Fuel system design questions - Vintage Mustang Forums
 1Likes
  • 1 Post By jcoby
 
Thread Tools
post #1 of 10 (permalink) Old 04-09-2018, 04:38 PM Thread Starter
Senior Member
 
Join Date: Oct 2014
Posts: 110
Fuel system design questions

Right now I'm running a Holley carb and in the future I'd like to change to a FiTech TB system (or something similar). Since my current Mighty Mite fuel pump is having trouble fueling my relatively stock 302, I figured I'd start on the fuel system first.
I have a Walbro in-tank pump I'm setting up now. I got this Aeromotive regulator that is capable of feeding carb or EFI psi's.

My question is on the plumbing. The easiest thing I can think to do is put the regulator back by the tank and run one 3/8" line up front in the factory location. A quick return line to the tank and it's done.
Or, should I run the regulator up front and have a send and return line front to back? Advantages? Disadvantages?

In the future, I might want to strap a 7.3l turbo on this engine, like they did on Roadkill, since I have one of those turbos in my parts shed. That's why I'm doing EFI next, to help me tune it.

1966 Mustang 302ci 4r70w, csrp front discs, 8.8 rear, EPAS, Fitech for fuel
copracr is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 04-09-2018, 06:51 PM
Senior Member
 
Join Date: Aug 2010
Location: WNC
Posts: 397
FiTech and Holley TBI systems both have built-in regulators. All you need to do is supply high pressure fuel and plumb a return line.
67Modcoupe likes this.

1968 Mustang Coupe | 331 | T5 | FiTech EFI
jcoby is offline  
post #3 of 10 (permalink) Old 04-09-2018, 08:27 PM Thread Starter
Senior Member
 
Join Date: Oct 2014
Posts: 110
Quote:
Originally Posted by jcoby View Post
FiTech and Holley TBI systems both have built-in regulators. All you need to do is supply high pressure fuel and plumb a return line.
Right on, but I need to regulate the fuel psi for my current carb setup. And if I understand correctly, I can deadhead into the TBI setup if I supply fuel at 60psi.

1966 Mustang 302ci 4r70w, csrp front discs, 8.8 rear, EPAS, Fitech for fuel
copracr is offline  
 
post #4 of 10 (permalink) Old 04-10-2018, 09:13 AM
Senior Member
 
Join Date: Aug 2010
Location: WNC
Posts: 397
Quote:
Originally Posted by copracr View Post
Right on, but I need to regulate the fuel psi for my current carb setup. And if I understand correctly, I can deadhead into the TBI setup if I supply fuel at 60psi.
You can but I'd avoid a deadhead setup if possible. I'd put the regulator in the engine bay and remove it when you go EFI. Both the carb and EFI will be happier with a full length return system.

1968 Mustang Coupe | 331 | T5 | FiTech EFI
jcoby is offline  
post #5 of 10 (permalink) Old 04-10-2018, 09:57 AM
Member
 
SM94Cobra's Avatar
 
Join Date: Feb 2006
Location: Raleigh
Posts: 59
I just changed to a dead head set up on my Fitech set up with an Aeromotive in-tank set up. I previously had an external pump with feed and return going directly to and from the TB. I am in NC and I get a lot of heat from my big block set up with it being worse in the summer time, so the fuel was getting hot and would eventually vapor lock on longer drives. I just got the car running with no drive time yet, but it is up and running and I am expecting better results. I plumbed a supply and return line up the passenger side and put the regulator in the passenger side fender well with a deadhead feed directly to the TB. Have right at 60 PSI to the regulator and car runs idles and has good throttle response so far. Hoping to get it on the road this weekend. I tried to keep everything out of the engine bay heat, including the regulator, to avoid sending any heated fuel back to the tank. Trying to keep everything as cool as possible. FiTech has stated that dead head is not a problem as long as you have another regulator in place for fuel that is not used , otherwise it would over power the internal regulator.

http://forums.vintage-mustang.com/signaturepics/sigpic30626_12.gif
1969 S Code Mach 1
445 FE Stroker
TKO 600
Street or Track Suspension
SM94Cobra is offline  
post #6 of 10 (permalink) Old 04-11-2018, 08:54 AM
Senior Member
 
j persons's Avatar
 
Join Date: Aug 2010
Location: Natchitoches, LA. at the edge of the swamp
Posts: 3,836
The problem with using a deadhead type fuel system is, if the pump isn't designed for it, there can be overheating of the pump and that can shorten pump life. A bypass type regulator avoids all this.
One other point, I was informed by Aeromotive to use the same size return as the supply line on a bypass type regulator. I assume this is to prevent fuel pressure creep.

