In the previous two articles about the Red short-block, followed by the top half of the engine, we showed you Pro Line Racing’s latest big-block engine design coming to life. Now, we need to show you what kind of power all that research and development is worth.
But first, we have to show you what goes into making that power, because an engine like this isn’t designed for atmospheric pressure alone. In a previous article, we mentioned that this engine was destined to power Dragzine’s BlownZ28 project, and that project is destined to compete in Limited Drag Radial (LDR) trim, which means the choice of power adder is limited by a rulebook.
Since the car’s owner and driver, as well as the support team, are intimately familiar with supercharged combinations — specifically centrifugally supercharged combinations — in competition, it only stands to reason that they would go with what they know for this project. Looking at the rulebook, LDR allows the ProCharger F-3R with a maximum impeller diameter of 139mm (AKA: the F-3R-139). However, that isn’t the model the team decided on.
“Limited Drag Radial has a max blower size of 139mm, however, our 136mm wheel is our newer, higher efficiency design compressor,” explains Erik Radzins, ProCharger’s Director of Communications and Calibrations. “With the F-3R being a proven, rugged, reliable unit for years now, at this power level it was a no-brainer.”
Choosing a blower at this level of performance is far more involved than looking at the rulebook and picking out the biggest blower allowed. While the rulebook might guide the selection, ultimately, it comes down to matching the power adder to the combination. “The truth is, the F-3R-136 would still be the best option for this combination, even if the rulebook didn’t exist, since it is our highest power and most efficient blower for this given power level, engine size, and racing application,” Radzins says.
Diving Into the ProCharger
Looking at the ProCharger lineup, there are a number of variables that you must first understand, in order to know what you are getting. The most obvious delineation in ProCharger’s lineup is a street supercharger versus a race supercharger. “The street blowers use a different step-up ratio internally [the gear ratio between the drive pulley and the compressor shaft], and also have helical gears as an option for quieter operation,” explains Radzins.
“The race units have a bunch of differences due to the higher amount of horsepower they support. Items such as compound bearings, different machining processes, larger gears, shafts, and bearings — you name it. But no matter if it’s a street or a race unit, the gear cases and impellers are 100-percent billet, and all units feature self-contained oiling.”
While there are both street and race blowers within ProCharger’s F-series supercharger lineup, the F-3R is definitively in the race category. As an F-3R, the volute diameter is the same as all of the superchargers in the F-3R lineup at 12 inches across — a spec which really hasn’t changed in over a decade, even amid all of the other technological changes to the lineup.
Combined with a billet compressor wheel with a 5.350-inch inducer and 7.220-inch exducer, the F-3R-136 is capable of moving 4,000 cubic feet per minute of air. “The impeller is made from 7075 billet aluminum, and is 100-percent designed, machined, and balanced in-house. It’s relatable to many of our other high-efficiency designs, such as the P-1X, D-1X, F-1A-94, F-1X, and even the F-4X,” says Radzins.
With the most aggressive internal step-up ratio in the ProCharger lineup of 5.63:1, the supercharger is rated for a maximum impeller speed of 72,000 rpm. Those numbers, in conjunction with the engine’s maximum RPM, will become important when calculating the drive sizes for this supercharger. Not only to ensure you’re not over-spinning the blower, but to make sure the blower is operating in its most efficient range — which might not be the “max boost” listed on ProCharger’s spec sheet.
“Boost is only a measure of restriction, and the 50psi number [listed on the spec sheet] is a base number we’ve tested at. On some combinations the -136 can make more, others less; it really just depends on the engine it’s feeding. We have an amazing staff to get you into the correct blower for the application and guide you on the blower speed needed to produce the best results,” explains Radzins.
Driving the Beast
When it comes to actually turning a behemoth such as an F-3R, there is no such thing as a ribbed serpentine belt drive. No number of ribs on a belt are going to handle the kind of power we’re talking about in this realm. Back in the day, cog belts were your only option for that kind of power, but were still inherently limited by being a belt. Thankfully, it’s 2021 and much, much better options now exist in the blower drive arena.
“Gear drives have been a game-changer for centrifugal superchargers and their maximum power potential,” says Radzins. “Belt drives just aren’t capable of supporting the kinds of maximum power, or even just reliable power, our blowers are capable of supporting – 3,500-plus. Now with gear drives being commonplace, it’s really helping us push the envelope of what a ProCharger can do.”
By allowing the superchargers to spin harder, designers and engineers were given a larger envelope to work within when designing components. Combine that with modern engine technology, and centrifugal supercharging has seen a boom in the big-power arenas. “The real change came from impeller design, RPM, durability, and working with great engine builders to really dial in the engine to move the air as efficiently as possible. You can have a great supercharger, but if you can’t drive it hard enough, and the cylinder head won’t flow the air, it won’t really matter. Thanks to some amazing engine tech these days, the superchargers really get to shine,” says Radzins.
Gear drive units, as the name implies, provide an insanely strong, durable mechanical link between the engine’s crankshaft and the input shaft of the supercharger. Instead of a crankshaft pulley connected to a supercharger pulley by a belt, you now have a series of hardened steel gears. Like the previous pulley and belt setup, however, to change the speed of the supercharger, you now just change the sizes of the connecting gears.
