Running In tank walbro 255 with external pump

[FLG]

Quick question.

I've got an early model with dual pump setup. Currently run a 255 in tank and was just going to eliminate the stock external.

But I have a brand new external pump sitting here...

Would I be better off bypassing the external pump or installing the new external pump?

This is feeding a 400+ whp turbo m20

Last dyno session we had to cut short due to fuel issues.... I don't want that to happen again.

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[bmwdready347]

Was going to run same set up ,only the exsternal pump was a bosch 044 ,but the tuner guy just use in tank walbro

[dnguyen1963]

You have to compare the flow rates/pressures of both pumps. If your external cannot pump as fast as your internal that would create flow back pressure problem.

[FLG]

Thanks.

So bypass the external.

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[dnguyen1963]

Yes, the 255 should be sufficient enough.

[Mr. Tasty]

don't you have to find another pump carrier though?

[FLG]

Pump carrier for what? The in tank? No just had to shorten the metal line that the pump connects too. Soldered the wires to the stock connector. Done.

As for the external bypass I have double barb fittings for that.

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[Mr. Tasty]

so you by pass the return line too?

[FLG]

No didn't have to touch the return line.

Original setup is return line goes into the tank connects to bottom of pump as seen here (bottom left)



Now it just goes in the tank. Pump connects just like old one to the output. Hose clamped it to the return line to hold it in place.

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[Mr. Tasty]

nice, where did you find the pump the cheapest? One of my pumps is going out, and would rather not pay for the expensive bosch.

[FLG]

"tre" seems to have the best deal. I'm on my phone but if you don't find it I'll link you up later tonight

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