Increased stroke
More plunger travel moves more fuel with every pump revolution.
Customer test data
Bench tested
After seeing conflicting claims about the kit, one customer built a 10.6 mm pump from a used eBay LBZ core nearing 20 years old and paid Oregon Fuel Injection to test it on a Bosch EPS945.
Customer-built LBZ-based 10.6 mm
283.1 L/h
3,500 RPM
Donor pump:used eBay LBZ corenearing 20 years oldmileage/history unknown
+40.3%vs. Bosch LBZ stock target
6.9 L/h belowthe advertised 290 L/h benchmark
Flow comparison
How 283.1 L/h compares
The customer-built 10.6 mm test result alongside published Exergy and S&S flow data.
Compare by RPM
Stock Pump≈57.8 L/h
Exergy 10mm Stroker≈72.3 L/h
S&S 10mm Stroker≈79.0 L/h
DIY 10.6 mm Stroker Kit77.4 L/h
≈ Digitized from published chart
Stock Pump≈118.9 L/h
Exergy 10mm Stroker≈146.5 L/h
S&S 10mm Stroker≈159.1 L/h
DIY 10.6 mm Stroker Kit168.8 L/h
≈ Digitized from published chart
Stock Pump≈188.0 L/h
Exergy 10mm Stroker≈257.2 L/h
S&S 10mm Stroker≈275.7 L/h
DIY 10.6 mm Stroker Kit283.1 L/h
≈ Digitized from published chart
Our 10.6 mm values are direct Bosch EPS945 measurements. Stock, Exergy, and S&S values are digitized from the linked manufacturer charts. Test conditions differ, so this is not a same-bench comparison.
View all values
| Pump RPM | Stock Pump | Exergy 10mm Stroker | S&S 10mm Stroker | DIY 10.6 mm Stroker Kit |
|---|---|---|---|---|
| 1,000 | 57.8 L/h | 72.3 L/h | 79.0 L/h | 77.4 L/h |
| 2,000 | 118.9 L/h | 146.5 L/h | 159.1 L/h | 168.8 L/h |
| 3,500 | 188.0 L/h | 257.2 L/h | 275.7 L/h | 283.1 L/h |
Stock Pump. Stock reference trace published with Exergy's comparison data. 1,000 RPM: 57.8 liters per hour; 1,500 RPM: 88.5 liters per hour; 2,000 RPM: 118.9 liters per hour; 2,500 RPM: 148.9 liters per hour; 3,000 RPM: 178.4 liters per hour; 3,500 RPM: 188.0 liters per hour
Exergy 10mm Stroker. Published Exergy CP3.3 comparison data. 1,000 RPM: 72.3 liters per hour; 1,500 RPM: 109.3 liters per hour; 2,000 RPM: 146.5 liters per hour; 2,500 RPM: 184.4 liters per hour; 3,000 RPM: 221.5 liters per hour; 3,500 RPM: 257.2 liters per hour
S&S 10mm Stroker. Cummins CP3-CU-10 published comparison data. 1,000 RPM: 79.0 liters per hour; 1,500 RPM: 118.6 liters per hour; 2,000 RPM: 159.1 liters per hour; 2,500 RPM: 198.1 liters per hour; 3,000 RPM: 237.2 liters per hour; 3,500 RPM: 275.7 liters per hour
DIY 10.6 mm Stroker Kit. One customer-built LBZ-based 10.6 mm Duramax pump; separate Bosch test-program stages. 1,000 RPM: 77.4 liters per hour; 2,000 RPM: 168.8 liters per hour; 3,500 RPM: 283.1 liters per hour
How it works
More stroke. More flow.
The kit increases pump displacement and includes the supporting hardware needed to make the added stroke work properly.
Increased displacement
The added stroke increases the amount of fuel the pump can deliver.
Supporting hardware
Each kit includes the cascade valve upgrade, with matched LDSA tappets included on 10.6 mm kits.
