbers mentioned earlier. We chose to abstain from the IC/radiator upgrades which include a required 2-inch body lift. |  The Sin City workshop includes...  The Sin City workshop includes tons of professional equipment, including this CNC milling machine that allows the crew to carve complex parts from solid aluminum. |
 One of the CNC products Sin...  One of the CNC products Sin City produces in its shop is billet aluminum taillight bezels for the Hummer H1. You can get them in polished aluminum or powdercoated, like the one we had installed. |  We also had Sin City install...  We also had Sin City install one of their rear running light kits. It's made of two pieces of billet aluminum with a LED strip light to replace the factory panel with three trailer lights. |  Without the radiator upgrade,...  Without the radiator upgrade, we had trouble with the engine wanting to overheat during the warm drive back from Las Vegas. We'd suggest not mounting large off-road lights like these in front of your grille to avoid similar problems while enjoying your H1's new diesel power. |