Best Turbo Options After Deleting VGT on Cummins ISX

Turbochargers, VGT Replacement

Introduction

If you’ve recently removed the VGT (Variable Geometry Turbo) from your Cummins ISX, you’re probably wondering:
“What turbo should I replace it with?”

In this 2025 guide, we cover the best turbo options after deleting the VGT on a Cummins ISX, including models like the BorgWarner 171702 (S410SX), Holset HX60, and HX55, along with critical specs, performance gains, installation notes, and more.

Quick Tip: Fixed-geometry turbos improve reliability, reduce EGR failures, and offer consistent boost without electronic actuators.

Why Delete the VGT Turbo on a Cummins ISX?

The Cummins ISX VGT turbo is known for:

  • Electronic actuator failures

  • Sticking vanes

  • Increased exhaust backpressure

  • Higher EGR temps

  • Poor fuel economy

Switching to a fixed turbo eliminates these issues and simplifies the system—especially when paired with EGR and DPF deletes (for off-road/race use only).

Best Turbo Options After Deleting VGT on Cummins ISX

Below are the most recommended fixed geometry turbo models for a deleted Cummins ISX setup in 2025:

1. BorgWarner 171702 (S410SX)

  • Ideal For: High-performance ISX builds

  • Specs:

    • Compressor: 80mm inducer

    • Turbine A/R: 1.32

    • T6 flange, 360° thrust bearing

  • Performance: 550–700+ HP capable

  • Why Choose It: Exceptional flow, fast spool, durable under high load

  • Installation Note: Requires T6 manifold and custom oil feed/return

2. Holset HX60 (3592015 or 3592126)

  • Ideal For: Stock to moderate performance builds

  • Specs:

    • Compressor: 76mm

    • Turbine housing: 22cm or 25cm

  • Performance: Supports up to 600 HP

  • Why Choose It: Reliable, cost-effective, and widely available

  • Installation Note: May need 5″ downpipe and matched oil lines

3. BorgWarner S400SX3 (Model 171701 or 171698)

  • Ideal For: Balanced street and towing performance

  • Specs:

    • Compressor: 75–78mm

    • Turbine A/R: 1.25 or 1.32

  • Performance: 500–650 HP

  • Why Choose It: Good mid-range spool with strong top-end

  • Installation Note: Works well with 1.25 A/R housing for better drivability

4. Holset HX55 (3590044 or 3590045)

  • Ideal For: Budget-conscious fixed turbo replacement

  • Specs:

    • Compressor: 72–76mm

    • Turbine A/R: 22cm²

  • Performance: 475–575 HP

  • Why Choose It: Affordable, simple, and widely compatible

  • Installation Note: Best for fleets and rebuilds seeking reliability

5. BorgWarner 177148 (S475 Turbo)

  • Ideal For: Aggressive performance builds

  • Specs:

    • Compressor: 75mm billet wheel

    • Turbine A/R: 1.32

  • Performance: 600–750 HP

  • Why Choose It: High airflow with proven S400 platform reliability

  • Installation Note: Requires ECM tuning and T6 manifold

Turbo Comparison Chart

Turbo Model HP Range A/R Ratio Spool Time Price Range Notes
171702 (S410SX) 550–700+ 1.32 Fast $$$$ High flow, top-tier performance
HX60 (3592015) 500–600 22–25cm Medium $$$ Simple, reliable, drop-in options
171701 (S400SX3) 500–650 1.25–1.32 Quick $$$ Balanced boost and flow
HX55 (3590044) 475–575 22cm² Moderate $$ Budget-friendly and durable
177148 (S475) 600–750 1.32 Moderate $$$$ Max airflow, performance builds

What You’ll Need for a Turbo Conversion

  1. T6 Exhaust Manifold

  2. Custom Oil Feed and Drain Lines

  3. V-Band or Clamp Downpipe Adapter

  4. ECM Tuning to Disable VGT Function

  5. Boost Control Setup (Manual or ECM)

Choosing the Right Turbo: What to Consider

  • Power Goals: Know your HP target—don’t oversize unnecessarily.

  • Spool Time vs. Top-End: Smaller A/R spools quicker; larger A/R gives more top-end.

  • Application: Street, off-road, tow, or racing?

  • Budget: Aftermarket turbos range from $700 to $2500+

  • Tuning Support: Ensure ECM tuning matches turbo profile.

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