By now, you've probably heard about the Bosch P-pump, its actual name being the P7100, which is found on '94-'98 Dodges. These mechanical injection pumps are the kings of fuel production and used on drag racers and sled pullers, as well as street-driven trucks. What then, is a Sigma pump? Sigma was a company, like Bosch, that has been out of business for over 30 years. One of the injection pumps that Sigma made in France was for over-the-road semitrucks, and it has now found its way overseas decades later being used by some of the top pullers and drag racers in the country. Darren Morrison and Meacham Evins both run a Sigma in their drag race vehicles, and pulling trucks such as Curt Haisley's Off Constantly and Eric Stacey's Smokenya rely on Sigmas as well. To get the lowdown on this monster pump, we called Columbus Diesel Supply, one of the few companies that still has Sigma cores.
Columbus told us that the Sigmas use oversized injector lines and 16mm plungers instead of the 12mm versions you'd normally find in a Bosch P7100. As engine rpm increases, the window of time you must inject fuel to make peak power gets smaller and smaller. With a Sigma pump, it injects fuel at a much faster rate, which leads to a more efficient engine, and can take a 1,300hp pulling motor up to 1,500 hp. Although the Sigma can be adjusted to inject up to 1,600cc of fuel, most start their tuning at around 950cc. All this power doesn't come cheap, as Sigma pumps run about $9,600. If that's not enough, Columbus also makes a $15,000 "Billet" pump with 17mm plungers that can supply well over 2,000 hp worth of fuel.