Regardless of the manufacturer’s name, the number of cylinders, or the material it’s made from the internal combustion engines used in automobiles all operate the same—they take in air and fuel, compress it, burn the mixture to make power, and then expel the spent gases. But even though the process of intake, compression, power and exhaust is the same for all engines, some engines do it more efficiently than others.
To maximize the performance of any engine the basic goal is to fill however many cylinders there are with a much air and fuel as possible. How well that is done is described as volumetric efficiency (VE), which is the difference between the theoretical amounts of air (or air and fuel) each cylinder can take in during the intake cycle compared to the actual amount taken in. With naturally aspirated engines, when the pistons drop on the intake stroke a vacuum is created and the higher atmospheric pressure outside the engine causes the cylinders to fill. That’s why engines run better at sea level where the atmospheric pressure is higher than at the top of a mountain pass where the pressure is lower. Obviously the way to enhance engine performance is to force more mixture into the cylinders and that can be easily done with a supercharger. Increasing pressure in the intake tract above atmospheric results in more mixture entering the cylinders and as a result VE goes up dramatically.
To power the 2015 ARP/STREET RODDER 1961 Ford Sunliner we chose a 427ci small-block from Ford Racing. As we explained in the May '15 issue of SR, these engines are based on blocks that Ford Performance engineers designed as replacements for the legendary BOSS 302 and 351 blocks. As we said then, "These new blocks are cast from diesel grade iron and designed with added material in key areas, which makes them far superior to any Ford OE block ever produced. In addition, by maintaining many of the dimensions and features from the original 289-351 blocks, these new Boss blocks fit just about any vehicle that used a Windsor-style engine."
As one of the goals of the Road Tour build is to include cutting-edge components we’ve elected to put our Boss 427 under pressure and add twin TorqStorm superchargers. TorqStorm is a division of Accelerated Tooling, a precision CNC manufacturing facility that provides services to a wide range of industries. Fortunately for hot rodders the owners of Accelerated Tooling, Chris Brooker and Scott Oshinski, both have a passion for cars and racing, which lead them to create Accelerated Racing Products to produce TorqStorm superchargers. These superchargers are the centrifugal type, which compresses the air inside the case with a spinning impeller, then discharges the pressurized air to carburetor or fuel injection system. By contrast a Roots (GMC-style) supercharger pumps the air/fuel mixture into the engine and pressurizes the intake manifold.
Similar in design to a turbocharger, centrifugal superchargers are belt driven by the crankshaft rather than being spun by exhaust gas. This not only simplifies installation, but it eliminates the low-speed lag turbo systems suffer from as they get up enough speed to produce boost.
When compared to other centrifugal superchargers TorqStorms are unique in a number of ways. Rather than a casting the housing and cover are machined from billet 6061 aluminum, the ceramic bearings are lubricated by an internal oil supply, which eliminates the need for plumbing into the engine’s circulatory system. Complete packages are available with a single supercharger; there are also dual supercharger kits as well as a solo system specifically designed for 1949-1953 Ford Flatheads and they’re all covered by a limited lifetime warranty.
For the ARP/STREET RODDER Ford we chose a complete kit to mount two TorqStorm superchargers on our Boss Ford. It included hoses, tubes, BOVs (blow-off valves) air filters, carb hat and all necessary brackets, pulleys, and hardware for a complete installation (although in our case Hollywood Hot Rods fabricated the inlet and outlet tubing, air cleaners, and fuel injection hat). Thanks to well thought out bracketry TorqStorm superchargers are easy to install and once in place dialing in the amount boost for the application is simple. The factory setting of 6-8 psi will bump up horsepower considerably, a bunch more horsepower is a pulley change away.
