Honda/Acura B-Series ProAM EFR Twin Scroll Turbo Kit


Honda/Acura B-Series ProAM EFR Twin Scroll Turbo Kit

Honda/Acura B-Series EFR T4 External-WG Turbo Kit

The competitive racer’s turbo kit of choice, the Full-Race ProAM has been making and breaking records since its introduction. Available in twin scroll T4 configuration, Full-Race engineers designed the twin scroll ProAM top mount manifold to deliver power levels normally seen from enormous turbochargers, but with drastically improved throttle/boost response, significant power/torque gains and reduced lag. Optimal runner length and ideal cylinder pairing increase turbocharger efficiency to levels previously unseen. Full-Race ProAM gains 25-40whp over ProStreet for the same size turbo. Fits EG, EK, DC with B16, B18 and B20 engines.  We recommend 1.05 A/R for most applications, but 1.45 a/r is available for competitive drag racing

T4 EFR Turbo Options: EFR 7163EFR 7064EFR 7670EFR 8374EFR 9174EFR 9180

*Also available with turbos from Garrett, Precision, and Xona Rotor

Key Design Features:

  • The merge collector creates a turbulent free area for the exhaust gasses to enter the turbine housing in even pulses at high velocities
  • Robotic TIG welding for ultimate strength and longevity
  • Flange surfaces machined flat ensuring a perfect seal
  • Developed as the focal point of Full Race's civic, this design underwent extensive testing as the subject of a master’s engineering thesis for an Arizona State professor
  • Made In The USA

Dual 38

Dual 44

Accurate boost control is enabled by the twin wastegates, allowing for huge amounts of wastegated exhaust flow – and good traction. This manifold is used and endorsed by virtually all of the top Outlaw and SFWD drag race vehicles on the race circuit today. Spool gains of 800-1000 can be realized, resulting in midrange gains of 100-200+ whp/wtq and tremendous top end gains. For the ultimate in B-Series turbocharging technology, look no further.

Full-Race Honda/Acura B-Series T4 Twin Scroll Turbo Kit Includes:

  • Full-Race B-Series Twin Scroll Turbo Manifold
  • Full-Race B-Series Twin Scroll 3″ to 4″ Downpipe
  • Full-Race B-Series Intercooler
  • Full-Race B-Series Charge Piping
  • Full-Race B-Series Kit Box


Full-Race B-Series Twin Scroll 4″ Downpipe


Full-Race B-Series Intercooler

Full-Race B-Series Charge Piping

Includes Couplers and Clamps

Full-Race Hardware, Fittings & Lines


Optional TiAL MVS or MVR Wastegates


Optional TiAL Q Blow Off Valve


About Twin Scroll:

Twin Scroll turbo system design addresses many of the shortcomings of single scroll turbo systems by separating those cylinders whose exhaust gas pulses interfere with each other. Similar in concept to pairing cylinders on race headers for N/A engines, twin scroll design pairs cylinders to one side of the turbine inlet so that the kinetic energy from the exhaust gases is recovered more efficiently by the turbine. For example, if a four-cylinder engine’s firing sequence is 1-3-4-2, cylinder 1 is ending its expansion stroke and opening its exhaust valves while cylinder 2 still has its exhaust valves open (while in its overlap period, where both the intake and exhaust valves are partially open at the same time). In a single scroll AKA undivided manifold, the exhaust gas pressure pulse from cylinder 1 is therefore going to interfere with cylinder 2’s ability to expel its exhaust gases, rather than delivering it undisturbed to the turbo’s turbine the way a twin scroll system allows.

The result of the superior scavenging effect from a twin scroll design is better pressure distribution in the exhaust ports and more efficient delivery of exhaust gas energy to the turbocharger’s turbine. This in turn allows greater valve overlap, resulting in an improved quality and quantity of the air charge entering each cylinder. In fact, with more valve overlap, the scavenging effect of the exhaust flow can literally draw more air in on the intake side while drawing out the last of the low-pressure exhaust gases, helping pack each cylinder with a denser and purer air charge. As we all know, a denser and purer air charge means stronger combustion and more power… but the benefits of twin scroll design don’t end there. With its greater volumetric efficiency and stronger scavenging effect, higher ignition delay can be used, which helps keep peak combustion temperature in the cylinders down. Since cooler cylinder temperatures and lower exhaust gas temperatures allows for a leaner air/fuel ratio, twin scroll turbo design has been shown to increase turbine efficiency by 7-8 percent (faster spool, quicker response) and result in fuel efficiency improvements as high as 5 percent. It is wise to size the turbine housing A/R larger than the single scroll turbine A/R typically used!

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Product NameHonda/Acura B-Series ProAM EFR Twin Scroll Turbo Kit
BrandFull Race
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