Solution to EFI w/o tank sump?

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Garys 68

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I ran across this article where a marine vapor separator tank (VST) is used on a vette EFI system. On boats it's designed to prevent vapor lock and avoid the use of a return line to the fuel tank.
On a EFI converted car without in tank sump or baffles using this could prevent fuel sloshing/starvation in cornering. It's more or less just a sealed carb bowl with needle valve/float and an EFI pump reservoir/sump.
These were an overcomplicted solution to the no return line issue in boats and were frequentlt thrown away and replaced with a simpler, cheaper system.
I'm going to see if I can find a free one to play with.
http://www.vetteweb.com/tech/vemp_0701_1965_chevrolet_corvette_efi_system/index.html
 
I put DPFI on my '72 when I got it, sometime in '95 or so....that slosh problem was a bugg a boo about the install for a long time, I had tried various easy CHEEEEEP fixes for it, and never found one that worked nicely....so I tolerated an effective ~16 gallon tank capacity.....then about 8 months? ago...

upon visiting Harbor Freight, I found a 20 buck 5 gallon compressed AIR tank.....about 8" dia, and maybe 16" long, round, with a bung on it...
drilled another hole in the end up top, and fed the main line from the top/stock tank to it, FI pump is still rear frame mounted, and sucks from bottom of the add on tank, via a copper tube down lo in the air tank, returns to the top of the air tank....using the stock '72 steel lines on the frame since I have had the car...3/8 line feeds engine, 1/4-5/16 line returns as always was....

vent for the small, now fuel tank, is up to the evap canister line...

the thing is heavy steel, mounted down forward and under the stock main tank....

so now I picked up 5 gallon capacity, and a very significant anti slosh ability I would have to be down to maybe less than a gallon in bottom of the 'new tank'....

BTW, I cross drilled the fuel pipe at the mounting flange in the stock tank, that lets fuel drain much more reliably into the small tank, and cut off the fuel strainter/sock....the OEM assy now just holds the tank lever sender...so when it's dead empty....I figger another 80 miles at most....

:smash::smash::thumbs:

took me a while to figger out how to plumb that thing to make it work, but it's finally fine now....

:lol::lol::smash:
 
Similar things have been around for ages, a reservoir w/ 1 or 2 Holley float bowls on the ends. Surge, Header or Puke tank for Mech Injection.

Rons has them w/ 1 float bowl (rons rape city has rons rape city pricing!!)
http://www.ronsfuel.com/surge_tank.cfm

Crower used to have them w/ 2 bowls if you need that. Check the bay...they are on there every now and then.

If you find a 2 bowl Crower one, let me know...been looking for one forever,...same as crower small block chevy timing cover (it's an enderle one w/ enderle machined off and crower engraved where it said enderle LOL)
 
Never seen that before, but I'm new to FI.
Can you still fit the spare tire with the extra sump tank?
 
Garys 68 said:
Never seen that before, but I'm new to FI.
Can you still fit the spare tire with the extra sump tank?
Click to expand...

NO, with more modern wheels/tires I quit carrying a spare years ago...

IF you modded the carrier and stuck in one of them gimpy looking things it may fit, or maybe rig up a crank type thing like on a S10 pickup....

:nuts::rain:
 
I'm sorta dealing with the same thing now. I built a bit of a anti slosh system around my pick-up which is in the bottom of the tank in my '65. It's not perfect. Now with 6.0L conversion I was going to to run with no return line using the Corvette filter/regulator with the return line from the filter pointed up hoping any bubble would return to the tank. I have since decided to run a return line because I like the idea of the fuel circulating plus the 6.0 system has a vacuum dia that dumps more fuel at WOT which would be eliminated with no return.
Gary, are you using the Corvette filter/regulator on your conversion?
 
I used the walbro 255 pump and vette filter/regulator. I mounted both inside the frame back by the tank, passenger side. The return line is routed from the regulator a few inches back to the tank. My 68 tank already has a return line provision.
With that, I can still mount a spare.
Guess if I went with the surge tank, I could use a 6 psi electric pump in back, a surge tank with 02 f body pump up front.
 
I checked that 255lph fuel pump, sounds like a good choice. I've been using the common Ford truck frame mounted pump that everyone was using a couple of years ago. Makes 90psi. I mount it right to the two holes that mount the rear stud for the spare carrier so I also can have a spare. Fits perfect. When you mounted your fuel filter/regulator did you happen to mount it with the return up? As I mentioned that may make the air bubble go away.
 
The vette regulator is mounted with the return on top, but that's only because of ease in routing the hose to the tank. I'm not counting on that doing much in terms of getting any air out.
 
Great article. I'll be watching your progress on this.
 
Jsup said:
Great article. I'll be watching your progress on this.
Click to expand...
Jsup, any chance you recognize this efi pump? 2 screw terminal posts, outlet centered between. It can from the Merc vst off a 96 502efi motor. I was hoping it was an off the shelf item but now I'm thinking merc may have engineered on for just this application.
DSCN0009.jpg

DSCN0010.jpg

DSCN0011.jpg
 
Pretty big markup, considering it looks to be an efi pump for an acura, $41 at rock auto. Specs for it are 60-95 psi, 50gph, guessing that's adequate for an LS motor. Going to the parts store later today to confirm.
 
Not yet, someone else pointed me towards the acura/honda import pump and it looks like a perfect match. Besides, if you have to pay $600, it would be cheaper to have a fuel tank sumped. Now if you can put this setup together for under $100, it would be worth it.
I'm going to confirm it's the same one at the parts store and then get the fittings to mock it up this week.
 
Gary's 68 said:
Pretty big markup, considering it looks to be an efi pump for an acura, $41 at rock auto. Specs for it are 60-95 psi, 50 gph, guessing that's adequate for an LS motor. Going to the parts store later today to confirm.
Click to expand...

Its really a nicely packaged unit. I have mine taken apart, I'll post some pix of it. The bottom of the pump has the filter on it and the terminals and pump discharge are all o-ring sealed. The pump fits into a well that is fed (with fuel) by a sump that has a float valve in it.

The problem I see with using it in a car is that you would have to have another low-pressure electric pump feed the EFI pump. Either that or have the top of the Mercury unit lower than the bottom of the tank for gravity feed. The extra pump seems like a lot of trouble to go through and mounting the pump lower than the tank is just not feasible.
 
I've got one taken apart too. Have you figured out the vent? There seems to be a diaphram and spring that's connected to the low pressure feed line.
 
No luck on the acura pump. The threads, height, bottom mount pattern are all the same, but it's 1/4" larger diameter.
 
Garys 68 said:
No luck on the acura pump. The threads, height, bottom mount pattern are all the same, but it's 1/4" larger diameter.
Click to expand...

The housing I have will accomodate a 1/4" larger diameter. Do you have any more info on the Acura pump, pix or application?
 
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