Turn-Key Twin Turbo Systems - Both Turbos Included
Complete compound turbo kits provide EVERYTHING: small turbo, large turbo, manifold, all piping, mounting hardware—the complete twin-turbo solution.
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These turn-key packages are perfect for owners starting from stock or wanting to replace their entire turbo system with perfectly matched compound components. Get 200-300°F cooler EGTs, instant response, 600-800+ HP capability, and the ultimate towing performance in one comprehensive package.
Small AND large turbos - complete system
Turbos sized to work together optimally
Manifold, piping, mounting, hardware - no guesswork
200-300°F cooler EGTs, 600-800+ HP, zero lag
What's Included: Small primary turbo, large secondary turbo, manifold, ALL piping, ALL mounting hardware, oil lines, complete installation package.
Building in stages? Explore related categories: Add-A-Turbo Kits, S300 Single Turbos, S400 Single Turbos, 6.7 Cummins Exhaust Manifolds.
Best For: Stock turbo setups, complete overhauls, owners wanting perfectly matched compound system without piecing together parts.
A compound turbo kit uses two turbochargers working together, typically a smaller high-pressure turbo and a larger low-pressure turbo. The smaller turbo provides quick spool and low-RPM response, while the larger turbo supports high airflow and boost at higher RPMs. This setup delivers faster spool, higher horsepower potential, and lower exhaust drive pressure compared to a single turbo system.
Kits are available in configurations based on your power goals:
S300/S400 Complete Kit (Example: S366 small + S475 large):
S300/S300 Complete Kit (Example: S362 small + S369 large):
S400/S400 Complete Kit (Example: S475 small + S483 large):
Quick guide:
Power depends on turbo sizes and supporting mods:
S300/S300 with moderate mods: 500-650 HP, great daily/tow balance
S300/S400 with full mods: 600-750 HP, best for heavy towing and performance
S400/S400 with extreme mods: 750-900+ HP, competition-level
Real examples:
Beyond numbers: Compounds make power smoothly, usably, and with 200-300°F cooler EGTs that protect your engine.
Compound turbo setups are designed for serious diesel performance. Benefits include quicker spool-up, improved throttle response, higher boost capability, reduced exhaust gas temperatures, and better overall efficiency under load. They are ideal for towing, racing, and high-horsepower diesel builds where a single turbo becomes a restriction.
Yes, when properly sized and tuned, compound turbo kits can work very well for towing and street-driven diesel trucks. The small turbo improves low-RPM response and drivability, while the larger turbo handles airflow under load. Many compound systems are specifically designed to balance daily driving manners with heavy towing and performance use.
Complete kits include BOTH turbos. Add-a-turbo includes only the large turbo.
Complete Compound Kit:
Add-A-Turbo Kit:
Which should you choose?
EVERYTHING for a twin-turbo compound system—both turbos and all components.
Complete kits include:
What you'll need (not included):
Why complete kits are best: No guessing at turbo sizing compatibility, no hunting for parts, no mismatched components. Everything is engineered to work together perfectly.
A larger single turbo lowers EGTs by increasing airflow, but it comes with a tradeoff — larger turbines require more exhaust flow to spool, which means lag and reduced low-RPM response. Compound turbos achieve the same airflow increase without that penalty because the small high-pressure turbo spools quickly on modest exhaust flow while the large low-pressure turbo handles the high-load volume. Additionally, two-stage compression at lower individual pressure ratios adds less heat to the charge air than a single large turbo compressing to the same final boost pressure in one stage. The result is more airflow, cooler charge air, and better drivability than a comparably capable large single turbo can deliver.
On a complete compound kit, yes — the existing turbo is removed and replaced by the small high-pressure turbo included in the kit, which is matched specifically to the large secondary turbo. On an Add-a-Turbo kit, your existing turbo stays in place and becomes the high-pressure stage. The Add-a-Turbo path is the right choice when you have already invested in a quality upgraded single turbo — S300, S400, or VGT — and want to convert to compounds without losing that investment.
Compound turbo kits require 4-inch or 5-inch turbo-back exhaust from the large secondary turbo outlet. The large turbo flows significantly more exhaust than a stock or single-turbo setup, and restrictive exhaust downstream of the large turbo creates backpressure that limits how efficiently it can spin. If your truck already has a 4-inch or larger exhaust from a previous upgrade, it may be reusable depending on the routing — verify with your installer. If it is still on the stock exhaust, plan for an exhaust upgrade as part of the compound build.
A custom compound build requires sourcing two turbos separately, fabricating or sourcing a manifold, bending all crossover piping, making custom oil lines, and verifying that every component clears the specific engine bay's obstacles. For a skilled fabricator this is a viable path. For most owners, the Diesel Power Source® kits eliminate weeks of work and the risk of turbo mismatch by delivering a pre-engineered system where every component was designed to work together in your specific truck. The cost difference between a kit and a quality custom build is typically minimal once fabrication labor is factored in.
For most compound kit configurations that replace the factory turbo system, the truck would not pass a visual emissions inspection in states that require it. The Add-a-Turbo kit for the 6.7 Cummins is the exception — it retains the factory VGT and all emissions equipment while adding the large secondary turbo upstream, making it an emissions-compatible compound option for trucks that must remain street-legal in regulated states. Contact the Diesel Power Source® team to discuss your specific situation and state requirements.
