• Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

70NE's custom EFI conversion writeup - Part 2

  • Thread starter Thread starter ForceFed70
  • Start date Start date Jan 3, 2006
Prev
  • 1
  • 2
First Prev 2 of 2

68converted

Member
Nov 19, 2003
772
0
16
Colorado
Jan 4, 2006
#21
  • Jan 4, 2006
  • #21
70_Nitrous_Eater said:
The main concern is air in the fuel lines. We need a way of getting as much of this air out as possible without the air going through the injectors. Even with baffles in the tank you will run into instances when air is sucked into the system (Bubbles,sloshing, low tank, hard launch, etc).

A carb can "burp" the air out through the floats. But the only way to "burp" an EFI system is back into the fuel tank.

This means there must be a path the air can travel all the way back to the tank.



What you describe here is 1/2 of a "surge tank" setup. Check out this webpage for a great description of what a surge tank is and does. http://toyotaperformance.com/surge_tank.htm
Click to expand...

What I was thinking is a return line to the tank but adding the extra line prior to the tank to take advantage of the extra returning fuel using a low loop to allow air, if any to head to the tank, while the fuel goes to the pump in the on position. The other idea I had was using the filter as a storage or header tank. (dual purpose) They make some larger filters that would hold at least 2 quarts.
 
F

ForceFed70

That's why they call it "dope"
Founding Member
Dec 6, 1999
4,818
1
69
BC Canada
Jan 4, 2006
#22
  • Jan 4, 2006
  • #22
68converted said:
What I was thinking is a return line to the tank but adding the extra line prior to the tank to take advantage of the extra returning fuel using a low loop to allow air, if any to head to the tank, while the fuel goes to the pump in the on position. The other idea I had was using the filter as a storage or header tank. (dual purpose) They make some larger filters that would hold at least 2 quarts.
Click to expand...

The filter for a surge/header tank would work well. I've seen a few pictures of this done and it looks nice and clean.

I think I understand your idea about adding a 2nd line... but I don't think a regular fuel line will be wide enough to allow the air to properly seperate and rise to the "upper" path. The fuel moves through those lines awefully fast. When I put an ear to the filler neck, the fuel returning to the tank almost sounds like a garden hose running in there.
 

67coupe351w

New Member
Jan 31, 2004
424
0
0
Portland, OR
Jan 4, 2006
#23
  • Jan 4, 2006
  • #23
So actually after I went off half cocked and wrote the below I see the "surge tank link" is alot like what I decribed:
-------
I'm considering (and probably will use) a header tank for my Megasquirt install. I learned about it on a SN thread from a few weeks ago, i think it was called "EFI checklist".

But anyway, its a smaller tank (holds enough fuel to run the car for a few minutes) with a submersable pump in it., the header tank is fed by either gravity or a low pressure pump from the main tank to the header tank as well as the retun fuel is emptied into the header tank. Apparently the design was drempt up by Rock crawling efi conversion broncos who's baffless tanks become useless as they travel up the side of a rock.

I'm thinking that if I gravity feed the header tank from the main tank and run the return to the header tank I should be golden.

Suggestions? Comments? Concerns?
 
F

ForceFed70

That's why they call it "dope"
Founding Member
Dec 6, 1999
4,818
1
69
BC Canada
Jan 5, 2006
#24
  • Jan 5, 2006
  • #24
67coupe351w said:
So actually after I went off half cocked and wrote the below I see the "surge tank link" is alot like what I decribed:
-------
I'm considering (and probably will use) a header tank for my Megasquirt install. I learned about it on a SN thread from a few weeks ago, i think it was called "EFI checklist".

But anyway, its a smaller tank (holds enough fuel to run the car for a few minutes) with a submersable pump in it., the header tank is fed by either gravity or a low pressure pump from the main tank to the header tank as well as the retun fuel is emptied into the header tank. Apparently the design was drempt up by Rock crawling efi conversion broncos who's baffless tanks become useless as they travel up the side of a rock.

I'm thinking that if I gravity feed the header tank from the main tank and run the return to the header tank I should be golden.

Suggestions? Comments? Concerns?
Click to expand...

Yup.. same sort of thing, although putting the 2nd pump inside the tank is a new idea to me. I don't see why it wouldn't work.

Gravity feed may be difficult. There's not many places you could install a header tank that would be lower than the bottom of the fuel tank. If you were able to find a spot a little lower than the tank, I don't think the few inches of drop would be enough to get a fast enough flow of fuel.
 

red65

Member
Apr 12, 2003
411
0
17
Ann Arbor, MI
Jan 5, 2006
#25
  • Jan 5, 2006
  • #25
70_Nitrous_Eater said:
Yup.. same sort of thing, although putting the 2nd pump inside the tank is a new idea to me. I don't see why it wouldn't work.

Gravity feed may be difficult. There's not many places you could install a header tank that would be lower than the bottom of the fuel tank. If you were able to find a spot a little lower than the tank, I don't think the few inches of drop would be enough to get a fast enough flow of fuel.
Click to expand...

You'll need a low pressure pump to keep the header tank full. I don't think you could gravity feed it fast enough (unless you can rig 3" fuel lines...lol).
 

jikelly

20+ Year Stangneter
Jul 9, 2003
872
53
99
Lubbock Tx
May 11, 2006
#26
  • May 11, 2006
  • #26
bump
 
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

0
V6 to V8 Swap info
  • 02_2v_Curtis
  • Jan 11, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
582
1996 - 2004 SN95 Mustang -General/Talk- Jan 11, 2026
02_2v_Curtis
0
Place to Avoid: Jamison Auto Group in Gulfport, MS
  • D Durden
  • Oct 20, 2025
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • 2 3
Replies
45
Views
2K
1965 - 1973 Classic Mustangs -General/Talk- Feb 4, 2026
nickyb
M
Progress Thread mnky99 2001 V6 evap core, ac compressor, heater core replacement
  • mnky99
  • Sep 5, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
427
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
What's your tow rig?
  • LILCBRA
  • May 31, 2026
  • Other Auto Tech
Replies
3
Views
69
Other Auto Tech May 31, 2026
LILCBRA
S
Requesting Guidance for 306 motor swap - Fuel? - SD? MAF?
  • So_Flo
  • Jul 26, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
32
Views
2K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jan 4, 2026
Mcmahst
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?