Electric Fuel Pumps

[Carl Summers]

Hi Greg,
     Unless you plan on running some sort of large accumulator the
mechanical/gear driven pump will cause many tuning problems on shift as
engine rpm goes down and so does pump....fought that on that 1600hp boat
engine with the turbo 400.. the fuel pressure would drop to below 20 psi on
upshift and lean backfire....crazy thing was (not so crazy though, less
torque meant more drastic rpm changes on upshift)it was worse the easier you
were on the throttle so didn't notice it as bad until I was going back over
the driveability stuff after verifying full throttle....thank god for
datalogging....would have never found it...ended up with an elctric fuel
pump set up to run while in 1st and 2nd gear and shut off in third...got
that straightened out and no probs other than the normal retune from the
engine dyno to the real world...just some insight...ttyl
-Carl Summers

-----Original Message-----
From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
Behalf Of Greg Hermann
Sent: Thursday, February 10, 2000 11:01 AM
To: diy_efi at diy-efi.org
Subject: Re: Electric Fuel Pumps

Hi Walt--

Didn't realize that you had good pump data at hand!

I have been pondering using a primary in tank pump, only need maybe 7 to 10
psi output,  but 60 to 80 GPH would be a good idea. Thinking I will use a
mechanically driven gear type secondary HP pump to feed the rails. The
mechanical pump is no problem to come up with or drive, but I (naturally)
want something quite reliable and relatively insensitive to dirt in the
tank.

Electrical system will be 24 vdc. I have been thinking pretty seriously
about just using a 24v. marine centrifugal bilge pump in the tank--35
HUNDRED GPH, but just run it right up near the (about 7 psi on gasoline)
stall head on its curve--very nearly constant output as to pressure that
way at such a low flow rate for the pjmp's size, and thus be able to make
whatever primary fuel flow I need in a laugh. And--at such a low peak flow
rate relative to the size of the pump, relatively low current requirement
for the pump motor, and hence very reliable and cool running. Clearly not
sensitve to dirt, either.

Any thoughts or other suggestions for an in-tank pump that would fill this
general need??

I would think that running a HP in-tank fuel pump , but regulated to the
low output pressure I need, but at 24 v instead of 12 v. MIGHT just goose
the (pump speed and) volume of a fairly ordinary in-tank pump up to what I
need with no adverse effects on the pump motor so long as the load on it
was light due to the low pressure---

Regards, Greg


----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org