In the May '05 issue of GMHTP, we began our installation of Vortech Engineering's centrifugal supercharger kit on our '04 GTO. As those of you who have read the last installment already know, the system delivers 7-8 psi of aftercooled boost via Vortech's V-2 compressor, and the kit is advertised as adding 131 horses at the crank. Those lucky readers also are aware that we are hoping to see over 400 at the rear wheels, having spun the dyno rollers with the power of 302.7 horses before beginning the install.
We got as far as bolting the blower itself on in the last issue. Now, follow along in the photos as we finish off the installation on our Phantom Black automatic test car by adding the blower ducting and aftercooler system. We promise that full results will follow in our next issue--but just to whet your appetite, we'll tell you right now that Vortech's advertised power increase was conservative, to say the least! Until next time, sweet dreams...
In order to prepare the power-steering cooler for its new location on the GTO, a large portion of its hard lines must be trimmed off. This is accomplished easily enough by use of a hacksaw. Enough material must be left for new Vortech-supplied rubber lines to clamp on to. After cutting is complete, it is a good idea to run a magnet along the outside of the lines to try and get as many metal shavings out as possible; shoot some WD-40 in there too and let it trickle out. | 
The power-steering cooler screws to the underside of the front crossmember using a couple of L-brackets, and then the cooler is reconnected to the power-steering system using some 3/8-inch rubber line. Since the newly cut hard cooler lines have no flare on the end of them, we suggest doubling up on the number of hose clamps used to attach the rubber hoses, just to be safe. The power-steering system must now be bled, a process that involves turning the wheel lock-to-lock numerous times while keeping an eye on the fluid in the reservoir (to look for bubbles as well as make sure the level stays high enough). | 
Vortech relies on air-to-water-to-air intercooling to drop the temperature of the intake charge going into the engine, and the heart of the system is its charge cooler. As compressed air is blown through the liquid-cooled heat exchanger inside this box, the air temperature can drop by over 100 degrees, freeing up as much as 100 hp, depending on the vehicle application and boost level. For the LS1 engine's 10.1:1 compression ratio, intercooling of some sort is also a very good idea to avoid any possibility of knock. |
Air entering the charge cooler will meet a heat exchanger with cool liquid flowing through it. Pressure loss (or flow restriction, whichever way you want to think about it) across this heat exchanger is minimal, only on the order of 0.25 psi. Some air-to-air intercooled systems can lose 3 or more psi before reaching the engine, often thanks to the extra plumbing needed to get compressed air to a front-mounted air-to-air intercooler. In addition, the "open" fin nature of Vortech's air-to-liquid heat exchanger causes less pressure loss per unit area compared to the more restrictive interior of an air-to-air heat exchanger. This is one of the reasons air-to-air intercoolers are often larger in size: to compensate for this effect and reduce their pressure loss. | 
Here, one end of the S-shaped, 2.75-inch-diameter aluminum discharge tube is attached to the outlet of the V-2 supercharger. The rubber coupler sleeves that Vortech supplies are top-notch heat-resistant silicone rubber in none other than Vortech Blue. The other end of this particular discharge tube connects to the charge cooler. | 
Here, the charge cooler is slipped onto the S-shaped discharge tube. You may be surprised to learn (as were we) that no bracketry is used to hold this cooler in place; instead, it simply rests upon the wiring harness and coils below it. Fortunately, Vortech supplies thick foam tape that adheres to the underside of the charge cooler for protection. |
In this photo, you can see just how tight the fit is between the charge cooler, its brass fittings, the dipstick, and the oil fill cap. It all works out just fine, though. The straight brass fitting is the inlet for cool liquid; the 90-degree fitting is the outlet for liquid that has been warmed by the compressed air passing through the charge cooler. | 
To complete the ducting for compressed air to travel through, an L-shaped, 3-inch discharge pipe is attached between the outlet of the charge cooler and a 90-degree silicone elbow that is affixed to the throttle body. One must be absolutely sure that the shorter leg of this duct is the one attached to the charge cooler or else things will not line up correctly. | 
At this point, it was nice to step back and take a look at just how far we had come with the kit installation, and we got really excited looking at that big honkin' blower system sitting atop the engine. You can also see here that with the stock strut tower brace reinstalled, a fraction of an inch of clearance is afforded between it and the top of the charge cooler; when adjusted correctly, it makes no contact whatsoever. Unfortunately, our BMR brace just wouldn't fit back on there. |
Vortech's bypass valve ensures that no more than 7-8 psi is seen at the throttle body, and it does this by rerouting compressed air back upstream of the supercharger as needed. This is especially important when one abruptly lifts off of the gas pedal (when shifting, for example), closing the throttle, and leaving compressed air upstream of the throttle body with no place to go. Instead of the air having to work its way backward through the supercharger--not good at all for the unit--the valve allows the air to bypass the V-2. | 
The bypass valve needs a vacuum signal to work properly, and it gets one by splicing a brass tee fitting into the brake-booster vacuum line, which is connected to the intake manifold, downstream of the throttle body. As such, when the bypass valve senses a pressure difference between the intake manifold and the supercharger ducting, the valve opens, thereby diverting air into the area upstream of the V-2. Often, the driver of a Vortech-blown car hears a hissing of air when letting off the throttle quickly because air travels backwards out of the air filter. | 
Warm liquid leaving the charge cooler enters a water reservoir that functions to increase the volume of liquid to work with in the system so that it can soak up more overall heat energy at any given time. Warm liquid enters the top and leaves the bottom where it then travels on to an electric water pump, and finally, to a heat exchanger mounted in front of the radiator. Made of lightweight plastic polymer, the reservoir is formed to fit in the space ahead of the GTO's radiator and behind the bumper. |
It's necessary at this point to attach a rubber junction to the brass fitting located at the top of the water reservoir, which will soon have an aluminum aftercooler water line slipped into it. The brass fittings here install into the plastic water cooler using open-end wrenches, but be careful not to overtighten them as the threads are, after all, plastic. Be sure to use some sealant on the threads. Note the nylon ratchet clamps Vortech gives you; they are a snap to install. | 
In order to make room for the water reservoir to sit in front of the passenger-side end of the radiator, a vestigial plastic bracket needs to be removed. Also, we discovered that the two power-steering cooler lines previously installed had to be squeezed as tightly to the left as possible, which necessitated stacking them vertically. In order to do this, some of the plastic radiator shroud (above them here) would have to be hacked away to make room. | 
To make matters worse, we hadn't left enough slack in the rubber power-steering cooler lines for them to be able to travel around the water reservoir and reach the power-steering cooler, as installed in the factory holes in the frame (marked with Xs). Thus, the power-steering cooler needed to be shifted toward the passenger side to compensate. Vortech's instructions didn't specify a length for the lines to be cut to. |