What Does The Fass Fuel System Do To A 6.7L Cummins & How Much Does It Cost?

If you know diesel engines, you're already well acquainted with the name Cummins. The Indiana-based manufacturer has been a major player in the diesel realm for more than a century now and, at present, is building its punchy power plants at facilities located throughout the United States and the United Kingdom. The company has come a long way since it first began producing its wares within a converted cereal mill. Its current lineup of diesel-powered offerings is as revered for its durability as any brand in the game. They tend to rank among the more powerful as well, with gear heads the world over constantly searching for ways to get more out of the Cummins diesel engine powering their trucks. 

If you're among that lot, you may have already had a look at FASS Diesel Fuel Systems, as the homegrown Missouri company has become one of several outfits to devise products specifically geared toward bolstering the performance of a Cummins engine, including products that may boost the performance of Cummins' torquey 6.7-liter power plant. But to understand what FASS systems do, we should examine the name itself. 

FASS is an acronym for Fuel Air Separation System, which signifies the systems are high-end filtration units designed to reduce contaminants in your fuel. Per the company's site, they increase performance in part by removing 99% of water from your fuel and filtering out debris, as well as increasing fuel lubricity. According to FASS, its fuel systems can increase the life of a diesel engine's fuel injection components. 

Given Cummins' long-standing deal with Dodge and its spun-off Ram Trucks line, it's safe to assume your 6.7L diesel engine is powering a Ram, and that means you've got plenty of options to choose from in the FASS online store. The exact system you choose may be influenced by the current output of your 6.7L Cummins, though the company claims you can install any system from their catalog on a stock truck, so the system you buy depends on what you want your engine to do.

FASS also notes that you should consider any future engine upgrades you might be planning, as they may affect the product's performance and that of your Cummins 6.7L. It currently offers systems at varying costs for Cummins-powered Ram trucks, though they are listed as on sale at the time of this writing, so the prices may change. 

The purchase prices also do not include installation fees, which may dramatically increase the cost. A No-Drop unit (which replaces the vehicle's entire current fuel system) FASS pumping 100 gallons per hour for a stock engine pushing 600hp will set you back $799, while a No-Drop system pumping 290 GPH for a 1200hp to 1500hp engine is listed for $929. The lowest-priced, easiest-to-install FASS system, designed for a Ram made between 2019 and 2024, will be a Drop-In unit retaining the OEM fuel pump, which can be had for just $479.