In the world of diesel performance, we’re always chasing the perfect setup. We want the instant throttle response of a small turbo for stoplight to stoplight driving, but we also want the massive top end power that only a large, high flowing turbocharger can provide.

Usually, you have to pick one. If you go too big with a single turbo, sometimes you’re dealing with turbo lag. If you stay too small, your EGTs would go through the roof the second you hook up a trailer.

What Exactly Are Compounds?

A common misconception is that compound turbos are the same as "Twin Turbos" on a gas powered V8. On a traditional V8, each turbo usually handles one bank of cylinders. In a Compound setup, like the ones we build at Stainless Diesel, the turbos work in series, one feeding the other.

1. The Atmosphere Turbo (Large): This is the big guy. It takes in fresh air from the filter and compresses it.

2. The High Pressure Turbo (Small): This turbo takes the already compressed air from the atmosphere turbo and compresses it again before it enters the engine.

By the time the air hits your intake manifold, it’s been through two stages of compression. This results in a massive boost without overworking either individual turbo.

The Best of Both Worlds: Spool vs. Flow

The magic of a compound setup is how it handles the power curve. Because you still have a smaller high pressure turbo (like a 5Blade Mafia™ S300) close to the exhaust manifold, it spools up almost instantly. You get that "off the line" grunt that makes a diesel fun to drive.

As the RPMs climb and the small turbo reaches its limit, the larger atmosphere turbo (like an S475 or S480) has already started humming. It takes over the heavy lifting, providing the massive volume of air needed to keep your EGTs cool, all while making big horsepower numbers.

Why You Can’t Just "Slap On" a Huge Single Turbo

We often get asked about running a massive single turbo, like our S468 T-4. While that’s a beast of a turbocharger, we explicitly note: “Not recommended for single turbo usage on street applications.” Why do we say that? Because without the help of a smaller charger to get things moving, a huge single turbo will suffer from "surging" and turbo lag at lower RPMs. In a compound setup, that S468 becomes a perfect partner, acting as the high pressure stage that provides incredible mid range and top end pull without the low end sluggishness.

The Stainless Diesel Advantage: Plumbing and Heat

Compounds are only as good as the plumbing that connects them. At Stainless Diesel, we focus on the efficiency of the hot pipe (the pipe carrying exhaust from the small turbo to the big one).

Our stainless steel construction ensures that you aren't losing heat. In a compound setup, heat is energy. By retaining that heat within our shell molded stainless manifolds and high flow piping, we ensure the atmosphere turbo spools as quickly as possible.

Is a Compound Setup Right For You?

If your truck is a dedicated workhorse that tows heavy, or a street truck that needs to be reliable enough for the daily commute, but fast enough if you wanted to take it for a pass at the track, a compound setup is the answer.

The Benefits:

• Lower EGTs: More air means cooler combustion.

• Wide Power Band: Power from idle to redline.

• Better Towing: No more hunting for gears to keep the turbo spooled.

Ready to Double Up? Get a compound kit

Building a compound kit requires precision. From choosing the right 5Blade Mafia™ turbochargers to ensuring your oil lines can handle the flow, we’ve got the kits and the expertise to help you build a monster.