Walbro In-tank Fuel Pump Specs

Walbro has been making OEM pumps and aftermarket pumps for many years. A few years ago, they added in-tank high pressure pumps for fuel injected vehicles to their aftermarket line. Their two most popular aftermarket in-tank high performance pumps are their 190 ltr/hr pump and their 255 ltr/hr pump.

Their first FI pump was a 190 ltr/hr pump. It was created for the Mustang. It also fit in the Turbo Regals quite well. They recently created a modified version of the 190 ltr/hr pump so it can fit in many other pump hanger brackets (e.g. Probe, Miata, etc.). With a 12 volt power source, these pumps flow 190 ltr/hr at 0 psi, 155 ltr/hr at 40 psi.

Later, they created a 255 ltr/hr pump This pump has the same fittings as the original 190 ltr/hr pump. They later created another 255 ltr/hr pump to match the fittings of the Probe pump. Later, they discovered if the output fittings of the Probe pump were turned 180 degrees, that the pump would fit some other applications (RX-7, 1st-Gen DSM), hence a third 255 ltr/hr pump was born. These pumps flow 255 ltr/hr at 40 psi, and 285 ltr/hr at 0 psi.

GSS340, GSS342, and GSS341

Then, they put a different pressure-relief spring in a standard 255 ltr/hr pump. That raised the output of the pump above 50 psi of fuel pressure. Walbro builds all three versions of the original 255 ltr/hr pump in "high pressure" versions. Below is a table that compares the average flows of several pumps with a 12 volt source.

Fuel pump flow rates and current draw at 12 volts

Pressure (psi)	190 ltr/hr fuel pump (gal/hr)	190 ltr/hr fuel pump (amps)	"high pressure" 190 ltr/hr pump (gal/hr)	"high pressure" 190 ltr/hr pump (amps)	255 ltr/hr fuel pump (gal/hr)	255 ltr/hr fuel pump (amps)	"high pressure" 255 ltr/hr pump (gal/hr)	"high pressure" 255 ltr/hr pump (amps)
0	56	2.6	53	2.8	75	4.7	76	4.4
10	52	3.2	50	3.5	72	5.2	73	4.8
20	48	4.0	48	4.3	67	6.1	68	5.5
30	44	4.8	44	5.0	62	7.2	63	6.3
40	40	5.7	41	5.9	58	8.2	59	7.1
50	36	6.6	38	6.8	53	9.3	54	8.0
60	32	7.6	35	7.8	49	10.6	51	8.9
70	28	8.6	31	8.8	40	11.8	46	9.9
80	22	9.7	29	9.9	29	13.3	41	11.0
90	12	10.8	25	10.9	0	14.6	32	12.0
100	0	12.5	21	12.0			22	13.2
110			17	13.5			11	14.5
120			11	15.0			1	15.8

Fuel pump flow rate and current draw at 13.5 volts

Pressure (psi)	190 ltr/hr fuel pump (gal/hr)	190 ltr/hr fuel pump (amps)	"high pressure" 190 ltr/hr pump (gal/hr)	"high pressure" 190 ltr/hr pump (amps)	255 ltr/hr fuel pump (gal/hr)	255 ltr/hr fuel pump (amps)	"high pressure" 255 ltr/hr pump (gal/hr)	"high pressure" 255 ltr/hr pump (amps)
0	63	3.1	60	3.3	82	5.2	85	5.0
10	61	3.5	58	3.9	81	5.9	82	5.2
20	57	4.2	56	4.5	76	6.5	79	6.0
30	52	5.0	52	5.3	71	7.8	73	6.8
40	49	5.8	50	6.2	68	8.6	70	7.5
50	46	6.6	47	7.2	62	9.8	65	8.2
60	42	7.5	45	8.0	58	10.8	61	9.1
70	38	8.4	41	8.8	50	12.0	56	10.2
80	32	9.4	38	9.8	39	13.3	51	11.1
90	22	10.3	34	10.9	11	14.4	43	12.1
100	14	11.5	31	12.0	1	15.0	32	13.2
110		12.7	28	13.2			20	14.3
120			22	14.5			11	15.7
130			18	16.0				17.0

For folks that are more visual, here are some graphs.

Typical 155 ltr/hr pump
Typical 190 ltr/hr pump
Typical high pressure 190 ltr/hr pump
Typical 255 ltr/hr pump
Typical high pressure 255 ltr/hr pump

Actual numbers can vary. Data in these tables are from Walbro. Numbers are the average of 10 pumps selected at random from the production lines of the GSS242 [190 ltr/h], GSS307 [255 ltr/hr], and GSS340 [high pressure 255].

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