For decades, gearheads have been searching for one thing: more power. Whether it’s from a stock engine that needs to be sauced up, or from a modified engine that needs an extra helping of spices, more power is often the first thing that an enthusiast looks for when it comes to improving the smiles-per-gallon ratio of a hopped-up vehicle. For nearly 30 years, ProCharger has come to enthusiasts’ rescue with its well-engineered centrifugal supercharger systems.
But—as always—more power is better. Let’s say you’re an enthusiast who invested in one of ProCharger’s P-1SC-1 supercharger systems to pump up your ride, and now you’ve decided you’re ready for more power. That’s where the subject for this article arises.
P-1SC-1 compressors are ubiquitous in the performance world, synonymous with improved horsepower and massive gains over stock horsepower levels on just about any engine platform out there. But as with any performance modification, they have a ceiling: that horsepower level where they reach the point of no return, tapped out to the point where adding more boost simply doesn’t make any more power due to aerodynamic inefficiencies.
Once any compressor–whether it is a centrifugal supercharger like the P-1SC-1 or even a turbo–exceeds its efficiency range, it begins to add excessive heat to the air charge. It’s because of this heat increase that the enthusiast eventually reaches that spot where it makes more sense to upgrade the compressor than it does to install a smaller pulley.
When To Step Up
According to ProCharger’s Erik Radzins, the P-1SC-1 is good for somewhere around 825 crankshaft horsepower; no slouch, for sure. But in today’s world of 1,000-horsepower street cars, it’s certainly the company’s entry-level piece. Enter the D-1X, originally released in 2017.
“The D-1X is good for 1,000 horsepower all day long,” says Radzins.
Why is this significant? Perhaps because the D-1X can be used in the same brackets, with the same tubing arrangement and all of the same supporting gear as your existing P-1SC-1 supercharger. As long as you have enough fuel—and your pistons and rods won’t exit stage left with more power applied to them—the D-1X is a direct swap for the P-1SC-1 compressor housings. Each of the company’s P-series bolt-on kits can be had with a D-1X in place of the P-1SC-1 supercharger.
But it’s most significant because of a recent trip we made to the ProCharger skunkworks in Lenexa, Kansas, just outside Kansas City (and home to some of the best food we’ve ever eaten, but that’s a discussion for another day).
During part of the visit, we were able to witness the crack ProCharger service team take an existing P-1SC-1 compressor and turn it into a D-1X in just a few hours by replacing several of the pieces. It was the perfect time to drop the D-1X’s upgraded parts and pieces into place to improve the compressor’s capabilities, as the tantalizing allure of more horsepower couldn’t be ignored. The resulting all-new supercharger gave this particular customer the capability for an additional 175 horsepower, for substantially less cost than a complete supercharger upgrade.
Now, you might think that this upgrade requires most of the compressor’s components to be changed out, but that’s not the case at all. There are only three main components which are swapped out to take a supercharger from a P-1SC-1 to a D-1X: the volute, the impeller, and the backing plate. Since all of these pieces need to be removed anyway to replace the supercharger’s seals, it’s a perfect time to invest in an upgrade—and a bunch more power—by stepping up to the D-1X configuration.
“One of the advantages to using the D-1X design is that it’s still self-contained and offers the helical gearset,” says Radzins. “So if your existing supercharger has these components, you can drop a converted D-1X right into place.”
What’s The Diff?
Although the P-1SC-1 (and D-1SC) configuration is a perfectly capable supercharger that’s a solid performer for many enthusiasts and offers plenty of power potential, it’s also two decades old, with impeller design and internal airflow capability reflecting that, although it was state-of-the-art technology at the time it was released to the public. The self-contained gearbox in this supercharger has proven itself over millions of miles and thousands of installations, but as with most performance-oriented products, there comes a time to redesign it using current technology and the results of many hours of research and development. But what does the typical gearhead do when it’s time for more?
So how does the D-1X make more power out of a unit that’s the same overall size, you ask?
“We redesigned these units with greater efficiency and also reduced the parasitic load, which means it creates less heat and requires less power to spin the supercharger’s impeller,” says Radzins.
The D-1X is good for 1,000 horsepower all day long—Erik Radzins, ProCharger
The D-1X’s impeller will spin up to 62,000 rpm safely, and since the supercharger’s transmission remains the same proven unit, durability is not an issue whatsoever. The D-1X maxes out at 32 psi of boost pressure, which is more than enough for all but the most insane street cars. And at the massive power level at which the D-1X shines, the moniker “street car” becomes highly debatable anyway. At least in this humble author’s opinion.
Using its on-site test lab and modern machining capability, ProCharger created and whittled out several wheel designs, thrashing them on the supercharger dyno before settling on the final piece for the D-1X, which features optimized fin angles and contours tailored to maximize the compressor’s performance.
Optimizing the impeller’s fins also required the creation of an all-new volute design to match up perfectly with the impeller. The combination of these two improvements allows the D-1X to make more power per pound of boost. Even with the same 9-inch volute diameter as the P-1SC-1, the D-1X adds 300 cfm of additional airflow capability.
It does this through an additional .200-inch added to the inducer diameter (measuring at 3.570-inch as compared to the P-1SC-1’s 3.370-inch), allowing more airflow into the impeller. The exducer diameter also increases from the P-1SC-1’s 5.25-inch diameter to a whopping 6.20-inches. By changing the number, configuration, and shape of the blades on the impeller, and increasing the exducer diameter, tip speed is improved, giving the supercharger more efficient performance. The increase makes this upgrade a no-brainer.
The actual process to change the P-1SC-1 into a D-1X is about as simple as it gets. The three new components drop right into place, and you’ve got what’s basically a brand-new, more powerful supercharger for a fraction of the cost of replacing the entire unit. There is no doubt that an upgrade to the D-1X is a wise choice for P-1SC-1 owners, especially if the base powerplant has the capability to accept more power without failure. Follow along with the photos and captions for more details.