Fuel Pump Questions

[CobraSix]

Okay, Working with Al on MPFI set up for the Aussie head. I had a few questions regarding the fuel pump. Now From what I've read, the fuel pump for a MPFI systems needs to put out 40-45 PSI with enough flow for the application. Now since i also plan to turbo this set up, am I right to assume I'll need a pump that can put out 55-60 psi (since I plan as much as 15psi on boost). IS that correct?

I'm seen pumps from Holley and such that say for MPI systems but only put out 15 psi, am I missing something? Thanks.

Slade

 

[Anonymous]

Slade,

Generally speaking, at a minimum you will want to keep your fuel pressure the same number of psi above the max boosted psi as it had before supercharging. So if your MPFI had a nominal pressure of 40-45 psi in its normally aspirated configuration, and you plan to add 10 psi of turbo boost, you'll need a pump that puts out 50-55 psi.

Electric fuel pumps for Mk1 VW Rabbits with CIS (Continuous Injection System) may be a good choice. They mount externally to the fuel tank and put out 75 psi. They're a bit pricey new, but should be cheaper than aftermarket "turbo" fuel pumps.

Check your local junk yard and eBay...75 psi ought to supply just about any MPFI/turbo setup...!

Edit: Those 15 psi pumps sound more like supply pumps than injector pumps. Even Holley's TBI unit uses 20-30 psi at the injector, IIRC.

 

[Anonymous]

Slade,

You should look at the flow and HP ratings also. You want to run 15psi? Properly done, 15 psi on a 200 can produce over 400HP. I don't think a pump from a VW Rabbit willl support that.