KJ Jonesx
February 21, 2014
CXRacing designed its Fox twin-turbo system for ’86-’93 ’Stangs, which were equipped with airboxes and thus had natural openings in the passenger-side inner fenders to serve as locations where discharge tubes can be routed from the turbo, and also from the intercooler to the throttle body. With Greg’s coupe being an ’84 that originally had a carburetor, the appropriate cuts were warranted. Determining exactly where to clearance the panel is a trial-and-error process in which Rene mounts, clocks, makes reference marks, and remounts the turbo several times to ensure correct positioning all around.
The CXRacing twin-turbo system includes a pair of 38mm wastegates with 8-psi springs, and dumps that bleed off excess boost.
After a minor amount of cutting and rewelding, Rene created a pipe that clears the pan. Going forward, the transmission type must be specified when ordering a twin-turbo system from CXRacing.
While the system’s downpipes are 2.5 inches, CXRacing offers 3-inch downpipe flanges and V-band clamps as options.
In addition to the ’86-’93 year range, it’s important to also note that the CX turbo kit was developed for Mustangs with five-speed, manual transmissions. With Greg’s Pony sporting a Performance Automatic Super Comp AODE transmission in its trans tunnel, we quickly discovered that the 3-inch exhaust tubing on the driver side does not clear an automatic tranny’s fluid pan.
Ascension bores a passage in the driver-side framerail for that turbo’s discharge pipe, which, like its passenger-side counterpart’s tube, also is plumbed into the intercooler. While CX’s twins system is designed for ’Stangs that still have full accessories (air conditioning, power steering, and so on), a Pony’s battery must be relocated to the trunk or hatch area.
Ascension mock-fits CXRacing’s bolt-in air-to-air intercooler at the front of our test ’Stang. The bar-and-plate ‘cooler features a 3.5-inch core, measures 27x12.5x3.5 inches, and is specifically designed with two 2.5-inch inlets for discharged air from the Fox system’s twin GT35 turbos. All of the aluminum tubing is mandrel-bent, including the large 3-inch discharge pipe from the intercooler to the throttle body. All clamps, silicone hoses, and a blow-off valve also are included with the intercooler.
Wastegates receive boost references from small tubes mounted at the end of the turbos’ discharge outlet.
Once the turbos are mounted, Rene connects 2.5-inch, stainless-steel downpipes to the turbine housings on each unit.
Due to the intercooler’s size, the coupe’s front bumper cover requires a slight amount of trimming for correct clearance. After installing the bumper and marking cut areas, Ascension uses a simple pair of snips to remove material from the cover.
A blow-off (bypass) valve is mounted in the intercooler’s 3-inch discharge tube to release pressurized air when the throttle is closed during shifts (with a manual transmission) and deceleration.
With this system, the mass-air sensor actually is supposed to sit farther down the intercooler discharge tube (inside the inner fender area), before the bypass valve. We elected to swap the sensor’s and valve’s positions for easier access to the mass air, which did require a bit of custom tubing fab by Rene.
Turbochargers emit incredible amounts of heat throughout the engine compartment. CX provides plenty of protective/insulative sheath material for preventing spark plug wires from completely melting.
Here’s a look at the newly twin-turbocharged engine, almost ready to fire. The next stop for Greg’s Pony is the exhaust shop, as a custom mid-pipe (with V-band flanges) must be made for mating the turbo kit’s exhaust to a ’Stang’s tailpipes.