Nearly three years ago, ProCharger, one of the leading supercharger manufacturers in the racing industry, unveiled their all-new RaceDrive unit — a trick new supercharger gear drive positioned as an exclusive and integrated product designed for use with the company’s redesigned F-3 family of blowers being used in the most extreme of racing applications. At the time, those in the market for a gear drive system had few options, although a larger number of aftermarket manufacturers have since developed their own units. But the RaceDrive remains the only truly integrated design.
Since it’s unveiling, the RaceDrive for the F3A-121RD, F3R-130RD and the F3R-136RD superchargers has been quietly but certainly not secretly under continual on-track and dyno testing with racers whom ProCharger has forged relationships with over the years — including longtime NMCA racer Chuck DeMory Jr. in his Pro Street/Pro Mod 1968 Ford Mustang and NMCA Super Street 10.5W racer Mikey Rees in his third-gen Camaro.
Mere weeks after the reveal of the RaceDrive, ProCharger pulled the wraps off the new F-1X supercharger that soon took the X275 ranks and many other small-tire venues by storm. Then, at the 2013 PRI Show, the all-conquering F-1X was followed up by a new model, known as the F-1X-12, designed to take full advantage of the new NMCA, NMRA, and NMCA WEST Street Outlaw class specifications and to address the needs of the most hardcore F-1X users. The new model features a design strategy and degree of efficiency very similar to that of the much larger and more potent F-3 family, with a larger 12-inch volute and increased specifications across the board relative to the F-1X.
But little did anyone know, even among the decision-makers at ProCharger, that these two products — the RaceDrive and the F-1X-12 supercharger — would eventually become closely interconnected. And to that end, nor could anyone have guessed that this combination would lead the research and development team at ProCharger toward a largely untapped market in drag racing: dragsters.
ProCharger’s new gear drive unit was an answer to the call from customers across a number of drag racing disciplines who had supplied their input to the racer support staff, requesting not only an integrated gear drive for their increasingly-powerful race cars, but one that could operate a number of accessory systems, be easily serviceable, and also fit in any range of engine compartments without major modifications. ProCharger’s engineering team checked all of those boxes off in the design of the RaceDrive, delivering a piece that could effectively transfer all of the power from the crankshaft into the gear drive unit, spinning the supercharger without any need for a belt or a chain, both of which presented reliability issue in applications making well in excess of 2,000 horsepower — Outlaw Drag Radial and Outlaw 10.5 cars, Pro Mods, and the like.
“With the state of gear drives at the time, we wanted to take things a step further beyond the products that were out there with our own design for high-horsepower applications,” says ProCharger’s Jason Medlin. “Part of our focus was on accessory drives, because at the time there weren’t a lot of options that didn’t require some custom engineering. We were able to take all of these ideas, and bring it to our gear drive where we have three provisions for accessories, which, when we were designing it, no one had that just yet. But part of our initial design process was to give our customers more choice.”
We wanted to have something that would get into the higher horsepower levels, something that was integrated, and do it all in a smaller package. – Jason Medlin
One of the key design attributes of the RaceDrive is that, unlike other designs (albeit not all third-party designs) where the supercharger is more or less in-line with the centerline of the crankshaft, ProCharger has situated the blower closer to the engine and higher up in the engine compartment, thereby avoiding issues with the rack and pinion steering, radiators, or other vital components out in front of the engine.
By the numbers, the F3-compatible RaceDrive measures 15-inches from the face of the engine damper to the air inlet of the blower, 7.5 inches from the center of the crank to the blower inlet shaft centerline, and 13.5 inches of overall height from the center of the crank to the top of the gear case. This makes it incredibly compact for what it is.
“To put a gear drive on a car, it’s typically taken somewhere in the range of 18-inches in front of the crankshaft, where ours at this point is about 14 to 15,” says Medlin. “Because our RaceDrive is shorter and it brings the supercharger up, it makes it possible to get it into cars that wouldn’t otherwise be able to run this kind of setup. They could run a side-slinger, but then you get into weight distribution issues and things like that.”
Internally, the RaceDrive is entirely gear-driven, with two gears transferring the power from the crank up to a pair of gears at the blower connection point. Another key feature is the ability to change the gear sets by removing the front cover and replacing the 10-spline quick change gear set. In all, more than 40 different gear sets are available for any range of boost levels.
Similar to other gear drives on the market, the RaceDrive uses a pair of couplers to connect the unit to the front face of the engine damper to transfer the torque of the crankshaft to the blower. Between a set of steel couplers is a single, hard rubber couple that locks the two together while reducing vibration back and forth between the engine and the blower.
A New Approach: The Dragster
When the RaceDrive was first brought to market, it was intended for, as alluded to earlier, 3,000-plus horsepower race cars using the biggest and baddest blowers on the market. After the initial unveiling and subsequent testing, Medlin, who runs a dragster himself, began to entertain the idea of re-packaging the RaceDrive for less powerful engine combinations like those used in Top Dragster and Top Sportsman.
