LSJ boost referenced fuel system

[95Blitz]

I have been over thinking this boost referenced fuel system for a while now. After looking at OTTP and ZZP systems and reading through ZZP's install, I think I have worked it out. Please check the diagram and make sure I am looking at this correctly. I did leave out the vacuum/boost side of the diagram just to make it easier to read and I know the pump has to come out to remove the regulator.

 

[Rauq]

That looks correct for ZZP's intended application.

There are other ways of doing it, if you're interested.

 

[95Blitz]

That looks correct for ZZP's intended application.

There are other ways of doing it, if you're interested.

Yeah let's see it.

 

[Rauq]

Fuel filter is from a 2004 Colorado. Basically the same filter but with a single barb in and out.
Blue star is OTTP's fuel rail fitting: https://www.overthetopperformance.com/Fuel-Rail-Fitting-LSJ_p_101.html
Green star is CBM's fuel rail fitting: https://store.custombuiltmotors.com/fuel-delivery/cbm-motorsports-22l-24l-ecotec-to--6an-fuel-rail-adapter-no-regulator.html
Red star is a fuel pressure regulator of your choice that connects directly to the CBM fitting

I don't have any pictures of the setup on my car at the moment but the result is a flow-through setup with a regulator mounted at the rail. I 3d printed a little bracket that braces the regulator to a stud on the valve cover.

 

[95Blitz]

I like that setup, wasn't sure if the fittings for the rail were available or not. That's the type setup I have used before but with 2 rails feeding into the regulator.

 

[Rauq]

Yeah it's a little silly to have to pick up multiple specialized fittings from a couple different vendors but I really like the simplicity of the regulator mounted directly to the rail. I read both ways that I would and wouldn't run into issues flowing fuel through the rail in the opposite direction of stock but I didn't see any reason it wouldn't work with the parts in my hand and it's worked well in the year it's been on the car so far. Plus I did it for about half of what ZZP's kit cost.

 

[Tinkles]

View attachment 39248

Fuel filter is from a 2004 Colorado. Basically the same filter but with a single barb in and out.
Blue star is OTTP's fuel rail fitting: https://www.overthetopperformance.com/Fuel-Rail-Fitting-LSJ_p_101.html
Green star is CBM's fuel rail fitting: https://store.custombuiltmotors.com/fuel-delivery/cbm-motorsports-22l-24l-ecotec-to--6an-fuel-rail-adapter-no-regulator.html
Red star is a fuel pressure regulator of your choice that connects directly to the CBM fitting

I don't have any pictures of the setup on my car at the moment but the result is a flow-through setup with a regulator mounted at the rail. I 3d printed a little bracket that braces the regulator to a stud on the valve cover.

I have my fuel system planned out the same way, except for Radium Engineering pumps, filter and an external regulator/pulse damper. My fuel rail is set up with the same fittings.

The stock LSJ fuel rail does decrease slightly in diameter from one end to the other. But with my setup with a -8an feed and -6an return I do not for see any fuel supply issues. I might end up with slightly higher fuel pressure at the #4 injector vs #1 injector, but I am not going to put fuel pressure gauges on each end of the rail to measure something I am not going to change and to potentially only see a ~2psi difference.