John

The Fauxstang. Dynacorn 67 fastback. Dart SHP 363, Close ratio Magnum 6 speed, 3.70 Eaton Truetrac in a fabricated full floater 9", SorT coil over suspension. Still in pieces.
'14 SHO with most all the bells and whistles. Stock for now.
F-150 SCab daily driver
j persons is offline  
post #7 of 10 (permalink) Old 04-11-2018, 09:27 AM
Moderator
 
HoosierBuddy's Avatar
 
Join Date: Aug 2002
Location: Probably in the garage
Posts: 6,806
So...I did exactly what you're talking about. I ran an intank fuel pump with a carburetor for a season and then switched to EFI using the same system.

I took my feed line all the way to the engine bay where I mounted my FPR on the passenger side fenderwall, just in front of the hood hinge. The return line hooked in there and took all the extra fuel back to the tank. I just had a braided fuel hose from there taking the regulated (5 PSI or less) fuel over to my holley.

THEN...all I had to do was take out the carburetor FPR and plumb over to the EFI FPR at the back of my fuel rails when I changed over to an EFI engine.

I wrote the whole project up for Fordmuscle.com at the time. You can get to at least some of it still here:

In-tank EFI Fuel Pump Modification and Installtion - FordMuscle

Phil



"Two barks means faster!" Enzo
HoosierBuddy is offline  
post #8 of 10 (permalink) Old 04-11-2018, 10:30 AM
Senior Member
 
Join Date: Aug 2010
Location: WNC
Posts: 397
Quote:
Originally Posted by SM94Cobra View Post
I just changed to a dead head set up on my Fitech set up with an Aeromotive in-tank set up. I previously had an external pump with feed and return going directly to and from the TB. I am in NC and I get a lot of heat from my big block set up with it being worse in the summer time, so the fuel was getting hot and would eventually vapor lock on longer drives. I just got the car running with no drive time yet, but it is up and running and I am expecting better results. I plumbed a supply and return line up the passenger side and put the regulator in the passenger side fender well with a deadhead feed directly to the TB. Have right at 60 PSI to the regulator and car runs idles and has good throttle response so far. Hoping to get it on the road this weekend. I tried to keep everything out of the engine bay heat, including the regulator, to avoid sending any heated fuel back to the tank. Trying to keep everything as cool as possible. FiTech has stated that dead head is not a problem as long as you have another regulator in place for fuel that is not used , otherwise it would over power the internal regulator.
Are you sure you're getting vapor lock? It could be a lack of tank venting causing suction.

Generally a dead-headed system will vapor lock easier since you don't get any cooling from the circulation back to the tank. Your dead-headed line is so short it probably won't matter much though.

1968 Mustang Coupe | 331 | T5 | FiTech EFI
jcoby is offline  
post #9 of 10 (permalink) Old 04-11-2018, 11:27 AM
Member
 
SM94Cobra's Avatar
 
Join Date: Feb 2006
Location: Raleigh
Posts: 59
Quote:
Originally Posted by jcoby View Post
Are you sure you're getting vapor lock? It could be a lack of tank venting causing suction.

Generally a dead-headed system will vapor lock easier since you don't get any cooling from the circulation back to the tank. Your dead-headed line is so short it probably won't matter much though.
Yes, 100% vapor lock, no venting issues.

When i said dead head, there is still a return line in the system, with only about a 3 foot section of hose from Regulator to TB. Pump is still constantly running and not using PWM for the pump. Part of the issues that some are seeing is that there is actually heating of the fuel going back to the fuel tank after being heat soaked by the fuel rails and engine compartment. This set up allows for continued circulation with only fuel entering the engine bay being used at the TB.

http://forums.vintage-mustang.com/signaturepics/sigpic30626_12.gif
1969 S Code Mach 1
445 FE Stroker
TKO 600
Street or Track Suspension
SM94Cobra is offline  
post #10 of 10 (permalink) Old 07-21-2018, 03:13 PM Thread Starter
Senior Member
 
Join Date: Oct 2014
Posts: 110
Thanks for all the replies and help. I ended up running a new 3/8 line to the front and used the OE 5/16 as a return. Then a single line from the regulator to the carb. It ran great, but I found a wicked good deal on a Fitech Power adder system. That's installed and also running great on the same fuel system.

I used regular compression fittings everywhere and there were a few leaks that went away with a little extra tightening. Now everything works great.

Thanks again guys

1966 Mustang 302ci 4r70w, csrp front discs, 8.8 rear, EPAS, Fitech for fuel
copracr is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome