Considering I would convert the 350'z system over to return style, keeping the fuel feed portion unmodified (except for pump and injectors) how much HP would you guys estimate the system could handle?? From a fuel flow perspective of course.

 

the only way you could really do that is to weld outlets on the front of the stock rails... if you did this, i would think you are good for maybe 450-500rwhp. the thing i would question the most is the factory fuel rail feed pipes, they are pretty small! Otherwise I am sure the stock stuff could be used for some decent power, but you might want to put a fuel pressure sensor AFTER the fuel rails to make sure the pressure isnt falling off for the front injectors.

if you have the means, i would recommend an entire return system.

 

Hey phunk,
That's exactly what was thinking of doing, in terms of tapping the ends for AN fittings.

I guess I was just questioning a possible restriction because of the dampners and that funky crossover feed tube. Tapping the other end of the rail could be option as well and feed both rails.

 

if you are set on using the stock rails, i would recommend at least welding AN in/out on each end of them both. The stock rails are pretty restrictive because each of the injector boss' that are soldierd on there actually completely protrude into the rail pipe, blocking more then half of it... thats more than enough restriction, definatly at least feed them with new lines rather then that one small pipe.

 

IMO you're better off getting something that has been designed well, is heavy duty, and has been already running in people's cars for awhile with no issues.

I have the CJM fuel system. I don't have it on my car yet, but HOLY CRAP this thing is heavy duty. You won't be disappointed if you were to get one.

 

heres what i did. i welded on 4- 3/8 inch male pipe thread fittings that accept 3/8 female hose barbs. the oringinal inlets are resticted on the stock fuel rails so you will need to drill them out, but once you do it will be the same inside dia all the way through. on mine the fuel feeds from the rear and exits in the front and i left the rear crossover intact. i used an inline walbro 255, and wired it off a relay from the stock fuel pump signal. a good pressure regulator and return line is all that is needed at that point.
this system is redundant also, meaning if you lose one pump you will not be stranded as they will flow through eachother. no other stock fuel pump or fpr mods are needed and i never get the 1/4 tank fuel shortage some get with aftermarket pump mods. the stock pump just feeds the walbro creating tons of fuel delivery and the stock fpr never closes. i have been using this for about 4 months with not a single flaw or delivery problem.

 

overZealous1, mind if you do a write-up for us DIY guys. =)

 

i don't have many more pics of the return fuel system install but the rest is fairily easy. the inline fuel pump is powered from the fuel pump fuse (right where the battery is located) from the fused side of the fuse. this will still shut both pumps off if you have a roll over. just head to an auto parts place and pick up a standard relay and it will come with the wiring diagram. from that you just tap power from the battery and all wiring is kept inside the same compartment as the battery except for the wires going to the new inline pump.
i went to a local hydraulic hose company and they set me up with some really good 3/8" fuel compatible hose that is rated for heat and about 200-300 psi. if i can remember correctly, once you pull the old connector off from the original fuel line at the pump, 5/16" line will work perfectly off that nipple, just double clamp it to be sure it doesn't leak. once you get to the inline pump, upgrade the pump OUT line to the 3/8". and continue that to a good Y to split it into 2 lines, one to feed each side of the fuel rails. there is a spot under the car right next to the trans on the passenger side that has a cover over it. there is nothing under that cover and the walbro inline 255 pump fits perfectly in there and allows you to run the feed and return line down through the trans tunnel and away from the exhaust entirely.
just get a bulkhead fitting and drill a hole in the top of the pump housing, this will be your return to the tank.
if you know how a return system is supposed to work, all of this is pretty simple and most should be able to figure out what i don't have written here or pictured. i had a total cost of about $350 for all the parts, and this system should support huge amounts of hp because of using the double pumps and not having any scavenge problems either.
btw- the male 3/8" fittings that weld to the stock fuel rails need to be steel in order to weld them on. you can also drill the fittings out a little on the inside to match the outside dia. of the stock fuel rails and get a good pressure fit first, making it easier to weld them on.

 

btw- all the brass fittings are available at home depot (they are all going to be 3/8" u.s. pipe thread with 3/8"nipple) minus the ones you will weld to the fuel lines, which will all be 3/8" male pipe thread, those are hard to find in steel but i was able to find those and the trick aeroquip Y at the same hydraulic line company that i got the fuel line. if anyone wants the big pics, i will have to email them to ya.

 

Very good its similar to how i want to do mine

 

I plan on going with a similar setup. We're going to be doing this for much less than the aftermarket fuel systems.

As soon as I see some more UTEC feedback and decide on an ems, it's ON.

 

oZ1,
As always thanks for the input. Good idea using the inline pump!! I was trying to figure a way to leave the stcok pump system unmolested and all I could come up with was feeding a surge tank which in turn would feed an inline pump. Didn't think about feeding the inline pump directly.. This may the way to go. Are you using an inline filter as well??

 

no inline filter, just the stock fuel sock is it.

 

How about ditching the metal tube that connects the two rails? Will this help with flow?

 

if you decide to go this route, do not ditch it. it can help with any pressure equalization issues. and it really doesn't need to go for any reason either. if you are not comfortable with building your own system, or know exactly what you are trying to achieve, i would suggest going for one of the kits that are available. phunk has some good stuff. my system is a one off fabed set up. if you know your stuff and easy access to a welder, follow my route. if not grab a kit and make life easy, lol.