With the addition of the twin TorqStorms our engine was delivered to the team at the Westech Performance group for dyno testing. With 8.7 pounds of boost we saw 648 hp at 6,000. While that’s an impressive number what makes the wheels turn is torque. We love big, flat torque curves and we got one with 458 lb-ft at 3,100 rpm on the way to a peak of 593 lb-ft torque at 5,400. To prove the point that bigger numbers were easily attainable, the Westech guys swapped pulleys and upped the blowers’ boost to 12.9 pounds, which produced an impressive 721 hp at 6,000 rpm and 634 lb-ft of torque at 4,900 rpm. Again the torque was coming on strong early with 543 lb-ft at 3,600 and it wasn’t done yet. Another pulley swap provided 15 pounds of boost, which resulted in peaks of 790 hp and an astonishing 692 lb-ft. Given the numbers were coming on strong at that point Steve Brulé and the Westech crew were confident that 850 hp was a few rpm away but with the departure date for the Road Tour fast approaching time for more testing was non-existent. Thrilled with the potential to keep tour leader Jerry Dixey out of jail and to protect the car from any ham-fisted driver that might get behind the wheel the decision was made to dial the boost back a bit, but we can testify there’s still plenty of power on tap; besides we’re only a pulley swap away from more if we want it.
The TorqStorm superchargers delivered the power we were looking for, they’re known for reliability and they certainly look trick. We’re ready to turn our twin supercharged ARP/STREET RODDER Road Tour Ford loose for a full summer of cruising around the country. You can keep track of it and all the Road Tour happening in the pages of STREET RODDER at streetrodder.com or check it out firsthand and join any or all of our tours.
The 2015 ARP/STREET RODDER Road Tour 1961 Ford Sunliner packs some punch with a twin-supercharged 427 underhood. Like the rest of the car, the engine compartment was beautifully executed by Hollywood Hot Rods.
TorqStorm superchargers are available in in natural, black, or micro-polished finishes. Note the exclusive use of ARP fasteners. They were used throughout the car for appearance and strength.
These are TorqStorm supercharger cases; they are carved out of a solid block of aluminum on state-of-the-art CNC machines.
Like all the other components the input shaft and drive gear are built to exacting specifications, the tolerances these parts are held to would be close to impossible to achieve without contemporary manufacturing techniques.
The business end of the supercharger is the impeller. TorqStorms high-flow billet impeller is designed to produce low-rpm boost for improved driveability.
To produce boost the impeller spins much faster that crankshaft speed. At the bottom of the case is the drive gear spun by the crankshaft, the upper gear is connected to the impeller.
The twin superchargers are mounted to the engine with 3/4-inch CNC machined aluminum brackets that also accommodate the alternator and power steering pump. Note the adjusters on the idler pulleys that are used to establish belt tension.
These are the blow-off valves—they are vacuum controlled and serve a dual purpose. They only allow boost to occur above light throttle (when vacuum drops to a preset point) and they release excessive boost to prevent damage to the system when the throttle suddenly is closed on deceleration.
To provide clean air to the superchargers Hollywood Hot Rods fabricated mounts for dual K&N filters that fit behind the grille (this filter is for the right side of the car).
Speedway Motors supplied the Powermaster alternator that mounts via the TorqStorm bracket. It runs off a serpentine belt that also spins the water and power steering pumps.
The headers on our Boss 427 are metallic/ceramic coated Tri-Ys from Doug’s Headers. The ignition system and plug wires are from PerTronix.
To prevent premature wear and make sure our big Boss has a long life it was filled with AMSOIL Break-In Oil for the initial startup.
An AMSOIL oil filter was installed along with a black Lokar Midnight Series flexible dipstick.
Ready to roar on the Westech dyno. For testing purposes we used all the plumbing as supplied by TorqStorm.
Here one of the two blow-off valves is positioned in the tubes leading to the FAST fuel injection throttle body.
Don Armstrong’s U.S. Radiator supplied the radiator, shroud, and electric fan. Note the pressure cap in the custom tube fabricated by HHR.
Back from Westech’s dyno the TorqStorm blown Boss is ready for the 2015 Road Tour.
