By Alfie Bilk:
Last fall, Pace Performance, the Boardman, Ohio, engine suppliers had plans to engage TorqStorm as their supercharger supplier. But first they required a comprehensive appraisal. The appraisal would take the form of dynamometer tests and to initiate the program, they dispatched a 383cid small-block Chevrolet to the premises of Lamar Walden Automotive in Doraville, Georgia.
The 383 was a crate engine from BluePrint Engines and its part number, BP38316CT1, indicated the unit was specifically designed for power-adders. In all likelihood there is no premium supercharger that has evolved more than this new contender and, despite being prescribed for stock and mildly tuned engines, its power-adding capacity would probably introduce an extra 200hp to the BluePrint 383. Nonetheless, Pace Performance was keen to find out how it would perform against an acclaimed blower from an established rival.
Over at Lamar Walden’s, the 383 with a 750cfm Demon Blow-through carburetor is attached to the dyno. A crankshaft drive pulley and spacer are attached to the harmonic damper. Then the ¾-inch-thick TorqStorm billet bracket is installed on the left cylinder head with three accompanying spacers and a backing plate. The supercharger is secured to its robust bracket by seven socket head bolts.
And then there’s the 8-rib serpentine belt, which is fitted and tensioned by a simple hand-adjusted idler. Thereafter, a small-bore hose is connected between the boost-reference port on the blow-off valve and the carburetor.
All that remains is to install the hat or bonnet on the carburetor and to connect it to the supercharger with the two large-bore discharge tubes supplied with the kit. Positioned between the discharge tubes is the inline blow-off valve, and tightening the 4 stainless steel hose clamps completes the arrangement.
In the dynamometer room, stood Rob Walden, who has been supervising and testing high-performance and competition engines and engine parts for 25 years. The tests would include, first, confirming the power output of the naturally aspirated BluePrint 383 engine. Second, they would assess the TorqStorm supercharger and, third, repeat the process with a Vortech unit.
Earlier, the BluePrint small-block sustained two days of comparison tests. The directive from Pace Performance also included exhaustive trials with supercharged EFI units—none of which, by the way, matched the performance of the blow-through carburetor.
It’s worth bearing in mind the fuel requirements for the boost condition as Walden reminded us: “Idle and cruise conditions don’t alter fuel consumption appreciably,” he says, “but boost conditions do. Also it’s important the spark plugs operate in the correct heat range.”
Commonly, supercharged engines run higher combustion temperatures than their naturally aspirated counterparts. Thus, spark plugs are usually one or two steps colder for the former to deter detonation, depending upon the amount of boost.
As you might expect, the dynamometer preparations for the tests were routine: crank-up the engine and allow it to reach normal operating temperatures—coolant around 180 degrees Fahrenheit, lubricating oil over 100 degrees and ignition timing checked, which had been set to 32 degree total.
After the first dyno pull, the spark plugs were removed for visual checking. For testers adept in spark plug reading, old habits are hard to break. Accurate spark plug readings indicate how the air-fuel mixture is burning in each cylinder, a handy skill to hold in reserve, especially when a problem arises and quick, empiric information is needed.
Inevitably, the dyno tests began by confirming that the 383 BluePrint small-block breathing at atmospheric pressure made 436hp and 460lb ft torque at 4300rpm. But when the TorqStorm was added it generated 627hp—an improvement of 191hp—with 566lb ft torque at 5800rpm and showing a flat curve on the graph. Though the Vortech generated a promising 620hp at 6,000rpm, its best torque delivery measured 546lb ft.
But the best part was the TorqStorm’s ability to generate 400lb ft torque at 2000rpm; its rival reached 400lb ft at 2500rpm. At 3000rpm the ‘Storm generated 484lb ft compared to the Vortech at 436 and as engine speeds increased the deficits slowly diminished to around 10lb ft at 5800rpm. Nonetheless, these were the auspicious symbols of an interesting comparison.
TorqStorm finishes their superchargers in natural alloy, black anodized or micro-polished and if someone were to ask me to name the single cleverest aspect of their new charger, I’d point not to the rigidity of its billet construction or the superiority of its ceramic bearings. I’d bypass the design mastery of its compressor wheel and its wide boost range, too, and point instead to its pricing: $2,800.