EFI fuel system questions

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Eric Z.

n00b
May 12, 2012
4
0
0
HI am converting from stock 305 4bbl over to a built 383 with an Terminator EFI setup from Holley. I'm estimating approx. 425-450 hp from it. I need help choosing a fuel system for it. So far I'm thinking of going with a new Buick GN gas tank from ebay and an in tank assembly from Racetronix with either a 255lph or 304lph in tank pump.
My questions are:

What size feed line and return line should I go with?

What type of FP regulator would I want to use?

Any thoughts about the in tank setup I'm looking at vs. an inline fuel pump setup?

Does anyone have a wire diagram that I could use to wire the pump on a relay setup?

Any other input is appreciated.

Thanks!
 

dogsht

Royal Smart Person
Nov 11, 2008
2,003
9
36
Dayton, OH
3/8 & 3/8th
Return style. I used Mallory 4309
What you doing is far better than an inline fuel pump setup. Quiet, always cold fuel from tank, factory reliable, stealth.
Racetronix used to have a diagram.. Maybe text them. Also www.gnttype.org I believe has/had one.
 

85olds

Not-quite-so-new-guy
Oct 1, 2013
35
2
0
A in tank pump is a better system then the in line pump I am using ( on really hot days after a long drive) the pump starts humming. I have gone through 3 pumps since 2001 since I put a fuel cooler on the return line this year I think I have only heard the pump twice this year.

An adjustable fuel regulater would be a good idea so you can fine tune fuel management easer. Are you installing a wide ban o2 sensor and gauge?

When you get the EFI kit it should give you proper wiring diagrams and relays...if racing I would make sure to use a separate oil pressure switch to control the fuel pump relay , when you loose oil press you loose fuel press as well..(racing guys may help with this better then me) you will just need have something to first prime the system when the key is turned on so you don't have to crank the engine over for a long time. (I would hope the EFI kit would incorporate this) I am using a stock gm computer for my TPI setup

And yes I agree with previous post 3/8 supply and return...many make the mistake of down sizing the return line because it is cheaper but you do not want to restrict the fuel returning it will mess with the fuel reg pressure and tuning normally at idle.

Hope some of this helps....all is from my personal experience on tuning my car which is nowhere near stock anymore
 

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Eric Z.

n00b
May 12, 2012
4
0
0
dogshit said:
3/8 & 3/8th
Return style. I used Mallory 4309
What you doing is far better than an inline fuel pump setup. Quiet, always cold fuel from tank, factory reliable, stealth.
Racetronix used to have a diagram.. Maybe text them. Also http://www.gnttype.org I believe has/had one.

Cool, I was thinking -6an would probably be what I wanted to use. Racetronix used to also have a plug n play harness on their sight that would have worked with my car (86 GP) but I can’t find it now.
82Calais said:
Did you price your tank at Rock Auto? Wondering what the price difference was?
I just did, rock auto seems to be cheaper. I wonder what the differences between the aftermarket tanks. Spectra seems to be the pricier of all I have looked at, I don’t mind paying extra if the tank is a better quality.
85olds said:
Are you installing a wide ban o2 sensor and gauge?
I will be installing the wideband that comes with the kit.

85olds said:
When you get the EFI kit it should give you proper wiring diagrams and relays...if racing I would make sure to use a separate oil pressure switch to control the fuel pump relay , when you loose oil press you loose fuel press as well..(racing guys may help with this better then me) you will just need have something to first prime the system when the key is turned on so you don't have to crank the engine over for a long time. (I would hope the EFI kit would incorporate this) I am using a stock gm computer for my TPI setup
I have been reading the install manual and it does appear to have a connection in the supplied harness for a fuel pump. There isn’t a relay included though from what I can tell. I won’t be doing much racing. I will use it 99% for street fun. The oil pressure switch might not be a bad idea anyways. Cool set up you have there. Love the way the TPI looks with the blower.
 

85olds

Not-quite-so-new-guy
Oct 1, 2013
35
2
0
Adding a relay is a good idea then just to protect the computer from if the pump or wiring if it ever screws up. And also it does not send electrical noise (feedback) back to the computer.

Adding the extra wide ban gauge inside the car was the best thing I ever did...know I can see exactly what the fuel is doing at idle and full out.

I drive mine all summer long and the ocasinal track visit, my friend has a 12.2 second camaro with a 502 in it and I can beat him just barely. And use less than 1/2 the fuel he does..(love the fuel injection)
 

crucial118

Royal Smart Person
Nov 15, 2008
1,055
51
48
MARYLAND, DMV
Be careful of the grand national tank off ebay. I got mine from a seller on ebay a while back, because of the appealing price tag, and the spot welds that hold the baffles in the tank cracked from underneath and started to seep gasoline. I would spend a little more and get a quality one from opgi, year one, or some place like that. You only want to do a gas tank swap once.
 

Eric Z.

n00b
May 12, 2012
4
0
0
85olds said:
Adding a relay is a good idea then just to protect the computer from if the pump or wiring if it ever screws up. And also it does not send electrical noise (feedback) back to the computer.

Adding the extra wide ban gauge inside the car was the best thing I ever did...know I can see exactly what the fuel is doing at idle and full out.

I’ll plan on both.

crucial118 said:
Be careful of the grand national tank off ebay. I got mine from a seller on ebay a while back, because of the appealing price tag, and the spot welds that hold the baffles in the tank cracked from underneath and started to seep gasoline. I would spend a little more and get a quality one from opgi, year one, or some place like that. You only want to do a gas tank swap once.

The ones that OPG and year one carry are actually cheaper than Rock auto and ebay… lol wish there was a way to definitively know which is best…

Thanks for all the input and feedback everyone!
 

Chuck Leeper

Not-quite-so-new-guy
May 9, 2013
5
0
0
Atlanta, GA.
Late getting in on this...
Just got my GN tank from Bob's Impalas, in AZ. $122.00 including the ride.
It's the latest Spectra design. [They make A LOT of OEM tanks, and have a good rep w/ the Buick crowd.]
The tank has the baffles in it, is very well prepped and coated. Well packaged, too.
 
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