Re: Help with fuel system design for LS1 install
 

Been thinking about going with and 5.3 and been thinking about all the costs that I will need to do the swap. I have an 83 with dual tanks. Can I use everything I currently have and just hook an external pump to them? They won't have baffles like FI tanks have is that ok? Also all of the rubber lines that are currently there will need to be replaced? Can the stock tank selector valve handle the pressure or is it just "presurized" after the pump?

Thanks in advnaced! I'm a newb!

Re: Help with fuel system design for LS1 install
 

I was doing some reading about fuel pumps and pressures and come across this on another forum. Thought I'd share if it's not already here somewhere.

Here is a little fuel pump tech…..

Just a little background. I’m installing a 2004 5.3 in a 9 GMC Sierra. When the fuel pump question came up I read that you needed to use a Delco EP241. To double check this I called S&P and they said also to use a EP241. Just for giggles ( after I installed the EP241 in the tank and truck ), I checked the specs on these pumps. Now what I got were specs from Airtex book where I work at Carquest.

EP241 ( E3210 Airtex) = Flow= 40 gph & PSI = 65-75
Now that pressure reading is right on the head of the pump at the lab and if you take into account filters and lines and lengths, it’ll probably equate to 50-55 psi… should be.

I wasn’t to impressed with those # and did some checking. I went up in years and found the EP381 pump used in the early vortec trucks, cyclones, ect….and here are it’s #’s

EP381 (E3270 Airtex) = Flow = 50-60 GPH & PSI = 80-90
Here again that psi rating is under perfect conditions at the lab and on the head of the pump. It should yield you a 70-80psi in the vehicle.

I called Airtex and talked to their guy Craig there. He confirmed these numbers I have here and inquired what I was working on. I told him and he said.. quote “ you should never use a EP241 on a vortec or LS1 motor” Craig went on to explain that it would work but the pump would be working itself to death to maintain the pressure and that would shorten the lifespan dramatically. He also explained that the EP381’s were manufactured with a new thin magnet design which yielded a lot higher torque that the EP241’s. They were specifically designed to work on Vortec & LS1 style engines. Also he said the current draw on the EP380 would be significantly less than the EP241, less current = less heat=longer life.
The EP241 is designed to work with TPI & MPI and should only be used in this application

I had my pump out fixing a split hose anyway so I went ahead and got the EP381, well our Airtex E3270.

Just wanted to pass along this little tid-bit of information. I know you guys with newer trucks already have high flow high pressure pumps in the tanks from the factory. But maybe this will help others with their modifications.

Re: Help with fuel system design for LS1 install
 

I'm new to this forum, but I've been reading the different post for a couple weeks now trying to figure out what year, make, model truck or car gas tank will fit under the bed of my 67 gmc swb truck. I'm in the process of installing a 5.3 from a 03 chevy avalanche. this is my first time trying to do something like this, so all and any help you guys can give me would be GREATLY APPRECIATED!!!!!!!!!!!

Re: Help with fuel system design for LS1 install
 

Steel braided Teflon line with steel 37* fittings drilled and silver soldered to the fuel rail and tank sending unit for the 87 fuel sender, stock fuel filter with steel fittings silver soldered. the tank is a Dorman tank for a 87 short bed

Re: Help with fuel system design for LS1 install
 

thanks i was dead in da water, do u know if the digital dash that lmc offer will work with a 4l60e transmission or will i still have to buy the cable x to make da speedo work

Re: Help with fuel system design for LS1 install
 

Is this the return style fuel system?

http://i42.tinypic.com/1036ej7.jpg

Re: Help with fuel system design for LS1 install
 

BUMP. I've got the same question LLS10

Re: Help with fuel system design for LS1 install
 

No the black hose sucks fuel vapors from the tank for emissions

Re: Help with fuel system design for LS1 install
 

Thanks CC. This eliminates one thing out of the fuel enigma.