Machined in-house
Every stroker shaft is machined in-house at Motorsport Diesel in Tennessee.
In the kit
What’s included
Choose your configuration to see exactly what your kit includes. Configure your kit.
- Motorsport Diesel stroker shaft
- Cascade valve modification kit
- Large Diameter Surface Area tappet set
- Step-by-step instructions and installation videos
- CP3 Shaft Press Tool
- CP3 Tappet Tool
Fitment
Match the kit to your CP3
| Application | Available strokes |
|---|---|
| 2003–2007 5.9 Cummins | 9.8 mm |
| 2007.5–2025 6.7 Cummins · 19 mm cascade overflow valve | 9.5 mm / 10.6 mm |
| 2007.5–2025 6.7 Cummins · 16 mm cascade overflow valve | 9.5 mm / 10.6 mm |
| 2001–2006 Duramax LB7/LLY · 16 mm cascade overflow valve | 9.5 mm |
| 2006–2010 Duramax LBZ/LMM · 19 mm cascade overflow valve | 9.5 mm / 10.6 mm |
Fitment notes: 6.7 Cummins does not fit CP3 pumps retrofitted from CP4 applications. LB7/LLY fitment excludes Bosch 0 445 020 005 and the 8 mm supply-pump drive used on some 2001–2002 LB7 trucks.
Installation overview
Designed for DIY installation
With the right tools and a clean work area, the included step-by-step videos guide you through the complete installation.
- Clean assembly area
- Common shop tools
- CP3 shaft press tool for all applications except 5.9 Cummins
- Press to remove the old shaft and install the new one for all applications except 5.9 Cummins
- CP3 tappet tool for 10.6mm configurations
Donor condition
Start with a healthy CP3
Your donor CP3 should be in good working condition before conversion. If its condition is uncertain, have it inspected or tested before installation.
Technical FAQ
Common questions
Does the DIY stroker kit actually increase CP3 flow?
Yes. A customer-built LBZ-based 10.6 mm pump measured 283.1 L/h at 3,500 RPM on a Bosch EPS945, compared with the Bosch LBZ stock target of 201.8 L/h. See the test results and flow comparison.
How much flow can the 10.6 mm kit make?
The 10.6 mm configuration is rated at 290+ L/h at 3,500 RPM. The customer-tested build measured 283.1 L/h using a used eBay LBZ core nearing 20 years old with unknown mileage/history. Results can vary with donor condition and assembly.
Do I need a modified FCA/FPR or other pump upgrades?
A modified FCA/FPR/MPROP is not required. Reuse a compatible stock unit if it is in good condition; the kit includes the parts needed for the selected configuration.
Can I use my existing or a used CP3?
Yes, if it is compatible and in good working condition. The kit does not repair existing donor wear. The 283.1 L/h test used a used eBay LBZ core nearing 20 years old; if your pump's condition is uncertain, have it tested before installation.
What if the pump does not rotate freely after installing the shaft?
Do not force it. Manufacturing variation can occasionally cause shaft-to-tappet interference. Follow the documented clearance procedure and use the relevant machined tappets and CP3 tappet tool where required.
What tools do I need for installation?
You need a clean assembly area and common shop tools. All applications except 5.9 Cummins also require a CP3 shaft press tool and a press to remove the old shaft and install the new one. The 10.6 mm configuration also requires a CP3 tappet tool. See the installation overview.
Should I have the pump tested after I build it?
Testing is not mandatory for every build, but it can verify pump operation and output before installation, especially with a used or unknown-history donor. Have your CP3 tested.
How do I know which kit fits my CP3?
Use the fitment table and Identify your pump guide. The 16 mm and 19 mm cascade overflow valve distinction helps identify the correct pump option.
Before ordering
DIY product terms
DIY installation means the installer is responsible for proper fitment, assembly, cleanliness, measurements, and clearance checks. Review the full terms before purchase.
Verified customer reviews
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