Many performance enthusiasts believe the only way to make a centrifugal supercharger work is to install it on a fuel-injected engine. When it comes to carburetor-fed machines, the theory is forced induction is simply not tuneable when it's blown through a standard four-barrel fuel meter. While it's a fact that electronic fuel injection does have benefits when it comes to maintaining a more constant air/fuel ratio, there's no question that an equal amount of power can be tuned through a carb when you know what you're doing.
With companies like Vortech Engineering investing time, money and effort to produce an effective "blow-through" supercharger, the interest in throwing one of these power-adders onto classic machinery is growing by leaps and bounds. One of the more recent introductions is their setup for First-Gen Camaros (which also adapts to '64-72 Chevelles, '62-72 Novas, and '55-57 Tri-Fives). And since our own Classical Resurrection '68 F-body was available, the gurus at Vortech jumped at the chance to use it as a guinea pig.
With the popularity of their blow-through systems at an all-time high, they recognized the need for a Camaro unit. The basic kit began as one of their universal carbureted packages. Most enthusiasts can afford this kit and with a little creativity, basic mechanical aptitude, and some patience, it can be installed in a weekend.
As most readers know, the staff here at SUPER CHEVY prides itself on being ready to tackle almost anything the industry throws at us. And, as many may recall, the Classical Resurrection has been the recipient of many "firsts" throughout its maturing process. So what's one more experimental installation, we thought. Why not help out the guys at Vortech and see if we can finesse their F-body package?
To say that this kit is a bolt-on is an understatement. Aside from the well-crafted blower (and in our case, a polished one!), the setup includes a nice billet bracket arrangement (replete with belt idler pulley) that mounts the huffer up high on the left (driver's) cylinder head. It also comes with a crank pulley that includes the requisite ribbed-belt section and a V-belt arrangement for running other items such as an alternator and power steering pump. Of course there's the neat polished aluminum box where the carb resides, and all the necessary ducting that helps route the air into it.
What you don't get in the kit is the "other" half of the components that will make it work. We're talking about the intake manifold, carburetor and fuel system. The selection of parts we used, although approved by Vortech, are not the only ones that will work with this system. Our combination included an Edelbrock Victor Jr. intake (and aluminum water pump), a Demon 750cfm double-pumper carb and a way-cool Product Engineering fuel pump and boost-reference regulator. Other supporting components were a neat 6BTM boost retard ignition box plus a corresponding small-cap billet distributor and companion 8.5mm plug wires from MSD, March billet water pump pulley, Lokar throttle and kickdown cable assemblies, Granatelli sheetmetal valve covers, and a trick adjustable polished thermostat housing from Billet Specialties. Of course, there were also miles of cool plumbing (hose and fittings) from Russell to make it all come together.
The supercharger offered in this universal kit is Vortech's "standard" model. This blower can be tuned to put out more than 10 pounds of boost, though on street applications it is not recommended to run more than 6 pounds, which is enough to produce up to 140 hp, providing the tune-up is dialed-in properly (that means correct air/fuel ratio, timing, etc.).
The way that Vortech's system works is that it forces the boost into the aluminum box where the carb is completely sealed within. Once it enters the "box," the carb is essentially pressurized and with increased throttle position, the boost level rises and, voila, more power is produced. While it sounds simple enough, it's really a little more complicated than that, as the engine needs more fuel in proportion to the rise in boost. This is where the Product Engineering fuel pump and regulator play a major role.
At 310 gph, the Product Engineering street/strip bypass fuel pump is more than enough to feed this system. Coupled with their four-port billet aluminum boost-reference fuel regulator, controlling the fuel is a simple matter of setting the pressure at idle to between 6 to 7 pounds and attaching the vacuum line to the carb box. What happens is that the regulator senses the increase in boost and essentially ups the fuel pressure at a rate of 1 pound of pressure to 1 pound of boost. This is how the engine is prevented from running too lean. Theoretically, with this linear increase in fuel pressure, the air/fuel mixture stays ideal. Of course, part of the tuning is making sure that the carb jetting is on target, as well.
The other factor in getting the supercharger system to work up to par, is making sure that the ignition timing is within an acceptable range. It's widely known that when you add boost, you must take away timing. Therefore, initial setup requires that you back off of the optimum timing for a normally aspirated engine in the neighborhood of 4 to 6 degrees. So, if you'd normally place the advance at 34 total degrees, you'd back it down to 28 to 30 with the blower in place. The nice thing about MSD's 6BTM is that it includes a boost retard control that can be adjusted while you're driving the car from 0 degrees per pound of boost to 3 degrees per pound. This allows the engine to be run right up on the threshold of detonation for maximum power without allowing knocking to occur. Example if you set the dial at 2 degrees, that means for every one pound of boost the ignition box will remove 2 degrees of timing. So at max boost, or six pounds the ignition box will take out a total of 12 degrees of timing. In most cases saving the engine from detonating itself to death. Though this may sound like we're adding a bunch of exotic pieces to a high-dollar engine that already produces a ton of power, it isn't. For this project our base engine was a bone-stock, never been run before 300-horse, 350-inch crate engine. A perfect starting point for this supercharger setup, for sure.
The installation of the supercharger was fairly simple. Although Vortech didn't have a specific kit for a First-Gen Camaro, we picked up the ball, with the help of Jim Sleeper and Bob Vrbancic. Included in this phase was creating the fuel system, adapting brackets to mount all of the other front-of-the-engine components, and finally, getting it to run.
While the project has taken roughly a year to come to fruition, we feel that the finished system has the best combination of parts. And, although our initial trip to the dyno only netted us 80 hp (to the rear wheels), we can only say that was because we ran out of time and weren't able to make any jet changes. We also learned a few lessons about plumbing the boost reference regulator and getting the correct fuel pressure. With these lessons we'll move on to getting the car to run. Then we're planning to take it up to Vortech where they can add some of their expert tuning and show us how much power this First-Gen creation can really make. Stay tuned!