In The Build: Rear Turbo Mustang On Radials

And then of course, you’ve got to worry about the opinions of the New Balance sneaker-wearing Mustang Owners Clubs, and what they’ll say in hushed tones at car meets if you stray too far from the norm. Unless of course you’re the owner of this ballistic, radial-tyred Mustang in the build at B Custom Fabrications in Carrum Downs, VIC.

The build has been in a constant state of progress for several years, and the initial combo had a huge single turbo mounted in custom paneling behind the front seats, taking cold fresh air in through functional side scoops behind the doors.

“[The owner] just likes to do things differently!” laughs Brenton Graham from B Custom. “Everything we build here is a little bit different. We couldn’t fit the turbos in the engine bay and the Fastback had the side scoops anyway, so we thought ‘why not?” continues Brenton of the car’s original single rear-mount turbo guise.

After a session on the dyno it was determined that the single turbo set up was restricting power output as the boys aimed for their goal of over 2000hp at the hubs, so the single turbo was ditched in favour of twin Precision 86/85s.

As you can see, the twin turbo plumbing is a little more complicated. The intercooler piping is plumbed together with Motion Raceworks clamps and runs in to a water-to-air heat exchanger, with Turbosmart blow-off valves to vent excess boost and Turbosmart eGates mounted inline on the charge pipe to bleed off boost, instead of the conventional method of mounting the wastegate to the exhaust side.

“That set up is more common in the States, and the owner definitely has his finger on the pulse when it comes to what the racers are doing in the U.S,” continues Brenton. “Basically the turbos are spooling the entire time this way - we’ll see how it works.”

Under the bonnet, the small block Ford powerplant is governed by a suite of Fueltech engine management goodies, with the only indicator as to its pressurised power adders being the single intake tube snaking rearward through the firewall.

“We’re starting to get a fair bit going on back there between the water-to-air lines, the fuel lines, breather lines, trans lines and all the turbo plumbing,” admits Brenton of the maze of high-horsepower hardware living behind the seats. Amazingly, the turbos and ‘cooler are covered with trimmed paneling that incorporates a factory spare wheel. The Fastback can quickly be converted back to street form with the parachute removed and the 275 radials swapped out for factory Fastback wheels! “It’s a real wolf in sheep's clothing in street trim!” admits Brenton.