4N GT-EFR B58 turbo kit

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  • Regular price $6,399.00

The 4N-B58 GT EFR turbo kit. This kit fits Gen1 B58 and I confirmed the hot parts fit Gen2 G series with an updated head flange. Gen2 release coming soon.


4N-B58 EFR GT Turbo kit information below!



The B58 manifold shares the same overall design as our S55 kits. The manifold is a twin scroll design and we are continuing to use 321 stainless sch10 material. This is much lighter than thick wall sch40 construction. 1.25 sch10 has a larger 1.42in ID proven to flow up to 2,000HP on inline 6 applications. Our twin scroll design has better time to boost and is designed with only long radius bends that are as close to equal length as possible.




This kit is designed to use the twin scroll IWG EFR lineup. Boost is controlled by the factory electronic wastegate actuator. This offers oem + level boost control, more reliability, and less weight for road racing or daily driving use. The 8474, 9274, and 9280 are utilized with a 600-1000whp range.




The downpipe for the 4N-B58 EFR kit is 3.5 and can be ordered in a 4in version as well. We designed a factory connection adapter so you can use your stock exhaust if desired and simply remove the adapter if you want to add a race pipe or have a custom higher flowing mid pipe built. I do recommend going to a 3.5 midpipe for better flow. 4N B58 F series midpipe option will be available soon!

•charge pipe/ intake

Our charge pipe design has no tight radius elbows coming off of the compressor housing that limit flow. The charge pipe attaches to the compressor cover with a quick release clamp allowing easy removal. The intake uses a large radius 4in OD pipe and a high flow filter that won’t collapse or cause a restriction.


•Heat management/ thermal expansion

Our B58 kit comes with a heat shield designed for track use. Road racing for 30-45min with high EGTs and high track temps can wreak havoc on turbo kit hot parts and can really test a kits design. Thermal expansion is factored in and our kits handle 1,800F+ on the track and expand/ contract properly during heat cycles. This is why they don’t fatigue crack in these conditions.