SpeedFactory Forward Facing B-Series Outlaw Turbo Manifold

SpeedFactory Racing Forward Facing B-Series Outlaw Turbo Manifold - Part #SF-04-051

This is the manifold on the B-series cars that hold the records. The SpeedFactory Racing Forward Facing B-Series Outlaw Turbo Manifold hangs a large T4 turbo out in front of the engine on long merge collectors, and it's built for one job: a high-revving, big-turbo B-series drag engine where the only thing that matters is how much exhaust energy reaches the turbine and how fast. If you're building a street car, stop here and look at SpeedFactory's bottom mount instead.

What It Is and Why It Works

A forward facing manifold puts the turbine where a radiator normally lives. That buys you runner length. SpeedFactory's ultra-long merge collectors let each pulse settle before it meets the turbine, so exhaust enters the housing in even, high-velocity pulses instead of colliding at a short collector. On a 9,000 rpm B18 or B20 with a big T4 frame turbo, that's the difference between a turbo that lights at the hit and one that lights halfway down the track. SpeedFactory has set and broken records on its own B-series cars with this exact manifold.

Construction is 1.5 inch schedule 40 polished stainless, TIG welded and back purged so the inside of the weld doesn't sugar and crack after heat cycling. Head, turbine, and wastegate flanges are cut from half inch 1018 steel plate and machined flat. You choose a T4 open or T4 divided turbine flange; the divided version pairs the cylinders correctly for a twin scroll housing. Wastegate flange is a single 60 mm Tial, a single 60 mm Turbosmart PowerGate, or twin 44/46 mm V-bands. All of them are sized to bleed off a lot of exhaust, which is what keeps boost under control and the tires hooked on a car this far into the power.

Specs

Available Options

Fitment

Bolts to any B-series cylinder head. Chassis fitment depends on how much of the front end you are willing to cut. Plan on a tucked or relocated radiator, radiator support trimming, and custom intercooler piping on every chassis. This is a drag race manifold and is not a street part.

What to Know Before You Buy

Every one of these is built to order. Figure 6 to 10 weeks before it ships, and plan the build around that. Match the turbine flange to the housing on the turbo you already own and the wastegate flange to the gate you already own. An adapter plate on a manifold this hot is where leaks and cracks start. If you're running twin scroll, buy the divided manifold; if you're running an open T4 housing, the open version saves you money.

The forward facing layout means the turbo lives where the radiator was. Budget for a tucked radiator, trimming the radiator support around the frame rail, an intercooler with custom end tanks or a backdoor core with pipes that clear the turbo, and a traction bar that clears the downpipe and dump tubes. Don't heat wrap it. SpeedFactory's warranty covers welding defects only and it is void on a wrapped manifold or one run with an undersized downpipe or dump tube, because trapped heat cracks stainless. If any of that sounds like more than you signed up for, SpeedFactory's bottom mount or top mount B-series manifolds are the right call.