Ls2 fuel rails

[Bow tie downunder]

I have a ls2 and the fuel rails have 1 inlet line .I need a return line back to the tank . I am looking at tig welding a fitting to the rails for the return line .Is there a better way to do this .
Mick

[rockytopper R.I.P 5-13-2017]

You don't want to do that. You will need a vet filter regulator to keep a constant 58 psi on the rail. The filter/regulator has a return line in it. You should mount it near the fuel tank as possible.
Rocky

[Bow tie downunder]

Thanks for the advice ,could you please post a sketch a the fuel line .I understand the need for a filter regulator,but I m not sure about the return line.

[Rick_L]

bowtiedownunder, Chevy has done it two ways over the years, and both seem to work.

Initially the LS1s had the pressure regulator mounted on the fuel rail, and there was a return line on the regulator to return the unused fuel. Sometime in the early 00s, they went to the pressure regulator near the tank. Again there is a return line on the regulator, with a short run back to the tank. This was before the LS2 came out, and it used the same setup. The Corvette regulator/filter is the one usually used, as it's compact and relatively cheap.

The fuel rails without a regulator/return line are much easier to deal with, as you don't need a return line that's the full length of the car.

[rockytopper R.I.P 5-13-2017]

Here is a link to the filter regulator.
https://www.bing.com/images/search?q=corvette+fuel+filter+regulator&qpvt=corvette+fuel+filter+regulator&qpvt=corvette+fuel+filter+regulator&qpvt=corvette+fuel+filter+regulator&FORM=IGRE

[WagonCrazy]

Mick,
I have a 2002 LS1 in my Nomad. It has a single line fuel rail as Rick mentions above. I installed a new TanksInc tank made with an in-tank pump and plumbed in the Corvette style filter regulator just forward of the tank (mounted on the inside of the passenger frame rail).

Looks like this...

5977

5976

[chevynut]

I guess I'm one who likes to see the regulator at the fuel rail. Injector fuel flow is sensitive to pressure, so how does the regulator being near the tank compensate for pressure losses between it and the tank? Maybe they figure that with the higher pressure it doesn't matter as much? It makes me wonder why they don't just incorporate a regulator into the pump itself.

Also as I understand it not all LS engines used this "returnless" Corvette system so if you use it do you need to change the fuel map? Seems like you'd need to know what the ECM is set up for.

[NickP]

Be it a matter of economics or improved components, both seem to have worked for GM. My preference is at the rear if for no other reason than to eliminate an additional line, fittings, clamps and time.

http://pic20.picturetrail.com/VOL1600/2283636/23877721/405578889.jpg

[Rick_L]

Theoretically, having the regulator on the fuel rail should result in less pressure fluctuation.

I think the higher fuel pressure of the LS engines (4 bar or 58 psi) is helpful in overcoming this, relative to earlier setups that are 3 bar/43 psi or even less.

As Nick said, they figured out that they could get away with it, and in the process reduce some cost and complexity.

The fuel map does change with varying fuel pressure, since an injector's flow is proportional to pressure. In fact that's a potential tuning tool - you can richen or lean the engine by changing the fuel pressure. Some pressure regulators even utilize that - having a vacuum operated diaphragm that lowers the fuel pressure 5 psi or so when engine vacuum is high.

There are also GM fuel systems with pulse width modulated voltage to the fuel pump.

[Bow tie downunder]

Thanks everyone for your input,the link and photos are a big help .There are some filter regulators on eBay that will ship to Australia

[rustay56]

Not sure which regulator you are purchasing but some AC Delco regs are actually Wix regs in AC boxes at twice the price. Some people have had problems with Wix maintaining correct pressure.
Regards Andrew