I buying a TPI 350 motor. I have an aftermarket computer and the harness as well. Everything at least for what I was told was that this is set up for a plug and play application, 350 HP. So my question is... How do I route the fuel lines? I plan on using an external fuel pump mounted close to the tank. I know many of you prefer an inside tank pump but for ease of installation I am thinking the outside pump would be better.

What kind of lines to I need to run? Also, Does everything need to be hard lined or can I use clamps and hoses? If so where would I run them? Can I use a DOUBLE lined fuel sending unit in the tank and if so how would I run the return line? I guess I am trying to do everything with the fuel system correct since I want to make sure I have a leak free, safe system for this TPI motor. Also where would I run the fuel filter and should I run a regulator?? Sorry for all the questions but I am a EFI newbie.

Thanks In Advance.

Mark

Clamps and hoses are fine as long as they are made for EFI pressures.

Also, company's like Russell and Earls sell compression to AN fittings that will easily attach to 3/8" hardline.

External pumps are a reality for many. I've been told that WalBro makes the best ones. I've had trouble with Bosch, but that was 7 or 8 years ago.

It's best to make the return line the same size as the supply. If the return is smaller, pressure can rise at idle and you'll always be rich.

Best is to drill a hole in the sender plate and braze the return line in.

If you don't have a crossflow muffler, there will be plenty of room in front of the tank. I'd fix a stiff metal plate dropping down from the trunk floor. Mount it in rubber grommets to minimiz noise and vibration.

Fuel needs to go thru the prefilter first, then the pump, then the final filter.
Mount the pump horizontally at about the same level as the bottom of the tank. If it "blows" toward the drivers side of the car, you can loop a hose into the main filter mounted above it, which will then be pointed straight at the frame mounted fuel line.

The regulator is normlly part of the return side of the fuel rails on the intake manifold, no other regulator is needed.

I use in tank pumps because I don't want to ever run out of fuel because of slosh. I suppose if you always keep the tank pretty full you'd be fine.

Fuel lines, I always run dual 3/8 lines. I had right stuff detailing bend me up two stock 67 camaro 3/8 fuel lines with extra length on the front and back. Then I just bent and cut to fit. To connect to the pump I used braided steel hose with AN fittings. They make tube connectors to mate hose to hard line which is what I did. I did the same to connect the hard lines to the fuel rails.

I used an inline Edelbrock fuel filter that had AN fittings.

I'm not sure what kind of setup you're getting, but yes you'll need a pressure regulator. Is there one on the fuel rails with your setup?

The stock two line fuel senders had a 3/8 supply, 1/4 return. The 1/4 return is probably too small and could cause you some issues. Most places that I've talked to recommend at least a 5/16 return.


*** Damn Jim beat me to it!! Sorry for stating the same thing as Jim.

*** Damn Jim beat me to it!! Sorry for stating the same thing as Jim.

Good to see we're on exactly the same page Paul!!

As Paul said you should use a tank with a sump built in and a intank pump , your motor will fall on its face if you don't keep the tank full from the slosh .
Mark.

You can get away with an external pump if you never let the tank get below 1/4 full...

Tanks Inc makes a slick setup to add a sump and in-tank pump to a fuel tank. You need to also get a new $125 repro tank from someone like Ricks, cut out a big square, and weld a small box in it to mount the pump. Here's a guy who did it for a 2nd gen tank: http://www.ls1tech.com/forums/showpost.php?p=4088216&postcount=14

If you want a simple bolt-in and don't mind spending $1100, you can get a brand new stainless steel tank with an in-tank EFI pump from someone like Rock Valley. Here's my Rock Valley tank: http://www.blown.net/ls1swap/DSCF3932.html.

For compression to AN fittings, I prefer Swagelok. You can't order them online--you have to go through a local distributor. These are what I used on 3600psi compressed natural gas lines, and they are without a doubt the best compression fittings made.

You can get away with an external pump if you never let the tank get below 1/4 full....

Why do so many say that?
Can it be true?
The stock pickup will definitely suck the tank dry with a carb.
I ran a Holley TBI once with an external pump in a truck, found out on more than one occasion that the EFI pump would in fact suck the tank dry, and would re-prime again without a problem.

TBI uses a low pressure pump. Supposedly the high pressure pumps burn up quickly when you run 'em dry.

I ran an external pump for a couple of years and could not wait to get rid of it. Even with headers and a loud exhaust you will hear it wine and it will drive you nuts! No problems with 1/4 tank or anything though.

Actually I am either going to modify my OEM tank using a pump and sloush tray from tanks inc or I am gonna use this tank and mount it in the trunk

http://www.tanksinc.com/index.cfm/pa...rod/prd129.htm

Cool thing about this setup is that it will mount from inside the trunk with a lip almost like the half in half out setup except it will only stick up about two inches allowing you to make a false floor to go flush with it and save you trunk space. It also cuts 7 inches off the total width of the tank so if you need the extra wheel room you have it. 16 gallons opposed to the 18 gallon OEM tank. Depth is about the same. Price of the tank is $250 add another $225 for the pump set up and baffle tray and you have a narrowed tank that is set up well for EFI with an in tank pump all for $475... I am seriously looking into doing this instead of modifying my OEM tank. Guess my car will have to be the test vehicle... Anyone see any problems with this????

MARK
TOOFUN

I bought a new repro tank, sent it to rock valley and had them install their pump enclosure. They did a great job. I went with the in tank pump thinking that the factory does it this way and they have few problems with them.
I also ran 3/8 hard line for pressure and return, then braided flex to the fuel rail.