2013 Ford Mustang Boss 302 - Blown Boss
JBA Speed develops a 50-state legal Vortech kit for the high-winding Boss 302 and a hot rod is born
Perhaps we should first note that with stock suspension, brakes, and tires, the blown Boss rode and handled like a Boss 302, which is to say perfect. The Boss is the Mustang we've been waiting for the last 30 years, and each time we're able to pedal one, our enthusiasm for the precision and easy speed is rekindled.
Adding the Vortech to the mix is a good thing in that the centrifugal blower is perfectly matched to the stock Boss 302 power curve. Unlike positive displacement superchargers that require removing the Boss's distinctive and personality-making short runner intake manifold, the Vortech works with the stock intake. This translates into stock-like power off idle and through the lower portion of the tach, then a building rush of extra thrust the higher the engine is revved. Redline remains stock, but the urge from 4,500 rpm to over 7,000 rpm is magnitudes greater.
In practice, with the JBA demonstrator and its 3.73 rear gears, this means First gear was far too short to get usable blower power down before the tires went up in smoke; Second gave exciting acceleration until the last 1,200 rpm when the tires broke loose every time. A short shift into Third works best, where the force-fed Boss gets into some serious acceleration into the felony-fast zone.
For puttering around town, the JBA Boss is and feels stock, and your mom might wonder why you spent 10 large for a blower. But in daily driving, the blower isn't a factor, and even a quick shot of full-throttle typically isn't enough to bring the supercharger into play given slumbering cruising rpm. The Vortech supercharger is also notably lighter than its positive displacement competition. JBA corner weighted their Boss, finding the blower added under 65 lbs to the front axle—not enough to feel at the strip or in the corners in all but back-to-back testing.
In other words, the car feels showroom until you leg it out a little, and then it rages. Blower assist is rarely used on tight winding roads, but if the corners are spaced a little wide it can provide a thrilling rush. It would be a scream at an open track or the drags where you can keep the engine on the boil all the time. And we should say, it's not like a nitrous car where it's all or nothing, but the big joy is still at the top of the tach.
All said, the blower Boss easily passed our bottom line test; it's the sort of car that makes you look for excuses to go drive it. Part of that appeal is its sound. JBA chose to open the blocking plates in the Boss side exhaust, resulting in a snarling, crackling deceleration and a real call of the wild bellow when in the boost. It's too loud for daily use in the 'burbs, but everybody loves it for the first 15 minutes, and you could always keep the plates in the sound tubes for a near-stock sound. The blower itself is all but inaudible.
Also lending hot rod tone is a mad-cat hiss from the blower's bypass valve. This comes into play under deceleration when the still-spinning supercharger's output is vented to avoid excessive charge air heating. This is sound engineering (to play an atrocious pun), but not what impresses your wife with its industrial white noise. That said, the big racing bypass valve is proper for this hard-charging installation and sounds off only when the engine is already loud with rpm and exhaust noise, so it isn't overbearing by itself.
But, add the racy rpm, raucous exhaust, and by-pass whoosh together and Ford's Boss sophisticate turns into a hot rod, just the way Texans like Bittle like it. If you prefer your speed a little quieter, simply keeping the exhaust plates in place would make the difference. That, and rolling up the windows, definitely distances the mechanicals in these modern, heavily sound-proofed Mustangs.
We uncovered no glitches in J's demonstrator. Everything started, stopped, and ran as advertised. There was a slight plateau, or step, in the acceleration at part-throttle, but only sometimes and Tucker and Vortech were still fine tuning the combination when we drove it, so it will be long gone on production kits.
If you want to be long-gone with one of these kits, JBA has what will cure your urge. Given Vortech's high efficiency and time-tested durability, we think it would be a great ride for the dedicated performance fan, track drivers, or those simply wanting that little bit more of the Boss 302 feel.
On the Dyno
Boss 302 Naturally Aspirated
JBA Boss 302 Supercharged
Data provided by JBA using their in-house DynoJet chassis dyno. Baseline naturally-aspirated data obtained using standard key (non-Track Key).