T4 BorgWarner EFR Twin Scroll Turbo Kit Builder | MX5 NA/NB

Description

Configure a complete BorgWarner EFR twin scroll turbo system for the Mazda MX5 and Miata NA/NB, built around the Kraken cast NiResist D5S Type 2 twin scroll manifold.

Pick what you need, skip what you don’t. Every component in the builder is designed, tested and validated as a system. No guesswork, no parts that almost fit.

Manifold, Downpipe & Exhaust

The foundation is the T4 twin scroll manifold cast from NiResist D5S Type 2. True 1-4 / 2-3 scroll pairing with 38mm ID runners, internally gated, AC compatible. Flows 600hp+.

Choose your configuration:

• Manifold and 3″ downpipe
• Manifold, 3″ downpipe and full exhaust
• Manifold, 3″ downpipe and full exhaust with twin exit

The 3″ downpipe connects via V-band with a tight radius bend to clear the chassis. Made from 304L stainless steel, TIG welded, pie-cut bends back purged. The exhaust is hand-made 304L stainless, straight-through with V-band connections throughout. Muffler, resonator and optional 200 cell metallic cat made in Sweden by Simons Exhaust Systems.

Turbo (Optional)

Add a BorgWarner EFR turbo matched to your power goals:

• EFR 6258 (T4 IWG)
• EFR 6758 (T4 IWG)

All units are new and ready to bolt to the twin scroll manifold.

Intercooler

Front-mount intercooler kit with turbo-specific piping for the MX5 NA/NB. TIG-welded aluminium pipes with bead-rolled lips, 4-ply reinforced silicone couplers, and welded BOV and throttle body flanges. No adapters or clamps.

BoostProducts tube-and-fin cores matched to your power level:

• 550x140x65mm – up to 300hp (AC compatible)
• 550x180x65mm – up to 350hp (AC compatible)
• 550x230x65mm – up to 500hp (not AC compatible)

Simple Intake

Filter and intake piping sized for the EFR compressor inlet.

Lines & Fittings

Oil feed, oil drain and coolant lines for the EFR turbo. Everything needed to plumb the turbo into your engine.

Injectors

Upgraded fuel injectors matched to your target power level.

How the Builder Works

Start at the top and work through each step. The configurator filters out incompatible options as you go, so you only see parts that work with what you’ve already selected. Use the live chat if you need help with your configuration.

Specifications

• Manifold material: NiResist D5S Type 2
• Runner ID: 38mm
• Manifold weight: 6.4kg
• Scroll pairing: 1-4 / 2-3
• Downpipe/exhaust material: 304L stainless steel
• Intercooler piping: TIG-welded aluminium
• Turbo compatibility: BorgWarner EFR 6258, 6758, 7163 (T4 IWG)
• Platform: MX5 / Miata NA and NB (1989-2005)
• AC compatible: Yes (manifold and select intercooler cores)

Additional information