Uncommon-Rail Injection: Look Behind Closed Doors, at S&S Diesel Motorsports

We had the chance to visit two of the S&S Diesel Motorsports sites in Michigan to see some common-rail injectors and pump magic for ourselves. At the northern Michigan facility, we were able to see some of the intricate microscopic work that goes into making injector nozzles deliver additional fuel with the EDM (Electrical Discharge Machining) process. Then we spent a day at Hudsonville, Michigan, to go over the nozzle honing, pump building and overall testing capabilities they have in house. While there are several techniques and methods that are proprietary, Greg Spoolstra walked us through the basics so that we could share what we learned with our readers.

Kyle Michael relies on S&S Diesel Motorsport fuel injectors driven by a quartet of Bosch CP3s to make tons of power with his common-rail Duramax-powered Super Stock Class pulling truck.

Kyle Michael relies on S&S Diesel Motorsport fuel injectors driven by a quartet of Bosch CP3s to make tons of power with his common-rail Duramax-powered Super Stock Class pulling truck.

 

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INJECTOR BUILDING

Starting with new complete injectors from top OEM manufacturers, Bosch and Siemens, the bodies are given proprietary internal treatments to optimize fuel flow and have control through the body into the nozzle. Injector nozzles feature a series of very small diameter holes that are specifically angled to form a spray pattern of fuel into the fuel bowl of the piston for combustion. To increase the flow through the nozzle, the S&S team uses the EDM process to precisely enlarge the holes in the nozzle using a high-voltage electrical current and an ultra-fine electrode. After the EDM process, both the inside and outside of the nozzles are inspected under magnification through the close-up lenses of a bore-scope and microscope to make sure the passages are accurately cut through the nozzle.

1. Linda Geiger operates the EDM equipment used to enlarge the openings in the injector nozzles in a precise and controlled method. Notice the small injector nozzle at the tip of the arrow compared to the size of the machining equipment.

1. Linda Geiger operates the EDM equipment used to enlarge the openings in the injector nozzles in a precise and controlled method. Notice the small injector nozzle at the tip of the arrow compared to the size of the machining equipment.

2. While the EDM operation is underway, dielectric liquid flows across the nozzle tip making the “spark” or actual removal of material from the nozzle barely visible.

2. While the EDM operation is underway, dielectric liquid flows across the nozzle tip making the “spark” or actual removal of material from the nozzle barely visible.

3. With the fluid flow shut off, you can see the sparks as material is removed from the nozzle.

3. With the fluid flow shut off, you can see the sparks as material is removed from the nozzle.

4. Ruth McLachlan inspects the inside of a nozzle with a borescope after the EDM machining is complete to make sure that the holes were properly cut.

4. Ruth McLachlan inspects the inside of a nozzle with a borescope after the EDM machining is complete to make sure that the holes were properly cut.

Just enlarging the holes in the nozzles is not enough for the crew at S&S—once the nozzles are EDM’d, they are honed under several tons of hydraulic pressure with proprietary abrasive media pressed through the nozzle orifices by an Abrasive Flow Machining process. Each set is machined to a flow tolerance of less than ± 0.5% tighter than even factory balance flow rates for optimum performance in your engine. This process further smooths the internal fuel passages in the nozzle while opening it up to the desired diameter according to the prescribed additional flow over stock. They offer injectors with enhanced flow ratings ranging from 30% over stock up to 200% over stock, as well as custom sized injectors for competition engine needs. Also, S&S helped engine builders integrate alternative injector bodies into competition engines when the fuel demand surpasses the physical limitations of factory based injectors.

5. Ruth also inspects the outside of the nozzle tip under a microscope to make sure that there are no problems with the machining.

5. Ruth also inspects the outside of the nozzle tip under a microscope to make sure that there are no problems with the machining.

S&S Diesel Motorsports

6/7. You can see the mass of machining and test equipment they have on hand to work their fuel system magic.

6/7. You can see the mass of machining and test equipment they have on hand to work their fuel system magic.

MODIFIED CP3S

The S&S team builds “stroker” CP3 pumps in 10mm, 12mm and 14mm configurations that deliver more fuel per rotation than a stock CP3 pump that only has about 8 millimeters of stroke. The long stroke pumps feature a new shaft with a larger diameter cam lobe and shorter pistons to deliver more fuel with each revolution of the shaft. They also offer conversion kits to upgrade new model GM trucks from the troublesome CP4 pump to a reliable CP3 while maintaining the necessary emissions related equipment.

TUNING

To wrap up a complete fuel system, the team at S&S Diesel Motorsports also sells and programs the Bosch Motorsports stand-alone ECUs that can be used to take full control of the engine electronics as well as auxiliary functions within a given race truck. They also offer the necessary high-range pressure sensors, high-range relief valves, custom high pressure lines, high volume fuel rails and all the other components needed for a complete competition level fuel system. DW

8. This fixture accepts up to 16 common-rail injector nozzles at a time for Abrasive Flow Machining.

8. This fixture accepts up to 16 common-rail injector nozzles at a time for Abrasive Flow Machining.

9. The fixture and nozzles are slid under the press where the abrasive media is forced through the nozzles under a great deal of pressure to enlarge and smooth the path of fuel flow through the nozzle.