Re: Help with fuel system design for LS1 install
 

Hey Guys,

i also ordered a 06 LQ4 to swap it into my 1797 Suburban.
The Seller told me that i have the Rail System with the Return Line, so no Vette Filter.
Should i use filter before or after the 255 Walbro?
Does anybody of you know what size and type of connections a 79 Fuel Tank has?
Does this Fuel Tank have a Connection for a return line?

Greets From Austria :-)

Re: Help with fuel system design for LS1 install
 

damn, that's an oldie! didn't know Napoleon was a GM guy!

Re: Help with fuel system design for LS1 install
 

2006 seems awful late to still have a return style fuel rail. Your '79 tank will just have hose pushed on the sender and clamped. If you are planning to run an external fuel pump, it would be in your best interest to use some kind of a pre filter to keep any junk out of the pump. People have run them without a filter, but you are taking a chance, and if it's worth doing, in my opinion I would do it once and be done with it. That said, your even better option would be to get a '87 tank and sender and put a Walbro 255 pump in the tank. That is if an '87 tank will fit a 1797 Suburban. :lol: Pretty sure you meant 1979?

Re: Help with fuel system design for LS1 install
 

Hahahaha yes Napoleon was a Chevy Guy, thats why he called himself an Imperator :D
no just mistake, it's an 1979 ;-) According the seller is has the fuel rail with the return line, the engine will arrive end of January here.
The idea with the 87 tank is nice, but it's hard to get one here in Europe, so i want to use the Russell 650133 Filter before the Pump, so there can be nothing damaged by junk, is that possible?

Re: Help with fuel system design for LS1 install
 

Guess you'll just have to wait and see when it shows up on whether or not its a returnless rail, but if it isn't I would be suspect om the year of the engine. Also a 40 micron filter may be a little too restrictive. Ideally you would want around a 100 micron filter. Heres what I've used in the past, work well and reasonably priced, but not sure what shipping to Austria would do to the savings. http://www.robbmcperformance.com/products/filters.html

Re: Help with fuel system design for LS1 install
 

I read everyone talking about this "87 tank". What GM/Chevy model are you folks referring to? What's so special or unique about this tank, and why an '87 only?

Thanks in advance.

My build:
'82 K10 4x4.
Short bed with 350/700R4

Swapping in an '05 CTS-V LS6.

Re: Help with fuel system design for LS1 install
 

1987 Chevy truck. Its a bolt in tank for '73-'87 trucks, but sinceGM switched to fuel injection in '87, its set up for an in tank pump with the correct baffling to keep starvation issues at a minimum.

Re: Help with fuel system design for LS1 install
 

That's awesome

Thanks LS1Nova.

So I can pick one up from RockAuto specifically made for the R/V series '87 trucks and that's wah-la?

Re: Help with fuel system design for LS1 install
 

I think it's not wah-la, you have to change the pump in the Tank, but there are some kits on the market, Walbro etc.. i think the the 87 Pump won't bring enough pressure for your injection system.
Thanks LS1 Nova for the Link to the Filter!

Re: Help with fuel system design for LS1 install
 

Haha "wah-la". Yea I knew I'd be needing a better pump than what was offered in 87. I wish I had a part number so there wouldn't be a doubt about what tanks I exactly need. Thanks for all the help. I've been reading a whole lot on this swap sub forum and I have gained lots of knowledge.

Re: Help with fuel system design for LS1 install
 

Merle's has them on the shelf, sending units for a 87 also and a fuel pump for a 2002 Camaro and ready too go !!

Re: Help with fuel system design for LS1 install
 

Now that I have to look into.

Re: Help with fuel system design for LS1 install
 

does the 381 fit directly into a 87-91 efi tank? would i use a 87 hanger assembly?im putting a 5.3 lm7 into my 86 k5.thanks!!!

Re: Help with fuel system design for LS1 install
 

It will fit a factory 87-up sender, but do yourself a favor and don't buy an Airtex unless your idea of a good time is dropping a fuel tank to replace a dead pump. Been there a few too many times.

Re: Help with fuel system design for LS1 install
 

any updates?

Re: Help with fuel system design for LS1 install
 

How about a Walbro 400? I don't need it now but plan on going FI in the future and would like the headroom.