In the case of the STS C5 kit, where most of the plumbing is routed inside the car's bodywork, the passive-cooling effect is less pronounced. The company's solution was to include with the system a large, front-mounted intercooler with a 29-inch-wide core. Squires says the unit cools the boosted air to within 10 degrees (F) of ambient temperature before it enters the engine, with a total pressure drop of around 3 psi from turbos to intake.
Fair enough, but we're Luddites at heart, and typically skeptical of purported technological breakthroughs until we've seen their merits demonstrated for ourselves. To find out how the STS C5 system worked in the real world, we contacted Greg Lovell at Anti-Venom Performance, a Seffner, Florida-based performance tuner specializing in LS-engined Corvettes and F-bodies. Lovell is an approved STS dealer and installer, and he was among the first in the United States to get his hands on a production C5 kit. Our test subject was an Electron Blue '02 drop-top, fully modified to Z06 specifications by owner David Thomas.
The primary components of the '99-'04 C5 kit (MSRP: $7,995) include twin T3/T04B Garrett turbos, a front-mount intercooler, 42-pound fuel injectors, DiabloSport custom tuning, a 38mm TiAL wastegate, and HPC-coated plumbing. (The '03 and '04 models require 60-pound injectors and a "booster"-style fuel pump for an additional $499.) The package is also available in "tuner" form (MSRP: $6,995)-minus injectors and programming-to fit all '97-'04 models.
You'll have to read on for the details, but suffice it to say that, aside from an unhealthy appetite for air bridges (more on that anon), the kit easily met STS's claims for both performance and packaging efficiency.
Somewhere, Alfred Buchi is smiling.
One of the more common criticisms of other STS kits is that they position the air filters too close to the ground, where water ingestion could conceivably be an issue. In the C5, the filters are mounted high up in the rear bodywork, just behind the taillights. A pair of Outerwears pre-filters (not shown) furnish an additional level of protection.
Editor's note: Given the necessarily conservative nature of the provided ECM tuning, Lovell elected to perform a slightly more aggressive (though still safe) dyno-based custom tune on the car in both low- and high-boost configurations. The output figures shown here reflect that custom tuning. Given the tuning variances that exist between individual vehicles, and the cost and complexity of the modifications involved, we strongly recommend that a vehicle-specific, dyno-based custom tune be performed in any forced-induction application where maximum output is desired.
 Thomas' system was optioned...  Thomas' system was optioned up with this TiAL blow-off valve ($300). In addition to keeping the turbos on the boil between shifts, the BOV emits a cacophony of pops and hisses guaranteed to earn you "mad street cred" with the slammed-Civic crowd. |  The C5 kit comes with this...  The C5 kit comes with this 48-tube front-mount intercooler, which features a 29-inch-wide core and purportedly cools the intake charge to within 10 degrees of ambient. STS claims that the overall pressure drop from turbos to engine is an impressively low 3 psi. |  Tucked away beneath the rear-bumper...  Tucked away beneath the rear-bumper cover, the Garrett turbochargers are all but invisible to the casual observer. Note the heat-retaining coating on the turbocharger-discharge pipe. |