Stanadyne RGX 12mm High-Pressure Fuel Pump for GM LTx

RGX Pump + Eight Injectors Package

See package savings in cart. Add one Stanadyne RGX 12mm high-pressure fuel pump and eight Stanadyne 7.45mm high-flow injectors to the same cart. The package discount applies automatically; no code is needed.

Both products in the required quantities must remain in the cart to receive the offer. Limit one package discount per order. Additional units are charged at their regular listed prices. Taxes and shipping are calculated separately. This offer cannot be combined with other product or order discounts.

Package fitment: GM Gen V LT1 and LT4 applications, plus trucks with L8T, L86, L87, L83 or L84 engines only when the cylinder heads accept the larger 7.45 mm injector nozzle. This injector package is not for LT2 or LT6 applications. Confirm the actual cylinder-head injector bore/nozzle size before ordering. Professional installation and calibration are required.

Purpose-Built Direct-Injection Fueling for Serious GM LTx Power

The Stanadyne RGX is not a modified production pump. It is a purpose-built 12.0 mm high-pressure direct-injection pump engineered for builders, tuners and race teams pushing GM Gen V LTx combinations beyond the practical limits of OE-style fuel-pump capacity.

Stanadyne validated the RGX through more than 500 hours of durability testing on both 7.85 mm and 8.2 mm fuel-lobe configurations. The redesigned lower assembly, upgraded spring system and optimized internal discharge passages are built to maintain stable, efficient fuel delivery under high lift, high engine speed and wide-open-throttle operation.

RGX Performance Highlights

• Purpose-built 12.0 mm plunger high-pressure pump
• DLC-coated bore and piston
• 443 liters per hour at 7,000 engine rpm with a 7.85 mm fuel lobe
• Recommended fuel-lobe lift: 7.85 mm
• Maximum tested fuel-lobe lift: 8.2 mm
• Engine-speed capability up to 8,000 rpm
• Compatible with production LT1 and LT4 pump lobes and properly configured aftermarket high-lift lobes
• Improved inlet orientation for LT2 packaging
• Optimized discharge passages for increased high-rpm and WOT efficiency
• 100% tested for performance and functionality
• Compatible with gasoline, E10 through E85 and M15
• Designed for naturally aspirated, supercharged and turbocharged combinations

Pressure and Supply Requirements

• Recommended operating pressure: up to 250 bar / 3,600 psi
• Low-side fuel pressure of at least 70 psi is required to achieve maximum output
• The complete system must be sized correctly, including low-side pump capacity, injectors, commanded rail pressure and calibration

Critical Installation Requirements

This pump is not a simple bolt-on-and-go installation. Correct installed height and plunger preload must be measured and verified before final installation.

• Required installed plunger preload: 1.20-1.80 mm / .047-.070 inch
• Recommended lobe lift: 7.85 mm; maximum tested lift: 8.2 mm
• Do not use a lash cap. Stanadyne specifically prohibits lash-cap installation because immediate pump and/or engine failure may occur.
• If preload is too high, additional .012-inch / 0.3 mm gaskets are used to reduce preload
• If preload is too low, the pump flange may require professional machining to achieve the required range
• Apply blue threadlocker and torque the pump bolts evenly to 25 Nm / 18 ft-lb
• Do not allow the plunger to bottom out

Wrong preload can cause pump failure, loss of plunger-to-lifter contact at high rpm or internal piston contact. Installation measurements must be submitted through Stanadyne's RGX installation-validation portal to register the pump and support any future warranty consideration.

Open Stanadyne RGX Installation Validation and Product Registration

Technical Documents

Open RGX Technical Details in a New Tab

Open RGX Preload Requirements in a New Tab

Professional Installation Strongly Recommended

Fuel-system capability, injector capacity, camshaft fuel-lobe geometry, rail-pressure strategy and tuning must be evaluated as a complete package. SMG Speed Shop and North Texas High Performance can supply and install the supporting low-side system, injectors and calibration components required for a properly engineered GM LTx fuel system.