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Dual Entry Fuel Rail

75coupe

By 75coupe,
in Engines & Forced Induction

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DCIEVE Mentor

DCIEVE

Posted
Posted

It's very easy to put together braided lines, the only issue as mentioned earlier is any stray wire messes up the thread in the fittings = chop the line and bin the fitting. You'll only do it once.

Twin feed or single, either way I would be tuning with individual EGT. The cost is negligible and they're easily removed once the car is tuned. I have very large corrections, eg the largest trim is -4'ish% to +13% on one cylinder (not 6), depending on manifold pressure.

scotty nm35 Grand Master

scotty nm35

Posted
Posted

How accurate are the sensors? There would be a discrepancy between them too right? What unit do you use to read/log the temps and what do you plug the hole with when you are finished? I guess there is variation with injector flow if the tune is out that much between cylinders...

I have a V6 so twin rails. I just finished making a twin Walbro intank setup with -6 lines to each rail, I didn't want issues with one pump failing and not knowing so this way, and with 2 one way valves before the reg, I can separate the flow to each rail completely. That way 3 injectors will fail completely if one pump goes. I will only have one return from the reg though. All teflon lines as i'm running Eflex.

post-63525-0-24862300-1302492512_thumb.jpg

Nee-san Grand Master

Nee-san

Posted
Posted

The idea is to eliminate pressure drop yes, but the actual problem is transience between individual cylinder fuel pressure etc.

twin entry rail goes some way to making this problem better.

obviously you dont have a hugely diminishing fuel pressure over the length of the rail, as the FPR controls the global rail pressure (to a degree).

DCIEVE Mentor

DCIEVE

Posted
Posted

How accurate are the sensors? There would be a discrepancy between them too right? What unit do you use to read/log the temps and what do you plug the hole with when you are finished? I guess there is variation with injector flow if the tune is out that much between cylinders...

The thermocouples are accurate to within a couple of degrees - far more accurate than required. Plugging the hole is easy using a bung. There are plenty of cheap logging options but I was using Innovate gear.

The injectors tested within a couple percent before installing, and a second motor with a completely different set-up (not my car) had near on identical results with different logging gear.

I would encourage any modifier to find out for themselves, cheap insurance and far better than relying on (untested) forum theory to tell you where to stick your highest flowing injector.

  • 5 months later...
Beer Baron Grand Master

Beer Baron

Posted
Posted

it's a piece of cake mate. remove the current fuel line between fuel filter and rail. now put on a new shorter line which feeds a Y piece (into the bottom of the Y). to the top of the Y you add 2 new fuel lines, run one to the back of the rail and one to the front. if you are really pedantic try and keep them the same length. then mount the reg on the drivers side strut tower, run a new reg feed from the middle port on the fuel rail, then return from the bottom of the reg into the fuel return line back to tank. easy. can use dash fittings and braided hose if you like, or otherwise just normal hose barbs and 8mm fuel hose with fuel hose clamps is fine too.

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