Tom Wilson
July 8, 2011
Photos By: Ford Motor Company

Name That Tune

The Boss 302 posed serious calibration challenges due to its unprecedented high rpm. Furthermore, the previous Coyote calibration in the '11 Mustang GT was of little help because changing the intake manifold, camming, even the oil viscosity, made the Boss 302 an entirely different challenge.

Jeff Seaman, who wrote all of the Coyote calibration, did most of the Boss 302 cal but was promoted to management in the middle of the job. Ford then put two superb senior calibrators on the job, Mark Sabuda and Gilbert Fournelle. They were occasionally assisted by Dev Saberwal, Ford Racing's calibrator, who has previous calibrating experience in everything from V-6 Mustangs to Ford's Jaguar Formula 1 team. The resulting Boss 302 calibration is entirely new and unique to the Boss, but is still housed in a Copperhead module.

If daily driving mode didn't pose anything particularly difficult to the calibrators, everything above 7,000 rpm did. "Everything you do at the top end is from scratch," Jeff noted. "Spark, variable cam timing, fuel, exhaust temperature--it's all unique." Some help came from Dev as he and his Ford Racing compatriots were the first to run Coyote-based engines above 7,000 rpm. "Being able to leverage Dev's experience on this was huge," says Jeff, and it marked the first-ever cooperative calibration effort between mainstream Ford and Ford Racing. This meant another first--Ford calibrators at the racetrack, taking data and running experiments on street cars under racing conditions. Jeff directly attributes the Boss 302's unique, larger radiator to track experience because that's where the Coyote radiator first proved inadequate thanks to the Boss' oil-to-water oil cooler.

But above all, it was plain old engine speed that made tuning the Boss 302 uniquely difficult. "There are a lot of concerns when you go run at high rpm" Jeff said. "Horsepower and rpm become an exponential cost item, and it's because the challenges you start running into are immense. It's not a simple one-off like, 'Hey you know what happens is that I run out of processing power.' No, it's things like my crank signal becomes much, much harder to see with a limited wheel that has only a finite number of teeth. It's my injector pulses start to overlap each other at high rpm. It's a ton of stuff. So it's not one item that trips you and says, 'I can't run at high rpm.' It's everything."

As Dev underlined it, "It's a systems issue, not really a processing power issue."

Today the Boss 302 runs seamlessly to 7,500 rpm, but you know Ford is relentlessly searching for more rpm capability. The issue is likely as much about cost as anything. High-end automakers such as BMW routinely offer 8,000-plus-rpm V-8s, and Dev has tuned F1 engines well into the rpm teens. But as Ford moves forward with the next Cobra Jet Mustang and beyond, the challenge will be how to electronically manage such engines and vehicles without breaking the budget. And that's because we all enjoy thrashing BMW M3s with a Mustang that costs $25,000 less.