Fuel supply for TPI

[Art Jett]

I am going to be running a TPI system on my '77 and I'm not sure if the electric fuel pump will be able to supply enough fuel if it is getting its supply from the small line that used to supply the mechanical fuel pump. I have the tank out, so if there is a mod I can do to it to help would someone chime in please? I am planning on mounting the elec. pump near the tank and running a 3/8" I.D. hose ( I work at a place that does a lot of hydraulics so I can make just about any hose I need ) to the engine. Also, where do I run the return? It's been a lot of years since I've done any major work on a car, so I am going to bug ya'll a lot. Sorry in advance!
Art

 

[patsnitrovette]

you should use a 3/8 feed line and 5/16 minimum return line.

 

[bossvette]

When I put my TPI in my 76 I used an intank pump from Rock Valley Antiques I ran a new 3/8 line for the supply and used the old 3/8 line as a return. I used a new tank from an earlier year without a bladder

this shows the modified tank with the in tank pump.

 

[mrvette]

Being Lazy....

When I did my TPI in my '72 I just put an 60 bux AZ pump on the frame rail next to the stock 3/8 line location, ran the hoses on either end, and used the stock 1/4 inch line as a return line....if you put a pressure gauge on it, and run the pump, you will find that return line is fine....it handles anything the fuel pressure regulator sets it to.....

been that way for over ten years now....

I used the stock fuel float assy also....easier...only thing is, when the tank gets to about a gallon or so in the bottom, rounding a corner in quick fashion can kill the engine, or cause a stumble....fuel slosh, I never did fix that problem....hell with it, too much work....

GENE

 

[KANE]

I am going to be running a TPI system on my '77 and I'm not sure if the electric fuel pump will be able to supply enough fuel if it is getting its supply from the small line that used to supply the mechanical fuel pump. I have the tank out, so if there is a mod I can do to it to help would someone chime in please? I am planning on mounting the elec. pump near the tank and running a 3/8" I.D. hose ( I work at a place that does a lot of hydraulics so I can make just about any hose I need ) to the engine. Also, where do I run the return? It's been a lot of years since I've done any major work on a car, so I am going to bug ya'll a lot. Sorry in advance!
Art

I used the original 3/8's line and mounted the pump next to the tank. I used the original return line for the TPI too. I thought it was easier that way.

http://www.geocities.com/chiphihawk/

 

[Art Jett]

Thanks! As I said, I haven't done any serious work on a car in about 25 or 30 years and I'll be asking for a lot of help. Getting ready for a business trip tp Angpla for about 3 weeks and upon return I hope to have enough money to order my block and heads. Progress-what a concept!

 

[bossvette]

..only thing is, when the tank gets to about a gallon or so in the bottom, rounding a corner in quick fashion can kill the engine, or cause a stumble....fuel slosh, I never did fix that problem....hell with it, too much work....

GENE

that is one problem with an out of tank pump, the newer tanks are baffelled to control the fuel around the pick-up, my in tank pump is in a canister to keep fuel at the pick-up hence the high dollar price

old fashoned carbs have the fuel bowl to correct fuel starvation, the OEMs just moved it to the tank (baffels)

a work around for using the stock tank(unbaffelled) is to use a low pressure (1 lb) pump to a surge tank then to the high pressure inline pump that is what I am doing on my Old Yellow truck

the small red box is about 2x3x3 and has 4 fittings in it and holds enough fuel to keep the high pressure inline pump going when hard cornering

here you can see both pumps the smaller one is a solenoid pump (low pressure) it fills the surge tank which feeds the inline high pressure pump there is a return from the TPI to the surge tank and a return to the main tank from the surge tank to complete the fuel circut.

 

[mrvette]

I have been thinking of something along those lines myself, that small storage tank under the main tank, but have not found anyting cheap and secure enough to give it a try....kinda scared of failure....what source did you use for the small tank??

GENE

 

[bossvette]

I made it out of 1/8 Cold rolled steel and a co-worker tig welded it the bungs for the fittings were CRS also I have seen them in Aluminum on others cars, but that was too fancy for me. Any good welding or sheet metal shop should be able to fab one up for you . You must have four fittings in it; I got the specs from the "Chevrolet TPI &TBI engine swapping" book by JTR publishing best $30 bucks I spent on the swap. :L it has part numbers for the pumps and all knids of info.

 

[mrvette]

BossV, I am seeing I think fairly clearly what appears to be 4 fittings in and out of that little storage/plenum there, so ok, one in 3/8, one out 3/8, one return from the TPI, fine.....what is the 4th one for??

GENE

 

[bossvette]

you must have 4 lines for it to work properly there is also a return to the tank to keep it from building up any pressure in the surge tank.

 

[mrvette]

you must have 4 lines for it to work properly there is also a return to the tank to keep it from building up any pressure in the surge tank.

OK, one in, one out, one return to the small holding tank from the TPI, and then from the small tank to the top of the main tank??

I did something similar some time ago, using a small plenum to get the fuel return line into the feed line of the fuel pump....and the fule pump insisted on growling somehting FIERCE, made a hell of a racket, but hte engine ran fine....never skipped a beat, but I figgered the pump was not happy, so did away with that kludge fairly quickly....but IF I had a line from my tiney plenum to the main tank you are saying the fuel pressures would have somehow made the pump happy???

stange to me, but oh well, IF that's so....

GENE

 

[bossvette]

According to the book I used the surge tank can't have any pressure build-up, hence the return to the main tank the surge tank is fed by a low pressure pump (AC-Delco EP42S) they also stressed that if you don't have all four lines into the tank it will not work properly. I have not run this as yet as it is on my Yellow Truck and Its not finished yet

 

[Tyler Townsley]

For those of you converting an old style carb system here is a pump that can do carb or EFI on a returnless setup. Claims to be good to 1000+hp.
http://www.racepumps.com/tech.html
http://www.racepumps.com/features.html

Tyler