ISR Performance Turbo Kit - Mazda Miata NB 1.8 - No Turbocharger Included

The ISR Performance Turbo Kit (Parts Only, no turbocharger) is the complete bolt-on turbocharger plumbing and hardware set for the 1.8L Mazda Miata NB (1999-2005), without the turbo itself included. Built around a Schedule 10 tubular manifold, chassis-specific intercooler, full polished aluminum piping, and AN-fitted oil and water lines. Designed for builders sourcing their own T25, T28, or compatible turbocharger.

What It Does

This is the same complete turbo plumbing kit as the IS-NB18TurboKit-T28, minus the turbocharger. Everything else you need to bolt the turbo system to a 1.8L NB Miata is in the box: manifold, intercooler, piping, downpipe, oil and water plumbing, and AFM-delete intake. The Schedule 10 tubular manifold resists cracking far better than cast or thin-wall tubular alternatives, which matters on a turbo Miata that'll see heat cycle abuse.

Turbo Compatibility

Designed for compact T25, T28, or GT-style turbochargers. The kit will require a bolt-on cover GT-style T28 turbocharger for a complete installation as-designed. Other T25 turbochargers such as the Garrett GT2871R can be used with simple modifications. Plan turbo selection accordingly during your build.

Critical Build Requirements

Aftermarket ECU required. The kit is designed for use with an aftermarket standalone or piggyback ECU running on a MAP sensor. The AFM is deleted by the included intake, so you cannot run this kit on a factory MAF-based ECU.

Hotpipe BOV flange sold separately. The included modular hotpipe accepts ISR, HKS, GReddy, or TiAL flanges, but the flange itself isn't in the box.

2.5 inch hole required for intercooler piping. Routing the intercooler piping through the chassis requires drilling a 2.5 inch hole.

Want the Turbo Included?

If you'd prefer a true single-purchase complete kit with a proven turbocharger already matched to it, ISR offers the same kit with the RST25/28 turbo included as part number IS-NB18TurboKit-T28.

Fitment

• 1999-2005 Mazda Miata NB (1.8L BP engine)

What's in the Box

• 1x Schedule 10 bottom-mount tubular turbo manifold
• 1x Intercooler and piping kit (polished aluminum, chassis-specific bracket)
• 1x Turbine O2 housing and downpipe
• 1x Complete oil and water turbo lines with 10AN aluminum weld bung for oil pan
• 1x AFM-delete intake with air filter

NOT included: Turbocharger

Product Details

Brand: ISR Performance

Part Number: IS-NB18TurboKit-Parts

Type: Turbo Kit Parts Only (no turbocharger)

Vehicle Fitment: 1999-2005 Mazda Miata NB

Engine: Mazda BP 1.8L

Turbo Required for Complete Install: Bolt-on cover GT-style T28, or Garrett GT2871R / similar T25 with simple modifications

Manifold: Schedule 10 tubular bottom-mount

Exhaust Construction: 304 stainless steel

Intercooler: Chassis-specific with mounting bracket, polished aluminum piping

ECU Requirement: Aftermarket ECU with MAP sensor (AFM delete)

BOV Flange: Sold separately (ISR, HKS, GReddy, or TiAL options)

Installation Note: 2.5 inch hole required for intercooler routing

Complete Kit Variant: IS-NB18TurboKit-T28 (turbo included)

Sold: Parts only, no turbocharger

Legality: Off-road and competition use only