Boost reference mechanical fuel pump

62Cometman

62Cometman

Well-known member
Hey everyone, i am working on getting my low buck boosted 170 and plan on just boost referencing the mechnical pump, however since my car has the vacuum wipers i figure thats not a possiblity? if it is let me know so i dont have to swap out to a different pump, but i was looking at the pump for the electric wiper cars but this also looks a little different and want to know if the same idea of drilling a hole on the actuated side of the diaphragm and plumbing boost to that hole to increase the psi 1:1. But since this unit looks like the inlet bolts to the bottom idk if there is a different way it has to be done?

electric pump
https://www.rockauto.com/en/moreinfo.ph ... 6036&jsn=9

vacuum pump
https://www.rockauto.com/en/moreinfo.ph ... 47&jsn=435
 
62Cometman":36ff99xw said:
Hey everyone, i am working on getting my low buck boosted 170 and plan on just boost referencing the mechnical pump, however since my car has the vacuum wipers i figure thats not a possiblity? if it is let me know so i dont have to swap out to a different pump, but i was looking at the pump for the electric wiper cars but this also looks a little different and want to know if the same idea of drilling a hole on the actuated side of the diaphragm and plumbing boost to that hole to increase the psi 1:1. But since this unit looks like the inlet bolts to the bottom idk if there is a different way it has to be done?

electric pump
https://www.rockauto.com/en/moreinfo.ph ... 6036&jsn=9

vacuum pump
https://www.rockauto.com/en/moreinfo.ph ... 47&jsn=435
Click to expand...

Yes for sure you can boost reference your current fuel pump since it has two separate pump diaframs with the one used only for boosting vacuum for the vacuum wippers. But the question is how good the vacuum wippers are going to work when only hooked up to that fuel pump vacuum sorce, hopefully you don't need to use them much. Good luck (y) :nod:
 
Well they barely work to begin with, so not much difference. I plan on changing to electric motor wipers eventually.
 
Depending on what you have planned, most current Blow-Through forced induction setups use a return to tank fuel supply with a boost referenced Bypass regulator. Referenced' mechanical FP may be possible but could limit performance options. Draw-Through turbo setups do not require boost referencing or return to tank regulator.

have fun
 
I know people have boost referenced the mechanical fuel pump, but I cannot see It being a good idea...Not sure about the combo pump you have, but on a regular fuel pump there is no seal between the diaphragm rod and the bushing bearing...You will suck oil air out of the crankcase under vacuum and into the intake and blow air into the crankcase under boost...Yes it won't be much depending on the rod to bushing clearance..
I also cannot help think that under long high high vacuum conditions that the high vacuum could overcome the fuel pressure spring and result in low fuel pressure ...I guess that not much fuel would be needed in those conditions.
 
drag-200stang":22pjlxvi said:
I know people have boost referenced the mechanical fuel pump, but I cannot see It being a good idea...Not sure about the combo pump you have, but on a regular fuel pump there is no seal between the diaphragm rod and the bushing bearing...You will suck oil air out of the crankcase under vacuum and into the intake and blow air into the crankcase under boost...Yes it won't be much depending on the rod to bushing clearance..
I also cannot help think that under long high high vacuum conditions that the high vacuum could overcome the fuel pressure spring and result in low fuel pressure ...I guess that not much fuel would be needed in those conditions.
Click to expand...
Inline check valve...
 
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