Info appreciated on instructions for modifying a Ford small block six mechanical fuel pump for boost referencing. Latest project is a Supercharged blow-through Carburetor setup and want to modify a mechanical pump for boost referencing while testing various components. thanks Ford small block six 250/Vortech V2/ modified Holley 2300-350/Maverick 3OTT Toploader for awhile... .] . . . Wired up an electric pump relay with safety oil pressure switch for the Maverick but still need to install a return line for a TB fuel injection type @45 PSI electric pump with bypass type Aeromotive Fuel Pressure Regulator with boost reference port.
Looks good! I don't have an answer for that type of mod because I've never seen anyone using it on a low pressure mechanical pump before. Or if I did I never cared to pay enough attention to what the added plumbing was for. Besides, no matter what you do that OEM pump the flow potential will only decrease as the rpm goes up anyways. Upping pressure only gets you so far to improve it and it'll likely never reach what you'd want anyways as it'll just lift the needle and cause much bigger issues. Trying to set it lower at idle/off-idle will also potentially drop the bowls fuel levels to uncover the emulsions and then come back up at higher pressures to have you chasing AFR's along the way till you're damned near bald. AFAIK, only the mechanical pumps pressure regulator(but does that little pump really even need a regulator anyways though?) and carb's power valve would need to be referenced. PS. hopefully you don't intend to get too carried away with boost levels running that heavily limited pump. I can't see it being very safe above 5-6 psi but others with more experience would surely be better advisors on the subject. Good luck with it.
To boost reference the stock pump you will need to jb weld a piece of 3/16 brake line in the weep hole and plug the other side if it is a through and though style weep hole. If you have any money in that motor or better yet if you don`t enjoy changing your pistons more often than your oil then invest in a good wide band o2 sensor. how much boost do you plan on running with that ? www.theturboforums.com has lots of info
I just saw you are running a two barrel holley check out the http://www.hangar18fabrication.com/blowthru.html also check out "the crutch" wich is pretty easy to do on a two barrel
Thanks for the replies, also seeking advice on the TurboForums but post here since the project is a Maverick and give other six cylinder Maverick enthusiasts some performance options. I found this simple mod to a use a big Chevy pump @120 gph/9PSI and boost reference if needed: http://www.classicinlines.com/fuelpump.asp ' working toward the Fuel supply finish, use a wideband AFR , pre/post boost gauge, Hangar18 mod'd 7448-2300 - jets and PV circuit . still figuring out the XSTurbo Hybrid BOV borrowed from a WRX'er. Actually Maverick's first drive AFR's (@ 12-14) were good thru light boost cruise. but went pig rich under wider throttle/more boost until fuel starvation - then my AEM AFR gauge went DEAD. I can't see trying to tune anything until I replace AFR meter ... have fun
That is a really cool setup! Hope you get it figured out. I'm interested to hear what kind of power and fuel economy this thing develops.
