By the time you read this, our Project Evil 8.5 Ford Mustang will have already undergone its initial on-track testing and, barring any unforeseen issues — which we all know is always a possibility with a brand new racecar — prepared for its 8.5-inch tire racing debut with the NMCA WEST Series. As of this writing, we’re still wrapping up some of the final pieces to the puzzle, including wiring, plumbing, and many of the smaller bolt-on parts and pieces to finalize the long-awaited build.
Today, we’re going to focus on the plumbing side of things, and in specific, the assembly of the supercharger and intercooler piping that will deliver the boost from the Vortech Xi blower to the 427-inch small-block Chevrolet from Steve Morris Engines. We’ve teamed up with the crew at Burns Stainless in Costa Mesa, California to supply us with all of the components necessary to plumb our induction system.
The setup from Burns includes 10 feet of 16-gauge (1/16-inch or 0.0625-inch) straight tubing made of 6061 aluminum, a 90-degree, 16-gauge bend with an 11-inch straight section, a short 3.5-inch to 4-inch diameter transition, four aluminum flange assemblies, and four O-ringed and four non-O-ringed V-bands clamps to connect it all together.
To provide adequate airflow, we decided upon the use of 4-inch outer diameter tubing for the induction setup; however, given the 3.5-inch outlet on the Vortech Xi, the short transition, which you can see in the images, was needed to fan out into the larger pipe stretching to the intercooler and up to the throttle body. The whole process, of course, is one-off custom work, and the quality of the end product will depend on the fabrication and welding skills of whomever is plumbing the induction system on your own car.
Ultimately, the goal of any system like this is to keep the airflow as direct as possible, with as few bends and corners as you can get away with. Not every engine bay will afford nice, clean angles and routing, but as Burns Stainless’ Vince Roman shares, “you want it as straight and as short as you can make it.”
“The routing can make a difference,” Roman adds. “One of the things is that if you go further, it would be nice to go larger [in diameter] to reduce drag losses, but you’re kind of fighting that because you have limited space in the car to work with. But you want to be straight, short, and you certainly never want to decrease the tube size,” Roman explains.
Although numbers vary, there’s typically a couple pounds of boost lost in an intercooler application throughout the journey around the engine bay to the intercooler in the cockpit and forward to the intake manifold, thus the more you can adhere to Roman’s advice on routing, the less power you’re apt to lose.
…you want to be straight, short, and you certainly never want to decrease the tube size. Vince Roman, Burns Stainless
A 4-inch hole was cut in the firewall to route the tubing to the intercooler, while up top, a hole was cut large enough to fit the 4-inch pipe with the Wiggins clamp installed through it. We then fabricated aluminum plates to close up the gaps in the firewall, riveting them in and leaving less than 1/16-inch gap to make for a nice, clean look that allows minimal contaminants to enter the cockpit.
As you’ll notice, both of our Vortech Maxflow Race blow-off valves (P/N 8D204-111) are mounted in tandem in a straight section of tubing. This makes sense from a packaging standpoint as it’s essentially the roomiest place for them. However, there’s more than meets the eye, as straight sections of tubing, particularly close to the supercharger outlet, tend to experience fewer disruptions in airflow; bends can have pressure differences in the inner and outer curve of the pipe, for example.
“Blow-off valves blow off when you have transient pressure to keep the boost level at a specific point. There are a lot of things that can effect blow-off valves: many years ago IndyCar had a big deal where just by placing a spacer between the blowoff valve and the tube, it created a benefit that they had to outlaw. Funny things happen in bends, and you’ll have better pressure response in a straight piece of tubing as opposed to a bend,” Roman shares.
In what will be the final installment of this build, we’ll take a closer look at the collection of electronic systems that will help power, control, and collect data from Evil 8.5 when it hits the track. Keep it tuned here!