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Fuel Pump Flow Test - Power Hungry
Going inside modern Mustang fuel systems on Kenne Bells' fuel flow bench
To see how various pumps performed at stock and elevated voltage levels, we hit the bench. Our photos detail Kenne Bell's Fuel Flow Dyno 3000, as the fuel bench is dubbed, but the reason that compelled the KB team to build the bench is worth reinforcing. Until the '11 Mustang GT (and other late-model Detroit hot rods) came along, Kenne Bell relied on in-car testing or an older, less sophisticated fuel bench they had built many years ago. However, the new fuel systems were unknown and complex enough that in-car testing could no longer show sufficient detail of what was going on in the fuel system.
The goal was to build a bench that would support the entire fuel system out of the car, allowing the measurement of flows and pressures at many points in the system. This allows easy testing of the fuel system, both as a whole and as individual parts. Kenne Bell says the fuel bench has proven invaluable as an engineering development tool, and also supplies sales leverage because it gives them the data to prove how its equipment works.
If electrically boosting the stock fuel pump is the real-world solution for the vast majority of Coyotes, there are still plenty of pre-Coyote and hero-class power applications where a larger fuel pump is the way to go. And seeing how Kenne Bell has already tested nearly every pump available on its new fuel bench, we're presenting some of the data on four popular fuel pump options to put numbers to their performance. What follows is data showing the pumps at both the stock 13.5 volts and augmented to 21 volts by way of a Boost-A-Pump.
First of the popular options is the stock Coyote pump. Here's a detailed look at it, flowing by itself on the fuel bench at four voltages. We're showing the 12-volt readings to illustrate what happens to fuel flow should there be a voltage drop (as could happen without the BAP), and the 17.5 volt numbers better extrapolate fuel flow at a moderate voltage increase:
Again, it is obvious the stock pump has a generous flow capacity—remember when Fox Mustangs came with 88-lph pumps? And the relationship between electrical power supplied to the pump and the resulting flow and pressure is easily seen.
The other three pumps we'll look at are the Aeromotive Stealth, the TI 400, and the venerable Walbro 225. This last pump has been around for about a decade and is used in many performance applications, so it's a familiar Mustang upgrade.
On the other hand, the TI Automotive 400 is new. Its official name is the TI 90000262, and it's a real squirter that puts out big numbers. Likewise, the Aeromotive Stealth is another well-respected pump from that long-time racing fuel system specialist:
Horse Sense: Boost-referenced systems work OK until the system voltage drops and the fuel pump slows down, causing the engine to lean out and detonate. A BAP keeps voltage elevated to guarantee sufficient fuel supply. Curiously, headlights are the primary culprit of voltage drops.
|Stock Coyote Pump at 12 Volts|
|Stock Coyote Pump at 13.5 Volts|