Budget Duramax Twin Turbo Setup
In our “The Truth about Twin Turbos,” (July ’10) article, we showed you what it took to design, fabricate, and bolt on a race-proven compound-turbo setup to an LB7 Duramax. That kit replaced both turbos with ball-bearing units from Garrett, featured a wastegate between the two stages of turbocharging, and was powerful enough to win our Diesel Power Challenge. Of course, all that performance and durability came at a price: almost $14,000 at the time. Since then, more compound-turbo Duramax kits have entered the market, and the cost of adding a second turbo to your ’01 to ’04 Chevrolet Silverado or GMC Sierra truck has come down.
| budget Duramax Twins 2003 Chevy Silverado
One of the lowest-cost options for those looking to add more air to their 6.6L Duramax engine is Underground Diesel’s compound-turbo kit, which starts at $2,850. We went to Underground Diesel’s new shop in Las Vegas to see what its $3,100 turbo kit (that’s the cost of the base kit, plus a new battery box and fuel filter) and 12 hours of labor can do to an ’03 Chevy Silverado.
| The Underground Diesel Performance compound-turbo kit includes the cold piping, a new stock turbo cover, and a TIG-welded steel coolant reservoir (with 14- to 18-psi Moroso adjustable pressure cap), which are all powdercoated to whichever color is requested. The hot pipe and downpipe are wrapped in an insulating material. All the fuel lines, oil lines, and clamps are included in the kit. The kit is based on a BorgWarner S475 turbocharger featuring a T6 flange.
