Big Blue24
Comp Diesel Sponsor
- Joined
- Jan 5, 2008
- Messages
- 6,320
The purpose of this thread is to discuss and display some of the performance modifications commonly found inside a 12 valve Cummins Injector. The injectors pictured made just over 700 HP and 1475 ft lbs with a maxed out 160 HP P7100 pump with modified 8mm delivery valves with a 028" shoulder, commonly referred to as DDP 024/042 valves.
This first picture displays a standard stock injector body on the left with edge filter in-tact, and the modified injector body on the right with edge filter removed.
The stock injector on the left has (1) feed passage down through the body that leads eventually to the nozzle. The modified injector on the right has (2) feed passages.
Looking in from the top side where the edge filter was removed, two sources of light can be seen on the dual feed passage injector body:
Moving down to the nozzle, we have a factory stock 145* 5x.009" VCO nozzle on the left and on the right is an EDM modified factory stock 145* VCO nozzle that has been enlarged to 5 x .0195", more than double the stock nozzle orifice size:
On the cold side of the nozzle where it attaches to the body, the stock nozzle is on the left and the modified nozzle is on the right with an added feed passage that lines up with the added feed passage in the modified injector body. This passage is larger than 060" in diameter, the edges appear to have marking from electro-discharge machining but I do not know for sure if EDM was used or if a special drill bit could be utilized for this modification.
And finally we have a stock injector needle on the left, and modified needle on the right. The modified needle has had 030" cut off the tip. This decreases needle "throttling" as it creates a larger feed path to the nozzle orifices. On a stock needle, at low lift the needle nearly blocks the nozzle orifices which meters or throttles injection somewhat. The modified needle clearly allows for a larger fuel delivery path.
And finally, the stoke limiting collar is the last modification found on these performance injectors. Pictured is the stock needle on the left and the modified needle on the right which has had 020" removed from the stroke limiting collar. This translates to 020" of added needle lift on the modified injector which allows the needle to throttle even less and adds a little duration to the injection event as the needle has more travel before the needle valve covers the nozzle orifices.
This first picture displays a standard stock injector body on the left with edge filter in-tact, and the modified injector body on the right with edge filter removed.
The stock injector on the left has (1) feed passage down through the body that leads eventually to the nozzle. The modified injector on the right has (2) feed passages.
Looking in from the top side where the edge filter was removed, two sources of light can be seen on the dual feed passage injector body:
Moving down to the nozzle, we have a factory stock 145* 5x.009" VCO nozzle on the left and on the right is an EDM modified factory stock 145* VCO nozzle that has been enlarged to 5 x .0195", more than double the stock nozzle orifice size:
On the cold side of the nozzle where it attaches to the body, the stock nozzle is on the left and the modified nozzle is on the right with an added feed passage that lines up with the added feed passage in the modified injector body. This passage is larger than 060" in diameter, the edges appear to have marking from electro-discharge machining but I do not know for sure if EDM was used or if a special drill bit could be utilized for this modification.
And finally we have a stock injector needle on the left, and modified needle on the right. The modified needle has had 030" cut off the tip. This decreases needle "throttling" as it creates a larger feed path to the nozzle orifices. On a stock needle, at low lift the needle nearly blocks the nozzle orifices which meters or throttles injection somewhat. The modified needle clearly allows for a larger fuel delivery path.
And finally, the stoke limiting collar is the last modification found on these performance injectors. Pictured is the stock needle on the left and the modified needle on the right which has had 020" removed from the stroke limiting collar. This translates to 020" of added needle lift on the modified injector which allows the needle to throttle even less and adds a little duration to the injection event as the needle has more travel before the needle valve covers the nozzle orifices.
op:
