Honda/Acura K-Series Twin Scroll EFR T4 EWG Turbo Manifold
Full-Race’s Twin scroll EFR T4 EWG turbo manifold for the K-series engines fits every Honda K series chassis from K-swapped CRX’s, Civics and Integras, to EP3 civics and RSX’s. Designed for maximum power output for built engines and trans, this manifold utilizes Full-Race’s unique runner configuration to seperate exhaust pulses for unmatched throttle/boost response. This produces an exhilarating experience for street strip builds or fast spooling road race time attack setups. Our K-series manifolds are compatible with RHD and LHD vehicles, and twin scroll EWG EFR turbos with 1.05 A/R for a built street/road race car or a high-boost drag race application. We believe the K-series twinscroll to be the ultimate high power turbo manifold for the K-series RSX and EP Civic or swapped EG / EK / DC.
- Fits almost every Honda K series chassis combination from 1988 to 2005: K-swapped CRX’s, EF/EG/EK/EM1 Civics, DC Integras, EP3 civics and RSX’s with K20 and K24 engines
- RHD and LHD compatible
- twin scroll External WG spools early with maximum high boost power
Honda/Acura K-Series Twin Scroll EWG EFR Features:
- Based around 4-2-1 low angle merge collector for efficient flow into the turbocharger
- CAD designed
- Robotic TIG welding ensures superior strength and long service life
- 100% Handmade in the USA from high grade thickwall stainless steel
- Requires dual external wastegates and dumptubes
- Sealing surfaces machined flat ensuring a leak free seal
Optional 2000 Degree Titanium Coating:
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!