Centrifugal supercharger performance took off in the early 1990s largely due to the growing 5.0L Mustang movement. It wasn’t new technology but the packaging, performance, and price tag of centrifugal superchargers made it one of the most sought after modifications of the time. Thirty years later, we have seen a ProCharger supercharged Pro Modified successfully compete in the top door-slammer ranks, racing units have the ability to deliver over 3,500hp, and today there are dozens of different models designed to work with virtually any engine combination including motorcycles.
The successes and records of centrifugal superchargers in the NMRA ranks are well documented. The series has practically grown side-by-side with the crank-driven boost maker and this month, we tested the latest entry into the market. ProCharger has made a lot of noise with its F-3R-136 supercharger in the upper echelon of small-tire and Pro Mod, but it certainly hasn’t forgotten about the average guys and gals of the hobby.
Last winter they greeted the street market with the P-1X and D-1X head units, designed to be one step beyond their tried and true P-1SC-1 and D-1SC models. “It is hard to believe but those two superchargers were designed 18 years ago,” stated Mike Carlson, lead engineer at ProCharger. The units have received a few upgrades over the years, as Carlson says they haven’t been stagnant and both are highly successful in the modern market.
However, the market has driven ProCharger to look at increasing the capacity of both units. ProCharger’s CEO Ken Jones explained “it was obvious with today’s horsepower from the OEs that we needed to move with the market.” The company focused on increasing the efficiency and lowering the drive power of the supercharger so more flywheel horsepower can be realized. Thankfully with ProCharger’s fast moving growth they were capable of diverting resources to special projects like these two new models and not disrupt their production line.
Jones is a hands-on CEO when it comes to product development and he looked at their successes with the I-1 that debuted a few years ago as a guide for the P-1X and D-1X. The design objective with the I-1 was to create an efficient impeller across a wide operating range due to the unique transmission design. Carlson and his staff work with sophisticated computer modeling software; using blade angles and other aspects of the I-1 put them on the right path to creating the new impellers for the new projects.
The plan for the P-1X was to make the swap easy for installers and end consumers with the focus on matching the “boost-to-pulley” ratio of the other P-1SC units. By increasing efficiency there is a reduction in drive power to turn the supercharger and that shows up in more power despite the pulley (and ultimately the impeller speed) remain the same. End users can enjoy a clean and easy swap that cranks more power without the need to re-calibrate the ECU. And to add more luster to the P-1X, it just passed EPA testing for 50-state use.
The D-1X wasn’t restricted like the P-1X so Carlson and his team went for maximum efficiency and still house it in the D-1 series unit. “It isn’t just a new impeller but also a new backing plate and volute design,” shared Jones. And while the D-1SC is rated, rather conservatively, at 925hp (flywheel) and real-world use has shown it crack 1,000hp, the goal with the D-1X was to consistently make 1,000hp. As you will see in our test, a no compromise combination will surpass that number by a wide-margin with 1,000-plus horsepower at the wheels.
The larger units in the F-1 series superchargers will drop into the same brackets for the P-1 and D-1 series superchargers and can make 1,600hp. There are, however, other considerations in keeping the D-1 style blower—people’s wallets. Jones was happy to report, “it is a nominal cost to upgrade a D-1SC to the D-1X and it goes into the brackets without a problem.” It eliminates the need for a user to buy a completely new head unit and just upgrade their D-1 chassis with the D-1X setup.
“We were very comfortable with increasing the capability of the D-1X aero stage beyond 1,000hp without needing to go to the F-1 transmission, any sort of failure of an SC transmission is extremely rare,” Carlson informed us.
Of course the swap to a F-1A unit in either the 91mm or 94mm impeller is available when it is time to go quicker. The unit still fits in the D-1 brackets and uses the same 9-inch diameter volute. For most enthusiasts a F-1A-94 is plenty powerful as it pushes NMRA Renegade cars into the 7.30s at full weight and NMCA Xtreme Street rides into the 4.70s.
With a firm background on the D-1X story from Jones and Carlson, it was time to test the unit. Dez Racing, located in Seekonk, Massachusetts, helped us ensure the D-1X’s claimed power was legit. They have an in-house DynoJet chassis dyno, has extensive experience in the supercharged world, and we’ve worked with them dozens of times over the past 15 years to test other products.
The test mule needed to have a killer engine combination with great flowing cylinder heads and sturdy valvetrain, as well as an air-to-water intercooler. Of the dozens of potential customer cars to conduct this test, Mike Dezotell opted for a familiar buggy. Dubbed the Budget Brawler, Jim Coger’s 1989 Mustang LX coupe has seen its fair share of drag strip action in NMRA and local competitions.
Coger was fresh off winning a local 275 Radial race thanks to 4.80 runs with a larger F-1A-94. Its current combination is a 363ci powerplant built by Adam Secour. A Dart Iron Eagle engine block houses a steel crankshaft, billet connecting rods, and custom pistons with 10.5:1 compression. Topside, Coger went all-out with a pair of Trick Flow High Port heads that got the full treatment from Total Engine Airflow. A Trick Flow single plane EFI manifold is topped off with a Shearer Fabrications air-to-water intercooler and Holley EFI lid.
Belt slip wasn’t going to be a factor in the test because an ATF Speed gear-drive is responsible for spinning the supercharger. The unique aspect of the ATF Speed drive unit is that it is capable of holding either the F-1 or D-1 series superchargers. Though Brian Machie of Dez Racing said that shorter stands are required to get the proper engagement on the blower snout if they were going to run the unit on track. ATF Speed also built the TH400 transmission that sits behind the supercharged powerplant.
Franny McCarthy, the in-house racecar specialist at Dez Racing, swapped the supercharger in less than hour. We got lucky that the inlet pipe fit with just a minor adapter. We aren’t reporting baseline pulls as Dezotell preferred to keep the F-1A-94 dyno results on the down low. For D-1SC users who are looking for a comparison, Carlson said they picked up 55 rwhp with the same pulley sizes on an LS combination (740rwhp to 795 rwhp) and the better efficiency helped belt life by a wide-margin.
The initial dyno pull with the D-1X produced an impressive 960rwhp, but we knew there was far more left in the combination. As we smiled and laughed over its stout numbers, Machie opened up the laptop to communicate with the Holley EFI HP engine management system. He had pulled the timing back to a conservative 19 degrees instead of going full-tilt on the first hit.
The Holley EFI data log showed the supercharger was producing a peak boost of 18 psi, pretty sporty considering the racy nature of the engine package. “With that kind of boost, we could throw all of the timing into the engine and still be safe. We run 26 degrees of timing at nearly 30 psi with the bigger F-1A-94 without any problems,” commented Machie. Just to be safe, the timing was nudged up to just 22 degrees.
The car was cooled off, McCarthy filled the water cell with fresh ice, and Machie made another chassis dyno run up to the 8,600 rpm redline. The result was a stout 1,029rwhp—through a TH400 and a relatively loose torque converter. Dezotell weighed in on the results, “That has 7-second potential with that kind of power in that car with the transmission/torque converter setup.” So much for the 1,000hp flywheel rating that ProCharger advertises. And to throw it out there, the supercharger speed still has 3,000 rpm available before it reaches the 62,000-rpm limit.
In world where 1,000rwhp street cars are the norm and the stakes at the drag strip have never been higher, ProCharger continues to evolve its product line to ensure that any engine can enjoy the benefits of boosted power.