9. The fixture and nozzles are slid under the press where the abrasive media is forced through the nozzles under a great deal of pressure to enlarge and smooth the path of fuel flow through the nozzle.

10. Greg Spoolstra operates the AFM machine to show us the process S&S nozzles go through.

10. Greg Spoolstra operates the AFM machine to show us the process S&S nozzles go through.

11. The abrasive media looks and feels like “Silly Putty” that you probably played with as a kid. When it is forced through the nozzle abrasives within, the media removes material from the internal walls of the nozzle as it flows past.

11. The abrasive media looks and feels like “Silly Putty” that you probably played with as a kid. When it is forced through the nozzle abrasives within, the media removes material from the internal walls of the nozzle as it flows past.

12. To simulate the part of the AFM process that we could not see, Spoolstra loaded a nozzle into a vice and then pushed the abrasive media through the nozzle by hand showing the trails of media from each of the nozzle’s five holes.

12. To simulate the part of the AFM process that we could not see, Spoolstra loaded a nozzle into a vice and then pushed the abrasive media through the nozzle by hand showing the trails of media from each of the nozzle’s five holes.

13. The S&S team has a large test machine to measure and verify injector flow and solenoid operation. Each injector within a set is matched to flow within ±0.5% which is a tighter tolerance than OEM standards.

13. The S&S team has a large test machine to measure and verify injector flow and solenoid operation. Each injector within a set is matched to flow within ±0.5% which is a tighter tolerance than OEM standards.

14. Here is a selection of some of the injector options offered by S&S Diesel Motorsport covering everything from stock type injectors up to monster injectors for custom applications. From left to right are injectors for an LB7, LBZ, LML (piezoelectric), 5.9L Cummins, 6.7L Cummins (next gen), 6.7L Scorpion, Case IH and LE (Large Engine with 2.5 to 3.0L per cylinder).

14. Here is a selection of some of the injector options offered by S&S Diesel Motorsport covering everything from stock type injectors up to monster injectors for custom applications. From left to right are injectors for an LB7, LBZ, LML (piezoelectric), 5.9L Cummins, 6.7L Cummins (next gen), 6.7L Scorpion, Case IH and LE (Large Engine with 2.5 to 3.0L per cylinder).

15. Looking at the inside of a CP3 pump, you can see the pump shaft (arrow on the right side) while the arrow to the left side of the shaft points to one of the cam followers (buckets) that ride between the polygon and the plungers in each of the three bores which pump the fuel to build the tremendous pressure needed for the common-rail fuel system to function properly.

15. Looking at the inside of a CP3 pump, you can see the pump shaft (arrow on the right side) while the arrow to the left side of the shaft points to one of the cam followers (buckets) that ride between the polygon and the plungers in each of the three bores which pump the fuel to build the tremendous pressure needed for the common-rail fuel system to function properly.

16. Here are three of the custom pump shafts S&S uses for its “Stroker” pumps. Notice that the base circle of the cam has a larger stroke as you move from the shaft on the left to the larger ones in the center and on the right. These are the 10mm, 12mm and 14mm shafts (from left to right) used in their high performance CP3 pumps.

16. Here are three of the custom pump shafts S&S uses for its “Stroker” pumps. Notice that the base circle of the cam has a larger stroke as you move from the shaft on the left to the larger ones in the center and on the right. These are the 10mm, 12mm and 14mm shafts (from left to right) used in their high performance CP3 pumps.

17. On the left is a stock CP3 cam bucket that is used in a standard stroke pump while the bucket on the right is the custom designed unit that S&S uses for their 12mm and 14mm pumps. They use a modified factory bucket for their 10mm pump.

17. On the left is a stock CP3 cam bucket that is used in a standard stroke pump while the bucket on the right is the custom designed unit that S&S uses for their 12mm and 14mm pumps. They use a modified factory bucket for their 10mm pump.

18. A stock CP4 is shown on the left with the S&S replacement CP3 unit shown on the right. The CP4 to CP3 upgrade kit for the Duramax engine will even work with the ninth injector for emissions compliance, while replacing the troublesome CP4 with the more reliable CP3.

18. A stock CP4 is shown on the left with the S&S replacement CP3 unit shown on the right. The CP4 to CP3 upgrade kit for the Duramax engine will even work with the ninth injector for emissions compliance, while replacing the troublesome CP4 with the more reliable CP3.

19. For big-power custom applications, the crew at S&S has larger pumps available in their arsenal, including: a huge CP9 that supports over 3,600-horsepower, and a two element CPN5 that is good for over 1,000-horsepower, along with the more familiar CP3 and CP4 pumps as seen from left to right.

19. For big-power custom applications, the crew at S&S has larger pumps available in their arsenal, including: a huge CP9 that supports over 3,600-horsepower, and a two element CPN5 that is good for over 1,000-horsepower, along with the more familiar CP3 and CP4 pumps as seen from left to right.

SOURCE:

S&S Diesel Motorsport

SNSDieselMotorsport.com