“On a purpose-built race application, gear drives are generally the way to go unless rules dictate they can’t be used,” Radzins says. “I mean there are loads of Top Dragsters still using belts at the 2,000-horsepower level. However, we have seen gear drives enter the picture starting at 1,500hp or so, for racers that have the room, and just want to run directly off the crank.”
The only downside of a gear drive can be the actual size of the gear drive unit itself. “On a street car, spacing is the number-one issue. But, that’s about it, since we have systems that allow alternators to be run, and some can even adapt power steering as well,” explains Radzins.
While there are a number of manufacturers of gear drive units on the market, we opted for ProCharger’s own CrankDrive system. It has been designed with a ton of unique features that make it the perfect choice for BlownZ28. The lightweight design positions the supercharger unit to provide additional steering and chassis clearance, and allows the engine to be rotated in both directions, with the drive installed, for between-round maintenance. Additionally, the gears themselves are a quick-change design, to allow for easy swaps in the pits.
Managing the Boost
When it comes to managing all the goings-on of an engine making this kind of power, you’re in rarefied territory. So it only stands to reason that the team sticks with the setup they know works at this power level, in this application as well. So for that, they turned to the tried-and-true FuelTech FT600 engine management system.
We’ve covered the system in-depth previously here, but most of it bears repeating. First, is the packaging. The fact that the FT600 is an ECU and digital display all in one single unit really belies how powerful it is as an ECU. It offers extremely high-resolution 32×32-cell fuel and spark tables, which all have user-definable programming points — if you want to map every 250 rpm from 1,000 to 9,000 rpm, you can.
When you pair that powerful ECU with FuelTech’s FTSPARK capacitive ignition box, capable of 750 millijoules of spark energy per event, you’re talking about putting out a spark with 140 amps of energy. The team paired the FTSPARK ignition box with FuelTech’s CDI Racing Ignition Coils for a coil-per-plug setup which will be able to ignite the most difficult fuels in the highest of cylinder pressures.
Power to the Rollers
One thing about an engine and setup of this caliber, is that ProLine traditionally doesn’t rely on dyno numbers for final tuning. In fact, they don’t use an engine dyno at all. Since their engines are generally built for a specific purpose, they choose to test them installed in the vehicle. And even the chassis dyno is just validation and to get a solid baseline for the racetrack — which is where they do their final tuning.
Performance Where It Matters: On Track
One of the big reasons that Pro Line Racing relies on track numbers as opposed to just making big graphs on the dyno, is because that is where races are won. The chassis dyno is a great tuning tool, to make sure everything is on the right track, but the track itself is the ultimate equaizer. Between the framerails of BlownZ28, at a 2,950-pound race weight, the car’s best eighth-mile pass comes in at 3.95 seconds, trapping at 182 miles per hour, with a 1.01-second 60-foot time (telling you the car was working incredibly well). If we do some quick calculations based on trap speed and car weight, we get a number about 80 horsepower higher than the peak on the dyno.
Finding a chassis dyno capable of handling the level of power expected to be produced here isn’t something you do by looking in the yellow pages. Luckily for us, FuelTech has a Mainline ProHub 4000 dyb-style dynamometer capable of handling 9,600 lb-ft of torque and wheel speeds north of 300 miles per hour. So with the Pro Line Red engine bolted into the BlownZ28 chassis, the ProCharger F-3R-136 mounted to the crankshaft, and the whole shebang bolted to FuelTech’s hub dyno, things were about to get real.
FuelTech’s Tech Director, Luis De Leon suited up and hopped into the car with the laptop, and the combination was brought to life. While the Red engine might be a new beast, as far as the tuning is concerned, the team felt they had a solid baseline tuneup to start with. And boy did they ever, with the first power pull netting 2,275 horsepower. Not bad for a baseline.
With a few changes in the FT600, the team reset and made another pull. De Leon was rewarded with 2,334 peak horsepower on that pull, but knew there was more in the tuneup. A little more keyboard massaging and another pull later, there was a new high score on the board, 2,486 horsepower. However, De Leon still saw some “cleaning up” he could do in the tables and made some more changes.
With a few areas of the map cleaned up in hopes of smoothing out the power curve, the crew made yet another pull. Obviously, De Leon knows what he is doing on the keyboard, and it was proven with the highest number of the day. An additional 70 peak horsepower for a number of 2,552 horsepower at 7,525 rpm with the engine winding out to 8,500 rpm with a nice smooth power delivery curve.
De Leon wasn’t done, with a little more massaging, he picked up another 100 peak horsepower, seeing 2,652 horsepower at 6,300 rpm. De Leon wanted one final pull after a little additional tweaking. This time, the dyno showed an additional 40 horsepower increase, with a final reading of 2,694 horsepower at 5,600 rpm and monster 3,621 lb-ft of torque.
2,694 horsepower out of a 572-cube engine comes out to just over 4.7 horsepower-per-cubic-inch, from a 9,000 rpm-capable platform which has been designed to be an affordable option in the world of huge-power drag racing. The numbers all speak for themselves — with the assistance of ProCharger, FuelTech, Dart, and a host of others, Pro Line Racing’s Red engine program is a resounding success.