Returnless LSA vs. GN Fuel system?

[Nick Micale]

Along with the LSA crate engine, the owner supplied a Racetronic's double pumper system with lines and other parts for his GN conversion.

Since this is my first venture dealing with 21st. century automotive technology, the LSA is set up for a returnless fuel system, and I hope someone can give me some direction of how to proceed as I do not think the Racetronics unit is compatible using regular Walbro 340 pumps which are made for a return line?

Also, I am not convinced we should we these 2 pumps at the 700-800 HP level on e-85?

Comments will be appreciated before I proceed further, thanks.

 

[turbo89]

Along with the LSA crate engine, the owner supplied a Racetronic's double pumper system with lines and other parts for his GN conversion.

Since this is my first venture dealing with 21st. century automotive technology, the LSA is set up for a returnless fuel system, and I hope someone can give me some direction of how to proceed as I do not think the Racetronics unit is compatible using regular Walbro 340 pumps which are made for a return line?

Also, I am not convinced we should we these 2 pumps at the 700-800 HP level on e-85?

Comments will be appreciated before I proceed further, thanks.

What are you using to tune with ?

Make it easy on yourself ... just convert it to a return style.. easier ... simpler .. cheaper

 

[20psiofevil]

x2 what are you tuning with?

I hate dealing with my returnless fuel system. 2 255's from high flow fuel, 2 driver modules 1 for each pump, 8g wire to both pumps as well. Over 500rwhp on pump gas and fpdc was high 70's low 80's without a boost a pump. Return the fuel, make your life easier.

 

[Mike E]

The LS system is not exactly a returnless system. It returns through a regulator that is not boost referenced. It's just set at 60psi all the time regardless of vacuum or boost. From the factory a vette had a filter that had a built in 60 psi regulator. A 3rd gen f-body had something built into the fuel sending unit assembly.

You can use the racetronix pumps and run them to a regulator set a 60 psi and feed the rail from there. Now whether or not it's enough to feed the motor is beyond my knowledge.

On a ford returnless system, the pumps are regulated via pwm to control pressure and they have a pressure sensor on the fuel rail. The LS runs the pumps at full speed all the time, it just has a return back at the tank and is not boost referenced.

 

[Nick Micale]

My thinking was to replace the rails with a remote fuel regulator, and use a Hobbs switch for the second pump as this will be mainly a street car and never see the track.

The computer and wiring harness came with the engine from GM.

 

[Sharp86t6]

My thinking was to replace the rails with a remote fuel regulator, and use a Hobbs switch for the second pump as this will be mainly a street car and never see the track.

The computer and wiring harness came with the engine from GM.

That's the way mine is set up. I have the Racetronix dual 340's with hob switch. Running there teflon 8an, holley fuel rails,and regulator.

 

[Chuck Leeper]

Some "observations"....
Looks like an E67 ecm, that can be tuned w/ EFILIVE.
The fuel system would be best "served" w/ the aftermkt rails, return fpr, boost referenced.
Could run into "issues" w/ using the MAF, considering you said you were adding a turbo on top of the blower.
Since E85 is in the program, I'd do some "reverse engineering" and calculate what fuel is needed, based on projected FWHP.
We've not tried a COS, [custom op system], in an E40. However, doing so will run the engine in speed density, and somewhat simplify the tuning and air intake plumbing. [Touching the tune voids the GM warranty.]
More times than not, the "factory" harnesses we get in the shop are so far "off" from what the user wants, we make new. I've not seen the LSA harness, but I'll bet it's a ways from being a good fit.

My $02: I'd return that "install kit", buy the Holley Dominator system w/ unterminated harness, and do away w/ MANY headaches. [Putting one in my 86.]

Back under my rock...

 

[HighPSI]

I have a fuel pressure control module and many other parts for the stock ecu if you need one. If you are considering E85 there are some nice plug and play flex fuel setups out there for the e67 ecu.

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[bigmandengo]

There is no reason to replace the factory rails. Just run a return style regulator between the fuel sender and the rails.

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[SFI Cutlass]

lots of good info here http://www.vaporworx.com