“Bad Bob” is a 572 cubic inch big-block Chevrolet engine set up with a 10-71 supercharger, destined for use in a ’57 Chevrolet street car. Typically, a supercharger like this will use cable-driven throttle control, but that’s not the case in this applicaiton, says tuner Brian Macy of Horsepower Connection in Lake Havasu City, Arizona.
Macy is one of the more well-known EFI tuners in the country; additionally, he teachers users how to make their engine control systems perform optimally as one of the instructors of EFI University.
“The customer called me and didn’t know anything at all about fuel injection. Once we started talking about different options, he asked me about electronic drive-by-wire and I explained that nobody made an arrangement to use it with a blower. It turns out that he owns a machine shop, and he suggested getting the Chevrolet pedal and electric motor to see if we could make it work, and if it didn’t, we’d just put the cable-driven assembly back on,” Macy explains.
The customer fabricated a mount to put the factory drive-by-wire motor on the engine, and on the other side of the engine a linkage was installed to open and close the blower hat.
The engine is controlled using one of Holley‘s Dominator Engine Management Systems and presented no issues during the tuning session at Walt Austin Racing in Tacoma, Washington.
One of the expected challenges was tuning it properly, but Macy says the drive-by-wire controls in the Dominator made the job easy.
“I couldn’t believe how easy it was and how well it worked. One of the first tests I did when we put it on the dyno was to open the throttle wide open and close it to make sure it worked, then type in the computer one-percent throttle, and it would move it that one percent. For a street car with a blower hat on it, you move the throttle blade a tiny bit and you have enough air to where the engine just wants to take right off. In the Dominator system, you can tailor the curve and set it up how you want it to operate, to where the throttle pedal opens 20 percent but the blade only moves five percent. It can be set so that it feels more progressive like a regular car rather than a Funny Car,” he says.
As can be seen in the video below, the engine starts right up and rumbles away tame as a kitten until the throttle is cracked, and then the inner animal is released, with the blower whine an aural delight.