- #Cummins big cam 350 pump turn up how to
- #Cummins big cam 350 pump turn up install
- #Cummins big cam 350 pump turn up mods
#Cummins big cam 350 pump turn up install
It’s important to note that the best way to install the Mack rack plug is with the pump off the engine. While not a “free” mod, this one will only set you back $10 to $15.
While 2 mm might not sound like much, the Mack rack plug adds roughly 70 cc’s worth of fuel to the mix and can be good for anywhere between 10 to 35 additional horsepower depending on your pump’s overall combination (specific P7100 model, delivery valves, fuel plate setup and injectors). The popular “Mack rack plug” shown above increases rack travel from 19 mm (stock) to 21 mm. While adjusting the star wheel increases rack travel, the factory rack plug will only allow so much fuel into the plungers and barrels. It’s up to you to find the right balance here. Go too little, and you won’t see the power gains you’re after. If you go too far, heavy smoke will result. The star wheel is accessed via the top of the AFC housing, and adjustments should be made in very small increments. The fuel rack controls the amount of fuel that’s allowed to enter the pump’s plungers and barrels. Turning the Star WheelĪs for the aforementioned star wheel adjustment, turning it toward the passenger side of the truck opens the fuel rack more. And when combined with a star wheel adjustment (located within the AFC housing), as much as 200 lb-ft of torque can be added, along with a peak horsepower increase of 50 to 60 horsepower. By sliding the AFC housing forward (toward the front of the pump) and backing out the pre-boost screw (on the backside of the AFC housing), fueling can be brought in at a much lower rpm, the governor linkage is altered and the rack is adjusted forward. In addition to dictating when the governor arm hits the AFC arm, the AFC is in charge of controlling the pump’s fuel rate at low boost. Air Fuel ControlĪt the back of the P7100, you’ll find the air fuel control (AFC) assembly. Think of the P-pump as a mini inline-six cylinder engine bolted to the side of your inline-six cylinder engine. This marvel of mechanical engineering is fairly complex. If you wanted your truck to make 500 horsepower (a big number back then), it wasn’t going to happen with what the competition was offering (the HEUI-fired 7.3L Power Stroke or GM’s indirect injection 6.5L, respectively).Ĭontrary to what some would have you believe, the P7100’s robustness, performance and reliability don't make it simple.
Bosch P7100īack in the mid ‘90s, long before common-rail injection had debuted and horsepower wasn’t quite as easy to come by, this was the four-barrel carburetor of the diesel world. Then we’ll explore the internal upgrades that can take this pump from mild to wild.
#Cummins big cam 350 pump turn up mods
We’ll begin with the mods that won’t cost you a dime, but that can add more than 100 hp. In this article we’ll explore all the components within the P7100 that can be modified to improve its performance. It represents easy horsepower for those handy with a wrench, huge horsepower for anyone willing to spend some money and - like the Cummins engine it was bolted to - million-mile durability. The Bosch P7100 is arguably the single most recognizable symbol of diesel performance. That’s right, the injection pump hanging off the side of the renowned and revered ’94-’98 5.9L Cummins is more important than the engine itself.
Instead, we’re highlighting the biggest reason for this engine’s celebrity: the Bosch P7100. But, this isn’t another holy grail piece where we worship the almighty 12-valve. common-rail debate, reminding us where diesel performance stemmed from or (it never fails) kick off a brand loyalty brawl. The very mention of this legendary mill seems to reinvigorate the never-ending mechanical vs.
#Cummins big cam 350 pump turn up how to
How to Get More Power From Your P-Pump CumminsĪny time we write about the 12-valve 5.9L Cummins, we can always count on plenty of feedback from readers.