“This was a market that we hadn’t really gone after a whole lot,” says Medlin. “We had some customers running our standard side-slinger blowers in those classes, but nothing on a larger scale. The big F-3 was just too much blower and too much horsepower to put into a 1,900 to 2,000 lb. race car.”
Medlin began to champion the idea of scaling the RaceDrive down to pair with the new F-1X-12, providing a more power-suitable combination for the fast bracket racers. He believed that the F-1X was truly the blower that was needed for this style of racing, and soon, with the help of Joe Hessling at Advanced Product Design — an Ohio-based carburetor and fuel management specialist facility that had already equipped a number of dragsters with ProChargers in the past — it soon became a reality.
It’s the physical size and layout of the RaceDrive that makes it appealing to the dragsters guys — because it’s more compact and they can fit it in the cars easier without making major modifications. – Jason Medlin
The F-1X-12 RaceDrive uses the same transmission and 12-inch present in the larger F-3 unit, but essentially has the smaller impeller wheel for the smaller blower.
As Medlin tells us, it’s the 1,700 to 2,000 horsepower range that this package really caters to, and for Hessling, the F-1X-12 presents a way to get that kind of power and run deep into six-second territory without hurting parts by using nitrous oxide, which has been the general route many Top Dragster racers have gone.
“What this whole project has done, from the very early development of the F-3 RaceDrive, is help us to bring this technology to a whole new genre of people that may have never thought of a ProCharger as a power adder for their race cars,” explains Medlin.
The new F-1X-12 RD RaceDrive is currently in production and ready to order from ProCharger or via authorized ProCharger dealers. The F-3 unit, designed for the F-3 121, 130, and 136 superchargers, has been green-lighted after extensive on-track testing and is slated to go into full production in 2015.
APD And The F-1X-12
Already with a solid working relationship from past projects, Hessling and his team at APD have worked with ProCharger to test the new RaceDrive on an in-house car of theirs, as well as that of customer Greg Curtis on his Ohio-based, American Race Cars-built Top Dragster. Hessling has mounted up roughly a dozen cylinder head-mounted, side-slinger blowers on customer cars in the past, and saw the RaceDrive as a perfect solution to eliminate the blower belts and bring the entire package inside the framerails, describing it as a much cleaner setup all-around.
“There are a lot of guys in Top Dragster, Top Sportsman, and the fast bracket racing world that are tired of hurting pistons and other parts in their nitrous motors. In between rounds you’re changing bottles, changing jets, pulling spark plugs — but the ProCharger setup, once you have it all ironed out, is a much simpler combination to operate and maintain,” says Hessling.
Hessling’s dragster, a 250-inch wheelbase American chassis, and Curtis’, a 270-inch car, both had enough room to contain the RaceDrive and the F-1X-12 without any special modification. As carburetor specialists, both cars have been set up in a single blow-through configuration, with a 1,250 cfm, modified Holley Dominator on Hessling’s and a billet main body carburetor of the same size on Curtis’ atop 540-inch big block Chevrolets with Brodix cylinder heads. According to Hessling, the engines were run conservatively on the dyno at APD, and at 18 lbs. of boost with a relatively low gear ratio of 1.25:1, produced 1,930 horsepower and right around 1,300 ft/lbs. of torque.
With this combination, Curtis has been 4.01 to the eighth-mile and 6.22 at 220 miles per hour out the back, while Hessling, who has only put a few shakedown laps on his car thus far, has been 6.32 at 221.
“What’a amazing is, we’re so far on the underside of what these things will do with gear ratio and the way we’re running these motors with compression and everything — these are very safe, conservative setups,” says Hessling.
Hessling and company developed the blower bracket that you see on his race car, which incorporates a bracket for the vacuum pump and fuel pump, as well, which are both driven off the RaceDrive itself.
“Says Hessling in closing, “It’s just an altogether better setup — the crank is supported, there’s no potential for a broken belt, or a need for a blower inlet tube like we’ve used in the past.”
For racers coming from nitrous oxide combinations, ProCharger’s Ken Jones sees centrifugal superchargers as a multi-fold advantage.
“In what other way can you increase horsepower, hurt fewer parts, and decrease your between-round maintenance?” Jones asks. “It allows you to spend less time working on the race car and more time with your family. We’d like to think that it increases the enjoyment of racing.”
So will we see a revolution in bracket racing with racers shifting toward superchargers and away from nitrous or simple brute cubic inches? If the performance that Hessling and company have already shown, and the incredible interest from racers that ProCharger has seen are any indication, this technology once reserved primarily for heads-up small tire cars just might be the wave of the future. Because as Jones and Hessling see it, it’s a no-brainer.
Photos by Mary Lendzion and ProCharger