When converting a carbureted engine to electronic fuel injection (EFI), one of the most critical components you’ll need is a fuel pump that can handle the demands of modern injection systems. Unlike carburetors, which typically operate at 4-7 psi, EFI systems require **higher pressure**—usually between 40-70 psi, depending on the setup. For example, a common LS swap might need a pump capable of **58 psi at 255 liters per hour (LPH)** to maintain optimal air-fuel ratios. If you skimp here, you risk lean conditions, engine knock, or even catastrophic failure.
Let’s break it down with **data-driven examples**. Take the Walbro 255 LPH high-pressure fuel pump, a favorite among enthusiasts. It delivers **300 kPa (43.5 psi)** at 13.5 volts, making it ideal for engines up to **500 horsepower**. Compare that to a standard OEM pump for carbureted vehicles, which might struggle beyond **30 psi**. The difference in flow rates is stark: a stock mechanical pump averages **20-30 LPH**, while EFI-specific electric pumps like the Bosch 044 push **200+ LPH** under pressure. This isn’t just about power—**efficiency** matters too. A pump that matches your engine’s needs reduces strain on the electrical system and extends its **service life** (often **50,000+ miles** vs. 30,000 for mismatched units).
But how do you choose the right one? Start with **horsepower and fuel pressure requirements**. For a 350 HP street build, a 255 LPH pump (like the DeatschWerks DW300C) paired with a **return-style fuel system** works smoothly. If you’re pushing 700 HP in a track car, you might step up to a dual-pump setup or a brushless unit like the Radium Auto’s **500 LPH monster**. Don’t forget **compatibility**—some pumps won’t play nice with ethanol blends or aftermarket regulators. Brands like Aeromotive and Fuel Pump specialists emphasize ethanol-resistant materials in their designs, which can save you **$200+ in replacement costs** over two years if you run E85.
Real-world examples back this up. Take the 2021 SEMA Build of the Year, a ‘67 Camaro running a Holley Terminator EFI system. The builders opted for a Walbro 450 LPH pump to support a **700 HP LS3 engine**, citing its **98% duty cycle reliability** during dyno testing. Similarly, grassroots racers on forums like LS1Tech often recommend the Bosch 044 for its **durability in high-vibration environments**—something cheap knockoffs can’t match.
Budget is another factor. A quality EFI fuel pump runs **$150-$400**, but cutting corners risks leaving you stranded. One Reddit user shared a cautionary tale: a $90 eBay special failed after **1,200 miles**, costing them a tow and a weekend event. Meanwhile, a properly sized pump from a trusted brand might add **0.5-1% to your total project cost** while slashing long-term headaches.
So, what’s the verdict? Match your pump’s **flow rate**, **pressure rating**, and **material quality** to your engine’s needs. If you’re unsure, consult a build sheet or reach out to specialists—many retailers offer free support to avoid compatibility pitfalls. After all, even a 10% mismatch in fuel delivery can mean the difference between a purring engine and a pricey paperweight.