On my 87 vette, I run a Walbro 255 in the tank with an additional booster (high psi) pump located under the tank to power the motor, all feeding 1/2" supply and 3/8" return lines. Additionally, there is a parallel Walbro 255 feeding a dedicated 3/8" line for the N20 with 5/16" return. I do not currently (probably 5-6 years) use the N20, so that pump has just been running for nothing. At least I think it still runs (maybe I should check the psi in the N20 fuel delivery system).

Lately, the A/F ratio is dropping off (going lean) at the top of the gears if you slow/moderately take the car up. The injector duty cycle is running in the very high 90% are when this occurs. If you hammer through the gears, it is not quite so noticeable, but the duty cycle still approaches 100%.

I am thinking that after 7 years, I have exceeded the capacity of these very capable Walbros. I was looking at the Weldon D2015A (rated by Weldon for 1000 HP; 405LPH) or the D2025A (rated by Weldon at 1500HP; 620LPH). Is there anything decent (no Aeromotive) in between the 255LPH (Walbro) and the Weldon series of pumps that I should be looking at. Can these type pumps draw over the top of the tank, or is it time to go to a sump in the fuel tank? Anyone know if these pumps are noisy?

I would like to step up without taking risks with the motor.

Thanks,
Aaron

 

The Weldon pumps scream. They're noisy. They do work well. The 2015 is a continuous duty pump, the 2025 or bigger pumps require a voltage step down box to run continuosly. I've run the 2015 to 822 rwhp with ~80 psi fuel pressure and larger fuel line dia's than your talking about. -12 from the tank to pump, -10 to the fuel rails, -8 returns. 60% duty cycle using 160 pph injectors. 14.8 volts at the pump. I was pretty much out of pump at that point. A friend of mine maxed the 2025 at 1060 rwhp.

Aeromotive pumps have been reworked in the last year or so.

If noise is a problem, I like to take (2) 255 pumps and Y them together in the tank to a single -8 or larger line. That booster pump in line is a restriction to total fuel volume.

 

Aaron
You can do a twin 255 inside the tank, you can Y them together or run them each to the rail. Mine fuel rail each got a 255lph pump using a -6 line.

Bruce

 

Try removing the in line pump and see if that helps.
The in line pumps I have found don't work, I had to remove mine I had the same problem as you.
Try the worbor 20000169 they came out in april 04 that is what I run.

 

I ordered the Weldon yesterday, with an inline filter to be mounted just prior to the pump. This pump with the 1/2" fuel line should handle anything my motor will produce.

As a side comment of interest, the people I talked to were amazed at the fact that the Walboro 255 was keeping up with the motor and attributed it to the low presssure required (due to larger 84 lb/hr injectors) and the 1/2" fuel feed line. Still, they were very suprised that a motor had not been hurt. TPIS, could not verify that I needed a new pump without psi readings off the fuel supply at WOT under full boost. I was not willing to take that chance.

Any tricks any of you may have taken in the gas take (short of installing a sump) that may ensure that gas stays at the suction under max accelleration?

Aaron

 

I used a Product Engineering pump (http://productengr.com/PE_4550.htm) and love it. I made a custom pickup to do the job. Best of all it's quiet. Pricey though.

-Mike