Orange Juice

iTrader: (3)

For those that have a external fuel pressure regulator. Where did you locate it, what did you run for a return fuel line. Steel, braided or just a reinforced rubber gas line. I wouldn't expect the return line wouldn't have to handle that much pressure.
I posted this in the fuel section but I thought I may get more answers in a section where a external FPL would see more use.

Taxman20

iTrader: (11)

I always mount mine under the hood somewhere. I run braided line, but any line rated for the pressure is fine. The return will flow but since its just dumping back into the tank or cell, there really isn't any pressure on it.

slocaddy

I put mine directly on the rail, made a little braket to support it.
I used fragola push lock hose for fuel line.


Braket for support

35spline

iTrader: (1)

Slocaddy, Is your intake the newer returnless style? What fitting (part #) are you using between the fpr and the fuel rail?

Crf450r420

iTrader: (1)

Use these threaded ones and you will never have an issue. The ones with plastic lock like the stock lines pop off on some people.

http://www.summitracing.com/parts/rus-644123/overview/

I'm about to do mine and I'm going to try and cheat. Not sure if it will work, but I'm going to use these fittings and try and use the 5/16" emissions line as my return.

jimmyg

I think the best place for a reg is after the rails. Think about it ,all a reg is is a restriction in the line to keep pressure up. On my build I'm using -8 to the rails, y fitting into -6 to each side of rails, -6 to reg, -6 return .this will insure full volume to injectors. When placed before the rails, the higher the fuel pressure, the lower the volume.

forcd ind

iTrader: (7)

I made a mount 6" off the firewall for the reg, ran a #10 pump to fuel rail, #8 cross over, and back out to reg.-I ran a #8 return-prob over kill for what I have, used reg quality stainless braided
Kind of a crappy picture, lol

slocaddy

yup, it's returnless, they say get it as close to rail as possible, so that's what did lol
Its the same Russell #644123 screw on type

slocaddy

Can't remember if someone males a 5/16 push on barb, but original I was going to do the same thing, except with 3/8.
I ended up just going with an push lock and 1/2 feed line

slocaddy

This is correct.
(But somtimes your motor came with returnless style fuel rails lol)
I'm also using -8 with dual walbros, hopefully it works out for me,
Many have done it before with no issues, however we know this is not "ideal"

roastin240

iTrader: (13)

Run teflon lines not rubber lines. Both have stainless steel outer layer.

3 window

iTrader: (1)

Returnless rails. Flipped the rails around to keep the regulator off/away from the firewall. -10 feed, -8 crossover and return.

Taxman20

iTrader: (11)

I like the idea of running the supply line to each rail separate, or with a Y between the FPR and the rails. I myself am new to the EFI setups, but it seems for a big hp engine with really high flow rates, if you run the rails with 1 supply and then a crossover line for the other rail, you could have some loss of pressure and or flow to the last injector in the series and maybe even before that last one. So with the Y each rail is only supplying 4 injectors instead of the one inlet supplying 8.
Thoughts? Or is this overthinking it?

slocaddy

Not a pro by any means, but I would think if you have enough fuel pressure, it wouldn't be an issue? ?

forcd ind

iTrader: (7)

I thought the same thing until I saw a Nascar engine using the cross over.
If they can survive going 10K RPM's my stuff should survive at 6500, lol

Taxman20

iTrader: (11)

Carbs are completely different and also very low pressure. Usually below 6psi. They do flow well but its only 2 bowls being supplied, not 8 injectors. So the carb does push out a lot of fuel volume equal to the fuel if it were an EFI system. But there is flow loss and pressure loss when you run any length and making turns. Its psychometrics, or pressure and flow loss factors.

Orange Juice

iTrader: (3)

Thanks for the replies. How much of a difference does the boost/vacuum reference make?

3 window

iTrader: (1)

NAPCAR runs EFI now.

Taxman20

iTrader: (11)

Sure do. Lol. I lost interest in NASCAR when they stopped racing. So its been a while.

3 window

iTrader: (1)

I can stand on any overpass and see the same thing! Gas mileage?....restrict plates? What??