The 2019 Ram 1500 remains a top contender in the full-size pickup segment, praised for its smooth ride, capable powertrains, and everyday usability. For owners seeking more power without a heavy investment in forced induction or internal engine work, the Flex Fuel Kit from Fueltech offers a compelling upgrade. Real-world testing has shown a 20 horsepower gain on the 5.7L HEMI V8 when running E85, and that increase translates into noticeable improvements in towing, passing, and overall drivability. This article explores how the kit works, the performance data behind the gains, the installation process, and what Ram owners can expect in daily use.

What Is a Flex Fuel Kit and How Does It Work?

A flex fuel kit allows a gasoline‑only engine to safely run on ethanol blends up to E85. The core components include an ethanol content sensor, a controller, and a recalibrated engine control unit (ECU) map. The Fueltech kit for the 2019 Ram 1500 is a plug‑and‑play solution that integrates with the existing fuel system and engine management. When the sensor detects a change in fuel composition, the ECU adjusts ignition timing, fuel injection duration, and boost (if applicable) to take advantage of ethanol’s higher octane rating—typically 100–105 RON for E85 compared to 87–93 for pump gasoline.

Higher octane allows the engine to run more aggressive timing without knock, which is the primary source of the power increase. Ethanol also has a higher latent heat of vaporization, cooling the intake charge and further reducing knock tendency. The Fueltech kit is tuned specifically for the 5.7L HEMI, ensuring safe air‑fuel ratios and avoiding lean conditions that could damage the engine. The result is a reliable power bump that the ECU can automatically dial back when the tank is filled with regular gasoline.

Performance Gains: More Than Just 20 Horsepower

The headline 20‑horsepower gain comes from dyno testing on a bone‑stock 2019 Ram 1500 with the 5.7L V8. Peak power jumped from 395 hp (at the flywheel) to 415 hp when running E85. But the real‑world benefits extend beyond the peak number. Torque increases by roughly 15–20 lb‑ft across the mid‑range, where drivers spend most of their time during daily commuting and towing. Throttle response sharpens noticeably—the truck feels less “lazy” off idle and pulls harder from 2,500 to 4,500 rpm.

Dyno Testing and Torque Improvements

Independent dyno runs posted on Ram enthusiast forums show consistent gains. One popular test from a certified shop recorded a 21.3 hp increase at the wheels on a Mustang dyno, which translates to roughly 25–26 hp at the crank after drivetrain losses are factored in. Torque peaked at 441 lb‑ft on E85 versus 422 lb‑ft on 93‑octane gasoline—a gain of 19 lb‑ft. The torque curve also plateaued earlier and stayed flatter, meaning the truck doesn’t have to downshift as aggressively during grades.

Real‑World Driving Experience

Owners report that the difference is most apparent when passing on two‑lane highways or merging onto fast‑moving freeways. The transmission holds gears longer before upshifting, and the engine feels more responsive to light throttle applications. Towing a 6,000‑pound trailer, the Ram 1500 with the flex fuel kit maintained speed on a 6% grade that previously required a downshift to third gear; with the kit, it held fourth gear at 3,500 rpm. That kind of real‑world improvement justifies the kit for many truck owners who use their vehicle for work or recreation.

Installation Overview

The Fueltech flex fuel kit is designed for straightforward installation, but it does require moderate mechanical skill and access to basic hand tools. The entire process typically takes one to two hours for someone comfortable working on modern fuel systems. A professional installation is recommended if you are not experienced with high‑pressure fuel lines or ECU programming, but many DIY owners complete the job in a driveway.

Key Steps

  • Disconnect the battery and relieve fuel system pressure by removing the fuel pump fuse and cranking the engine for a few seconds.
  • Locate the factory fuel line on the driver‑side frame rail. The flex fuel sensor is installed inline using supplied adapters—no cutting of factory lines is required on most 2019 Ram 1500 models.
  • Mount the sensor securely with the included bracket, ensuring it is positioned so that the electrical connector faces upward to avoid moisture ingress.
  • Route the sensor harness to the engine bay, connect it to the Fueltech controller, and plug the controller into the OBD‑II port. The controller intercepts the ECU signals and adjusts them based on ethanol content.
  • Reconnect the battery, prime the fuel system (turn key to RUN without starting for 2–3 seconds, repeat three times), then start the engine and check for leaks.
  • Perform a calibration drive of 10–15 miles to allow the ECU to adapt to the new parameters. No laptop tuning is necessary—the kit contains a pre‑loaded map for the Ram 1500.

Fueltech recommends using only the provided hardware and verifying that all connections are tight before the first start. A fuel pressure test adaptor can be added for long‑term monitoring, but it is not mandatory.

Fuel Economy and Ethanol Considerations

It is important to set realistic expectations about fuel economy. Ethanol contains about 30% less energy per gallon than gasoline, so miles per gallon will drop when running E85—typically by 15–25% depending on driving style and conditions. However, the power gain often allows the engine to operate at lower rpm for a given workload, partially offsetting the fuel consumption penalty. Many owners report only a 10–15% decrease in fuel economy when driving gently on E85, and the improved performance during towing can actually reduce total fuel consumption per mile under heavy load because the engine does not have to downshift as frequently.

Ethanol availability is another factor. In the United States, E85 is most common in the Midwest and parts of the Southeast. A quick search on the DOE Alternative Fueling Station Locator helps Ram owners identify nearby stations. For areas without E85, the kit simply reverts to factory gasoline tuning—no loss of performance compared to stock. The Flex Fuel Kit also works with E10 (10% ethanol, the standard pump blend) and E15 (15% ethanol), so owners can fuel up at any station without worry.

Owner Feedback

Long‑term reviews from Ram 1500 forums and Fueltech’s own customer database paint a positive picture. One owner on the 5thGenRams forum reported that after 15,000 miles with the kit, the engine had no unusual wear or check‑engine light events, and the 20‑hp gain remained consistent across multiple fuel fill‑ups. Another owner tows a 7,000‑pound travel trailer and noted that the transmission temperature stayed 10–15°F cooler on long grades compared to stock, likely because the engine does not have to work as hard to maintain speed.

Not all feedback is 100% glowing—some users in colder climates experienced slower starting in sub‑20°F weather when using E85, a known characteristic of ethanol blends. Fueltech provides a winter blend recommendation (E50 or lower) to mitigate this. Overall, satisfaction rates are high, with the majority of owners saying the power gain is worth the small trade‑off in fuel economy.

Conclusion

The Fueltech Flex Fuel Kit is a well‑engineered solution for 2019 Ram 1500 owners who want a legitimate power boost without major modifications. The 20‑horsepower gain is backed by real‑world dyno and owner data, and the seamless integration with the truck’s factory systems makes installation accessible to the average enthusiast. While fuel economy on E85 will be lower, the increase in torque, throttle response, and towing capability more than compensate. For those who live near E85 pumps and want a safe, reliable performance upgrade, this kit delivers genuine results.

For more technical details and ordering information, visit Fueltech’s official website. Additional owner experiences can be found on popular Ram forums such as 5thGenRams.com.