A compound turbo setup on a Duramax pairs two turbos in series — a smaller “primary” or “draw-through” turbo feeds air into the factory or upgraded turbo. The result is dramatically improved spool response, lower EGTs, and the ability to support 700–1000+ rwhp on a built engine.
HOW COMPOUNDS WORK
- Ambient air enters the small primary turbo first — compresses to 10–15 psi
- That pre-compressed air feeds the factory or upgraded secondary turbo
- Secondary turbo compounds the pressure — total boost of 45–65+ psi possible
- Result: faster spool, lower EGTs, massive power potential
BENEFITS
- EGT reduction of 200–400°F compared to single large turbo at same power level
- Better throttle response — primary turbo spools quickly from low RPM
- Can support extreme power levels that exceed single-turbo capability
- Cleaner air delivery at high altitude where single turbos struggle
WHAT YOU NEED FOR COMPOUNDS
- Built or factory Allison 1000 (stock holds ~600 rwhp in good condition)
- CP3 conversion on LML — CP4 cannot flow enough fuel at high power
- Quality lift pump (FASS 165 GPH or higher)
- EFI Live or Autocal tune written for compound turbo
- Upgraded intercooler — factory unit cannot handle compound boost pressure
- EGT gauge — critical for tuning compound setups
POWER STAGES
- Stage 1: Compounds + tune: 550–650 rwhp
- Stage 2: Compounds + injectors + built Allison: 700–800 rwhp
- Stage 3: Full build: 1000+ rwhp possible on a built LBZ/LMM