A Little Background On Billet Wheels, Starting With Cast Versions

What is a billet compressor wheel? Better yet, what is a cast compressor wheel? Cast from aluminum, cast compressor wheels are standard in most turbocharger applications. A great example would be the S300 SX3 and S400 SX lines of turbos from BorgWarner, which offer cast wheels as standard equipment. The cast wheel is easy to produce in mass quantities and has proven—for more than half a century—to be highly reliable. Knowing this, it’s easy to see why most turbo manufacturers use cast wheel technology. Here at Smeding Diesel, the cast compressor wheel is the most cost-effective option we offer.

Thicker And Heavier

Though rock-solid reliable, the cast wheel’s design leaves much room for improvement—especially if the goal is performance. The first performance hindrance exists in the blades. In order for a cast compressor wheel to enjoy adequate strength, its blades have to be cast relatively thick—and they’re much wider than what you’ll find on a billet wheel. The same goes for the compressor hub, the section in the center of the wheel that allows the threaded end of the turbine shaft to pass through (and that accommodates the compressor nut). The hub on a cast compressor wheel is much thicker than what you’ll see on a billet wheel. Essentially, a cast wheel is thicker and heavier than a comparable billet version.

Billet Wheels

Roughly 15 years ago, as aftermarket turbo manufacturers began to seek out their own compressor wheel designs, the use of billet compressor wheels started to take off. For these smaller businesses, which didn’t have the capability to cast their own wheels or that didn’t need to mass produce them, a CNC-machined, billet compressor wheel was the most effective way to develop better performing designs. And being that billet wheels are typically made from a forging, they provide improved strength over cast-aluminum—but that’s only the beginning. Because a billet wheel is made from a superior material, its hub and blades can be considerably thinner without sacrificing strength and durability. Summing things up: billet wheels are both lighter and stronger.

Thinner And Lighter

In addition to a lighter wheel aiding spool up, the tighter hub on a billet compressor wheel makes it possible to utilize longer blades. The more surface area you have on the blades, the more air you can bring into the turbo—and with more airflow comes more horsepower potential. Further increasing performance, many billet wheel manufacturers have developed aggressive blade pitches and contours in an effort to wring every last drop of airflow out of their designs. The combination of forged-aluminum material, longer blades, different blade counts, unique blade angles, and a lighter overall package has made the billet compressor wheel a popular seller throughout the turbo world.

SXE-R Billet Wheels

Going beyond the standard cast wheel and our billet wheel options, we offer a competition series billet wheel coined the SXE-R. These competition-level, point-milled compressor wheels are lightweight and designed to maximize performance beyond what the standard billet option provides. So how is the SXE-R different? Its swept blade design means that the blades are curved. Sweeping the blades increases their length for an even bigger bite of air over what billet offers. But not only that, the swept blade design improves its strength. And while both our billet and SXE-R wheels benefit from an integrated compressor nut, the SXE-R design boasts a thinner hub—which provides for longer blades and less overall weight.

Thinnest, Lightest And Highest Flowing

Our goal with the SXE-R line was to produce a compressor wheel that allows a turbo to spool like a smaller version while at the same time flow the kind of air you would expect a much larger turbo to move. We think we’ve done that thanks to the SXE-R incorporating the most advanced materials and designs we’ve developed to date. In testing, our SXE-R wheels have proven capable of flowing as much as 20-percent more than the standard billet wheel offering—our standard billet wheel already having proven capable of outflowing a comparable cast wheel by 10 to 15-percent.

Cast, Billet, Or SXE-R—Which Is Right For You?

There is a reason we offer three different compressor wheels for virtually every turbo we sell, and here’s a brief rundown as to why. For all-out performance and exceptional spool up, the SXE-R wheel will meet your needs, and then some. For added performance and improved spool up on a budget, the billet wheel can’t be beat. For affordable performance and time-tested reliability, cast still has its place.