Hello all,

I currently run a Bosch 044 external inline with a Walbro 255 in-tank pump.

According to the AMS Fuel Pump Test... the Bosch 044 does not seem to flow much more than a modified Walbro in-tank. I found this a bit odd, but anyway, it made me think maybe I should switch to the twin in-tank setup.

My question is... what happens if one the in-tank Walbros fails? I've had a Walbro fail on me before, so I have some concern about this.

With my setup, if either the Bosch or the Walbro fails, I'll basically get zero flow and the car won't go anywhere. But in the in-tank setup, I'm thinking there is a chance of going dangerously lean up top.

Thoughts?

 

I went real lean on the dyno but it was after 3 pulls. WE were at 60 than 70 than 90% duty cycle at the same boost level after each pull is how we caught our bad pump

 

How was the duty cycle changing? Were you tuning the fuel table during the pulls?

I'm starting to believe running pumps in series in-line is much safer because if any pump in the chain fails you will get such little pressure the car won't go anywhere or will feel like fuel cut as soon as you come in boost.

With the in-tank, your just gonna run lean up top it seems to me.

 

Running the pumps in series does not provide a significant increase in flow over a single pump, so it's hardly worth doing.

-Paul

 

Thats a good point. Maybe just run single pump, with an in-tank feeding it. Then just make sure your single pump is big enough to handle whatever you throw at it?