FuseTech
4JJ1 Stroker Shaft - 4.7mm - Fuse Tech
4JJ1 Stroker Shaft - 4.7mm - Fuse Tech
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Approx. 81% More Effective Stroke | Denso HP3 | Isuzu 4JJ1
Serious pump capacity for serious 4JJ1 builds.
The FuseTech 4JJ1 HP3 stroker shaft dramatically increases the effective stroke of the Denso HP3 pump, taking it from approximately 5.8mm to approximately 10.5mm. That is a gain of around 4.7mm, roughly an 81% increase in effective stroke.
High-output upgrade. This is not a mild stroker. Professional installation and ECU tuning are mandatory. A rail blank is recommended for sustained high rail pressure.
What the Numbers Mean
- Stock 4JJ1 HP3 effective stroke: approx. 5.8mm
- Stroker effective stroke: approx. 10.5mm
- Net increase: approx. 4.7mm
- Effective stroke increase: approx. 81%
Fuel delivery in an HP3 pump is directly related to plunger stroke. An increase of around 81% in effective stroke is a large increase in theoretical pump output, which makes this shaft suited to high-power applications where the factory pump becomes the limitation.
Key Features
- CNC machined precision: high-accuracy stroker profile for consistent pump output
- Large fuel volume increase: approx. 81% effective stroke increase over stock
- High power capability: supports aggressive injector and turbo combinations
- Built for load: manufactured from high-strength material for sustained rail pressure
- Cost-effective alternative: big pump output without moving to a different pump platform
Vehicle Fitment
- Isuzu D-MAX, 4JJ1
- Isuzu MU-X, 4JJ1
- Holden Colorado RC, 4JJ1
- Any 4JJ1 application running a Denso HP3 pump
What Is Included
- 1 x FuseTech 4JJ1 HP3 stroker shaft, CNC machined, brand new
Not included: installation instructions, pump seals or hardware. Professional fitting required.
Fitting Notes
- Professional installation strongly recommended. The HP3 requires precise assembly.
- ECU tuning required to safely control rail pressure and EGTs.
- Rail blank recommended for sustained high rail pressure: MCR rail blank.
- Suitable injectors and turbo system required for high-output builds.
- Contact us to confirm stock availability if timing is critical.
For off-road and competition use only. Fuel system modifications may affect compliance. Check local regulations before purchase.
Recommended Add-Ons
- MCR rail blank: deletes the factory pressure relief valve for sustained high rail pressure
- HP3 fuel pump seal kit: for the pump rebuild
Shipping and Payment
- Free express shipping Australia-wide
- Buy now, pay later: Afterpay, Humm, Klarna and Zip
- Diesel performance specialists, not general parts resellers
- Returns and warranty: see our refund policy
Frequently Asked Questions
Q: Do I need tuning after installing this stroker shaft?
A: Yes. Because of the large increase in pump output, ECU recalibration is mandatory to safely manage rail pressure, injection quantity and EGTs.
Q: How much power can this support?
A: With suitable injectors, turbo system, intercooling and tuning, this shaft supports very high-output 4JJ1 builds. Actual power capability depends on the rest of the fuel and air system.
Q: Is this a drop-in upgrade?
A: It is designed for the Denso HP3 pumps used on 4JJ1 engines. Because of the aggressive stroke increase, professional assembly and inspection are recommended.
Q: Is this a new component?
A: Yes. Each FuseTech stroker shaft is brand new, CNC machined and manufactured specifically for performance use.
Q: Why is a rail blank recommended?
A: The large increase in pump output can sustain very high rail pressures. A rail blank eliminates the factory pressure relief valve, letting you run higher sustained rail pressure without bleeding off fuel.
PUSH THE LIMITS OF YOUR 4JJ1
FuseTech HP3 stroker shaft, approx. 81% more effective stroke for high-output builds. Professional install and tuning mandatory. Free express shipping Australia-wide.
Disclaimer: Common Rail Cowboys is not affiliated with Isuzu Motors, General Motors Holden or Denso Corporation. FuseTech is a trademark of its respective owner. Stroke figures are approximate. Installation should be performed by a competent HP3 pump specialist and ECU tuning is mandatory. Fitment verification is the buyer's responsibility. Fuel system modifications may affect your vehicle warranty and compliance.
