Duramax VVT Upgrades:
The 2004.5-2005 LLY was the first model Duramax to be equipped with a Variable Vane Turbo (VVT). VVT technology provides quicker spool-up, better EGT control, and better overall boost control. This is also commonly referred to as a VGT or Variable Geometry Turbo.
To understand the basics of a VVT or VGT technology take a look at this VIDEO on YouTube.
The stock Duramax VVT turbo from 2004.5 until 2010 is similar. Slight changes to each model (LLY, LBZ and LMM) were made in compressor size, aspect ratio, blade profile and other features. Despite these changes, you will find the same peak power potential of approximately 530 RWHP. As a Duramax performance enthusiast this is probably just not enough power to keep your interest for long.
There are many upgrade options on the market. Deciding which one is the best for you can be tough. An endless amount of forum threads and user stories makes it challenging to decipher fact from opinion.
Stealth 64 Turbo Product Links: