Fuel Pump Shootout Part 2 - Fueling For Power

We took you through a battery of fuel pump testing last month, while including a showdown of real versus "fake" fuel pumps. Continuing where we left off, our second part focuses on testing a number of OEM fuel pumps including some of the newer high performance models available on the market today. Keep in mind that our documented pump dyno numbers don't necessarily reflect your unit's performance and, with any dynamometer, numbers can vary from one unit to another. The most important thing to take away from this story is to understand the capabilities of your OEM/aftermarket pump and the importance of maintaining proper fuel delivery.

Higher fuel pressure (PSI) = less fuel?

The fuel pump is one of the most important components in an internal combustion engine. Keep in mind that fuel pumps supply fuel volume; they do not produce nor create the necessary pressure in the fuel lines. Turbocharged cars using a boost dependent fuel pressure regulator will witness fuel spikes as high as 100 psi when initially stomping on the gas pedal at WOT. As the fuel supply line pressure increases to compensate for fuel, the pump literally begins to slow down as it tries to push the needed fuel from the tank to the injectors. As shown in all dyno figures for RC Engineering's testing, in relation to psi pressure and flow characteristics, the numbers (flow) begin to fall significantly when pressure and amperage increase due to load.

For boosted applications, because the numerical boost value is added on top of the base fuel pressure, it's vital that the pump delivers the necessary volume at the elevated fuel pressures. So while a pump puts out healthy numbers at 3 bar, if you're boosting 2 bar it needs to put out the necessary volume at 5 bar. This is something to consider for those who have upgraded to larger-sized injectors but refuse, or simply haven't had the time or money, to replace your OEM fuel pumps.

Voltage Regulating

When testing our pumps on the RC Engineering fuel pump dynamometer, RC used a set voltage of 13.5 amps to display the flow characteristics associated with the increase in voltage. In side-by-side comparisons of flow characteristics in correlation to an increase in voltage, amperage ratings as well as flow capacities were significantly higher as psi levels were raised. With most vehicles today, 13.5 V is the normal operating voltage for a fuel pump. As fuel demands increase, however, and audio systems and various interior and exterior components are being used, it causes a draw in amperage in the car and fluctuation in power output, rendering the fuel pump to increase and decrease in flow. To remedy the problem and keep voltage consistent, or if looking to increase voltage, manufacturers such as Aeromotive (Billet Electric Fuel Pump Controller) offer fuel pump boosters with excellent proven results. At low fuel demand the FPSC slows the fuel pump's duty cycle and fuel rate, which in turn reduces the unnecessary pick up of residual heat from the engine compartment. As demand increases, the FPSC returns the fuel pump to 100 percent duty cycle for maximum flow using pulse modulation technology.

"Increasing the voltage is actually a great method of getting a bit more flow if you need it. The fuel pump is one of the few components that aren't designed to work at the traditional 12-13 V. As far as any decrease in longevity, RC doesn't have any long-term data to support voltage versus longevity, but we can assume if you're taxing your fuel pump with excessive voltage, it's going to experience a shorter life span," says RC Engineering representative John Park.

Added Insurance

A large majority of owners sporting high horsepower vehicles, such as the R34 Skylines and Supra TT, have implemented a dual or triple fuel pump system with much success. Running two or three pumps inside the fuel tank enables dozens of RB26 or 2JZ engines to push the 1,000-plus horsepower marker with peace of mind that sufficient fuel is being adequately delivered to each injector at high rpm. When using a multiple pump setup, it is imperative to rewire each pump separately rather than splicing both pumps into the single wire factory circuit. Using the same wire inline causes an overload in amperage within the wires and significant loss in voltage, causing less fuel flow than using the typical single pump method.

"Using multiple pumps (assuming there is enough space) is another way of increasing volume and pressure handling capabilities. Although you don't necessarily get twice the amount of fuel, the increase in overall flow is substantial and works well for a variety of applications," Park says.

Drawbacks with using more multiple fuel pumps is the additional cost of purchasing two to three fuel pumps, placement of multiple pumps in the fuel tank, rewiring the factory fuel system, and, if necessary, adding additional voltage regulator units dedicated to each fuel pump. Of course there's always the issue of one or more pumps going faulty.

Surge Tank

A general rule of thumb is that every gallon of gas is equivalent to 5.8-6.5 pounds (weight vary is dependent on temperature). Let's say you're at the track and we measured out the gasoline to be 6 pounds per gallon. If you filled your 14-gallon Evo IX tank (notorious for suffering from fuel starvation at 1/4 tank empty) to max capacity, the total weight would be 84 pounds. That's dead weight to consider in an event that doesn't require weight penalty or need to run more than three laps per session. So what's a simple yet effective solution for those weekend track warriors looking to enjoy a little quarter-mile run or apex carving session without running into dangerously lean conditions? It's simply called a surge tank.

The theory behind a surge tank is simple. Fuel is stored in an external unit while being placed between the factory in-tank pump and lines leading to the engine. Fed by the pump, the unit prevents fuel starvation due to hard cornering, braking, and acceleration by storing additional fuel into the aluminum surge tank. Fed through an inline pump, the surge tank supplies an ample amount of fuel into your engine, should the OEM tank ever experience a hiccup or starvation from its design. A fuel surge tank offers a little added insurance for the hard-core drag, road race, or autocross enthusiast who plans on racing his vehicle without the fear of damaging the engine.

Integrated Engineering recently released a new concept in surge tank design with a billet system using a single or dual Bosch 044 fuel pump(s). This ingenious design keeps the pump body submerged over 75 percent inside the tank. Using the fuel to submerge the pump muffles the noisy pump, provides cooler pump operating temperatures for longer life, and ensures it will have fuel even on steep turns or accelerations where the OEM pump could experience fuel starvation.

Unisia JECS WRX vs. Unisia JECS STI Fuel

Make: Unisia JECS 02-05 WRX 130 LPH
Pump: None
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

Making an apples-to-apples comparison between these two pumps would be unfair due to the fact that the '02-05 WRX pump is rated at 130 lph and the '05 STI fuel pump is 145 lph, but we grouped both together to identify two OEM fuel pumps from the same vehicle type/manufacturer. The WRX pump starts strong but quickly begins to stumble as fuel pressure is increased. Notice a significant drop in fuel delivery once the bypass valve opens at 75 psi. The bypass is designed to extend the longevity of the pump should a spike in pressure occur, but this safety measure often spells disaster for a high-performance car with high boost/horsepower applications.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 6.2 274 45.67 172.87 2.88 2881.19 2071.46 34.52 498.2 40 6.4 260 43.33 164.04 2.73 2733.97 1965.62 32.76 472.7 45 6.7 250 41.67 157.73 2.63 2628.82 1890.02 31.50 454.5 50 6.9 234 39.00 147.63 2.46 2460.58 1769.06 29.48 425.5 55 7.2 220 36.67 138.80 2.31 2313.36 1663.21 27.72 400.0 60 7.3 205 34.17 129.34 2.16 2155.63 1549.81 25.83 372.7 65 7.6 190 31.67 119.87 2.00 1997.90 1436.41 23.94 345.5 70 7.8 167 27.83 105.36 1.76 1756.05 1262.53 21.04 303.6 75 8 142 23.67 89.59 1.49 1493.17 1073.53 17.89 258.2 80 8.2 109 18.17 68.77 1.15 1146.17 824.05 13.73 198.2 85 8.4 74 11.60 43.91 0.73 731.86 526.18 8.77 134.5 90 8.7 25 4.17 15.77 0.26 262.88 189.00 3.15 45.5

Note: Bypass valve opens at 75 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

Make: Unisia JECS 2005 STI 145LPH
Pump: None
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

The STI fuel pump fares better than the WRX unit, but, similar to its counterpart, the pump quickly degrades in fuel delivery once the bypass opens at 75 psi. It recorded a modest 17.67 lph at 85 psi.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 6.9 311 51.83 196.22 3.27 3270.25 2351.18 39.19 565.5 40 7.1 297 49.50 187.38 3.12 3123.04 2245.34 37.42 540.0 45 7.3 278 46.33 175.39 2.92 2923.25 2101.70 35.03 505.5 50 7.5 261 43.50 164.67 2.74 2744.49 1973.18 32.89 474.5 55 7.7 246 41.00 155.21 2.59 2586.76 1859.78 31.00 447.3 60 7.9 229 38.17 144.48 2.41 2408.00 1731.25 28.85 416.4 65 8.1 212 35.33 133.75 2.23 2229.24 1602.73 26.71 385.5 70 8.4 197 32.83 124.29 2.07 2071.51 1489.33 24.82 358.2 75 8.6 168 28.00 105.99 1.77 1766.57 1270.09 21.17 305.5 80 8.7 138 23.00 87.07 1.45 1451.11 1043.29 17.39 250.9 85 8.9 28 4.67 17.67 0.29 294.43 211.68 3.53 50.9

Note: Bypass valve opens at 75 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

DeatschWerks DW65C

Make: Deatschwerks DW65C 265 LPH
Pump: 120320
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

Dimensionally the smallest pump in our test, this modest-sized unit surprised us by delivering big numbers. Designed to fit in vehicles like the '08-and-newer WRX/STI, BRZ, and Scion FR-S models, this 320-lph unit at 9.3 V and 50 psi flowed a respectable 249.21 lph and rated at 718.2 BHP. Marketed by DeatschWerks as the world's first 65mm bodied high-performance pump, the DW65C's turbine impeller ensures longevity and is also ethanol compatible.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 8.4 441 73.50 278.23 4.64 4637.24 3333.99 55.57 801.8 40 8.6 426 71.00 268.77 4.48 4479.51 3220.59 53.68 774.5 45 8.9 409 68.17 258.04 4.30 4300.75 3092.07 51.53 743.6 50 9.3 395 65.83 249.21 4.15 4153.53 2986.23 49.77 718.2 55 9.6 381 63.50 240.38 4.01 4006.32 2880.38 48.01 692.7 60 9.9 363 60.50 229.02 3.82 3817.05 2744.30 45.74 660.0 65 10.2 348 58.00 219.56 3.66 3659.32 2630.90 43.85 632.7 70 10.4 327 54.50 206.31 3.44 3438.50 2472.14 41.20 594.5 75 10.8 311 51.83 196.22 3.27 3270.25 2351.18 39.19 565.5 80 11 292 48.67 184.23 3.07 3070.46 2207.54 36.79 530.9 85 11.3 275 11.60 43.91 0.73 731.86 526.18 8.77 500.0 90 11.6 259 43.17 163.41 2.72 2723.46 1958.06 32.63 470.9 95 11.9 239 39.83 150.79 2.51 2513.15 1806.86 30.11 434.5 100 12.3 220 36.67 138.80 2.31 2313.36 1663.21 27.72 400.0

Note: Bypass valve opens at 75 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

AEM High-Flow Fuel Pump

Make: AEM High-Flow 320 LPH
Pump: 50-1000
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

AEM might be considered a newbie to the fuel pump market but don't let their adolescence fool you. The newest fuel pump to the AEM lineup is rated at 320 lph at 43 psi and is a direct drop-in unit that can be used for both naturally aspirated and forced induction vehicles. Upon testing the unit, we found the pump to offer rock-solid voltage fuel flow stability throughout the entire test, which was a common problem among the cheaper "knockoff" models we had tested in part one.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 10.5 514 85.67 324.29 5.40 5404.85 3885.87 64.76 934.5 40 10.9 494 82.33 311.67 5.19 5194.55 3734.67 62.24 898.2 45 11.2 475 79.17 299.69 4.99 4994.76 3591.03 59.85 863.6 50 11.6 453 75.50 285.81 4.76 4763.42 3424.71 57.08 823.6 55 12 435 72.50 274.45 4.57 4574.15 3288.63 54.81 790.9 60 12.4 420 70.00 264.99 4.42 4416.42 3175.23 52.92 763.6 65 12.7 404 67.33 254.89 4.25 4248.17 3054.27 50.90 734.5 70 13.1 387 64.50 244.16 4.07 4069.41 2925.74 48.76 703.6 75 13.4 362 60.33 228.39 3.81 3806.53 2736.74 45.61 658.2 80 13.8 346 57.67 218.30 3.64 3638.29 2615.78 43.60 629.1 85 14.3 330 55.00 208.20 3.47 3470.04 2494.82 41.58 600.0 90 14.6 306 51.00 193.06 3.22 3217.68 2313.38 38.56 556.4 95 15 280 46.67 176.66 2.94 2944.28 2116.82 35.28 509.1 100 15.6 238 39.67 150.16 2.50 2502.64 1799.30 29.99 432.7

Note: Bypass valve opens at 95 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

DeatschWerks DW200

Make: Deatschwerks DW200 255 LPH
Pump: 120328
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

Able to deliver 255 lph, the DW200 is bargain priced, offering bang for the buck in performance. While the performance numbers came in a bit lower than the 65C, the DW200 was still able to post up good numbers with 232.81 lph at 50 psi, solid numbers that are able to support 670 bhp.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 8.6 400 66.67 252.37 4.21 4206.11 3024.03 50.40 727.3 40 8.9 389 64.83 245.43 4.09 4090.44 2940.86 49.01 707.3 45 9.1 380 63.33 239.75 4.00 3995.81 2872.82 47.88 690.9 50 9.4 369 61.50 232.81 3.88 3880.14 2789.66 46.49 670.9 55 9.6 356 59.33 224.61 3.74 3743.44 2691.38 44.86 647.3 60 9.8 345 57.50 217.67 3.63 3627.77 2608.22 43.47 627.3 65 10.1 334 55.67 210.73 3.51 3512.10 2525.06 42.08 607.3 70 10.4 316 52.67 199.37 3.32 3322.83 2388.98 39.82 574.5 75 10.7 310 51.67 195.58 3.26 3259.74 2343.62 39.06 563.6 80 11 302 50.33 190.54 3.18 3175.61 2283.14 38.05 549.1 85 11.3 289 48.17 182.33 3.04 3038.92 2184.86 36.41 525.5 90 11.5 275 45.83 173.50 2.89 2891.70 2079.02 34.65 500.0 95 11.8 257 42.83 162.15 2.70 2702.43 1942.94 32.38 467.3 100 12.1 234 39.00 147.63 2.46 2460.58 1769.06 29.48 425.5

Note: Bypass valve opens at XX psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

Denso Evo IX Fuel Pump

Make: Denso 2006 EVO IX MR 190 LPH
Pump: None
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

There's no surprise that the Evo IX still remains a popular tuner vehicle, but more often than not Evo owners on various Internet forums have a mindset of refusing to replace their OEM pumps. We decided to test a low mileage pump and revealed that although it performed better than the OEM STI fuel pump. Not only was the rated 190 lph seemingly generous, the Evo pump also lacked the necessary fuel demand needed at higher psi levels. At 80 psi it was shown to reap its limit; it delivered a modest 106.62 lph with a rating of 307.3 BHP.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 10.3 336 56.00 211.99 3.53 3533.13 2540.18 42.34 610.9 40 10.6 316 52.67 199.37 3.32 3322.83 2388.98 39.82 574.5 45 10.9 293 48.83 184.86 3.08 3080.98 2215.10 36.92 532.7 50 11.3 277 46.17 174.76 2.91 2912.73 2094.14 34.90 503.6 55 11.6 259 43.17 163.41 2.72 2723.46 1958.06 32.63 470.9 60 11.9 241 40.17 152.05 2.53 2534.18 1821.98 30.37 438.2 65 12.2 222 37.00 140.06 2.33 2334.39 1678.33 27.97 403.6 70 12.4 204 34.00 128.71 2.15 2145.12 1542.25 25.70 370.9 75 12.8 189 31.50 119.24 1.99 1987.39 1428.85 23.81 343.6 80 13.2 169 28.17 106.62 1.78 1777.08 1277.65 21.29 307.3 85 13.5 140 23.33 88.33 1.47 1472.14 1058.41 17.64 254.5 90 13.8 112 18.67 70.66 1.18 1177.71 846.73 14.11 203.6 95 14.2 86 14.33 54.26 0.90 904.31 650.17 10.84 156.4

Note: Bypass valve opens at 85 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

Denso Supra TT Fuel Pump

Make: Denso Supra TT OEM 260LPH
Pump: 195130-1020
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

This Denso pump has remained a popular upgrade among vehicles varying from Subarus to Hondas as an alternative thanks to high flow and reliability. At 260 lph, the Denso pump delivers an abundance of fuel but comes with a trade-off of being expensive when purchased new and it's bulky in size, which limits interchangeability in many in-tank fuel systems.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 15 530 88.33 334.39 5.57 5573.10 4006.83 66.78 963.6 40 15.2 513 85.50 323.66 5.39 5394.34 3878.31 64.64 932.7 45 15.5 492 82.00 310.41 5.17 5173.52 3719.55 61.99 894.5 50 15.6 469 78.17 295.90 4.93 4931.67 3545.67 59.09 852.7 55 16 450 75.00 283.91 4.73 4731.88 3402.03 56.70 818.2 60 16.2 420 70.00 264.99 4.42 4416.42 3175.23 52.92 763.6 65 16.5 396 66.00 249.84 4.16 4164.05 2993.79 49.90 720.0 70 16.7 370 61.67 233.44 3.89 3890.65 2797.22 46.62 672.7 75 17 341 56.83 215.14 3.59 3585.71 2577.98 42.97 620.0 80 17.1 302 50.33 190.54 3.18 3175.61 2283.14 38.05 549.1 85 17.4 262 43.67 165.30 2.76 2755.00 1980.74 33.01 476.4

Note: Bypass valve opens at 85 psi
Horsepower value at BSFC of 0.55 is shown in last column at right.

DeatschWerks DW300

Make: Deatschwerks DW300 340LPH
Pump: 120406
Volts: 13.5
Test Fluid S/G: 0.76
Fluid Temp: 69

The DW300 is the largest drop-in unit DeatschWerks has to offer, delivering 340 lph (90 gph) with the capability to support over 1,000 bhp. Offered as a direct drop-in kit for numerous import vehicles, the DW300 flowed an impressive 270 lph at 60 psi with a horsepower value supporting 778 bhp. Unsure of your fueling needs? Check out DeatschWerks' website to use their fuel pump calculator to determine proper fueling for your car.

PSIG Amps Lbs/Hr Gal/Hr Ltr/Hr Ltr/Min CC/Min Gr/Min Gr/Sec BHP 35 12.9 521 86.83 328.71 5.48 5478.46 3938.79 65.65 947.3 40 13.4 505 84.17 318.61 5.31 5310.22 3817.83 63.63 918.2 45 13.7 484 80.67 305.36 5.09 5089.39 3659.07 60.98 880.0 50 14 469 78.17 295.90 4.93 4931.67 3545.67 59.09 852.7 55 14.4 449 74.83 283.28 4.72 4721.36 3394.47 56.57 816.4 60 14.7 428 71.33 270.03 4.50 4500.54 3235.71 53.93 778.2 65 15 410 68.33 258.68 4.31 4311.26 3099.63 51.66 745.5 70 15.5 390 65.00 246.06 4.10 4100.96 2948.43 49.14 709.1 75 15.9 370 61.67 233.44 3.89 3890.65 2797.22 46.62 672.7 80 16.1 353 58.83 222.71 3.71 3711.89 2668.70 44.48 641.8 85 16.5 324 54.00 204.42 3.41 3406.95 2449.46 40.82 589.1 90 16.8 308 51.33 194.32 3.24 3238.71 2328.50 38.81 560.0 95 17.2 286 47.67 180.44 3.01 3007.37 2162.18 36.04 520.0 100 17.5 266 44.33 167.82 2.80 2797.06 2010.98 33.52 483.6

Note: Bypass valve opens at XX psi
Horsepower value at BSFC of 0.55 is shown in last column at right.