Series to Parallel Fuel Rails (Cheap DIY Mod)

[SubyFr3ak]

I don't know how many people on here have RS' but I'll do a walk through of how to change your fuel rails from series to parallel so you don't run cylinder 4 lean if you decide to go with more power or turbo (I blew 2 motors *caugh caugh*) but anywho. I'll post pics and stuff as I go along.

[Bu11dogg2]

sweet!

[FREAK]

uh huh interesting

[Murphy2012]

Stuck for future awesomeness!

[SubyFr3ak]

Haha, thanks... I'll have to get pictures and stuff up in a little while when it gets warmer cause I still need to install them on the car, lol.

[Murphy2012]

Ya, please take pics and make a good write up for us. We are all interested!

[Evoeater]

Pull it into a garage and do it!! I want pics!!

[SubyFr3ak]

I'm thinking Feb. vacation that way I have enough down time to make sure its done right.

[RCKSTR]

what are you doing for the fpr? I'm doing this mod aswell, I've got 2 of the complete oem wrx fuel rails to work with and yes, I'm also a DIY whore:D let me know if you've made any progress!!!

http://www.newenglandsubarus.com/forums/showthread.php?t=4408

[SubyFr3ak]

what are you doing for the fpr? I'm doing this mod aswell, I've got 2 of the complete oem wrx fuel rails to work with and yes, I'm also a DIY whore:D let me know if you've made any progress!!!

http://www.newenglandsubarus.com/forums/showthread.php?t=4408

I'm just using the stock one for right now, its mostly just cutting off the one thats on there and moving it up the chain a little ways. There is a diy on scoobymods.com, but I'm going to do mine a little more through.

[Murphy2012]

I hope you are taking pics and planning on making this a worthwhile thread! I stickied it for you!

[Robk0000]

running things in series, wouldnt that give you max pressure on the first device, lower pressure on the second and so fourth?

Do you mean series to parallel? or am i just confusing this royally

[Nate8409]

As it stands the Subaru fuel system is a series. One line in and one out. She is talking about wanting to change to a feed to each rail and a return for each rail. Each rail would have it's own fuel feed splitting the main feed somewhere and then merging the two returns somewhere back into one to the tank.

Nothing too complicated about it. As for us WRX guys there are kits out there you can just buy to accomplish this although the gain in my opinion is minimal if any.

So you keep running #4 lean?

[Murphy2012]

Its a he, and +1 to what Nate said.

[SubyFr3ak]

Yeah there are kits out there for the WRX guys, but I've heard its kinda necessary for the RS group going turbo since it leans us right out (how I blew my engine up the second time). I will make sure I take a ton of photos and photoshop where I make cuts so there is no mistake. I'm hopefully doing this the week of the 14th since I will be on break and can take my time getting it done. Probably wont get on the car in that time, but can at least mount it up to one of my spare intake manifolds to show it off.

[method]

The only downside I can see to this is your dropping flow through each bank assuming all else is constant.

[SubyFr3ak]

The only downside I can see to this is your dropping flow through each bank assuming all else is constant.

Shouldn't be considering its using the same FPR just using it to feed 2 sides instead of 1 and all the tubing is the same length as the original rails. Here is the link to the one on scoobymods that I'm going by...

http://www.scoobymods.com/forums/series_parallel_fuel_delivery-t175.html

and if people are worried it wont work right, I'll test it on my car and let you know how it goes since I'll be running my air/fuel gauge and running some tests on the cylinders to see if there is any change.

[method]

Just remember pressure and flow are completely separate measurements. For any given pressure against the fuel pump your gonna get a set flow out. If your splitting the flow by going in parallel your getting half the flow on each bank (for a set pressure)...just something to keep in the back of your head.

Looks liek this will be a great DIY!

[RCKSTR]

does anyone happen to have a link to the kit for the wrx guys? I havn't come across any of those yet and its what I need:)

[SubyFr3ak]

does anyone happen to have a link to the kit for the wrx guys? I havn't come across any of those yet and its what I need:)

I don't know if yours is top feed or side feed, but here is a side feed...
http://www.perrinperformance.com/products/show/293/Fuel-Rail-Side-Feed?category=7&model=2

and here is a top feed....
http://www.perrinperformance.com/products/show/292/Fuel-Rail-Top-Feed?category=7&model=29

[RCKSTR]

I don't know if yours is top feed or side feed, but here is a side feed...
http://www.perrinperformance.com/products/show/293/Fuel-Rail-Side-Feed?category=7&model=2

and here is a top feed....
http://www.perrinperformance.com/products/show/292/Fuel-Rail-Top-Feed?category=7&model=29

sorry, I thought you guys were talking about a diy kit:lol: not all new overpriced fuel rails

[SubyFr3ak]

:lol: Sorry for the confusion. I'll be working on mine over Feb. break, and its pretty much the same concept as those fuel rails, but if you need to bump up the pressure any you could always add an FMU like this vortech one....
http://www.rs25.com/forums/vbclassified/uploaded/2ffl0vl1u2.jpg

For me once its on the car I probably will replace the stock FPR with an adjustable one or put one of these^^ on so I don't starve the engine when I put the turbo on....

[CTATV]

subscribed

[Nate8409]

This will be better when done only thing is that if you are running out of fuel enough to feed cylinder 4 you are running out of pressure. At least that is what I would feel is happening.

Now you should be splitting the lean condition into two cylinders more evenly. Only real plus I see. Where is the FPR on your car? On the return after cyinder 4 right?

[SubyFr3ak]

As of right now there is only a fuel pressure regulator on the line in not the line out. This will split the feet to both rails evenly and the return line will be Y-ed back together so its one return line in the end so both sides have constant pressure. if you put in the FMU, that attaches to the fuel return and should increase the pressure over what your stock one is giving the engine more fuel to use before it returns it to the tank.

I think it'll be better explained when I get the set up together and on a manifold...

[kgj996]

I know a few people who run an areomotive 1:1 fpr and they work very well. I think Nick S. uses one on his 10sec mitsubishi.:)

[shtbxr22]

any progress in 2 months?

[SubyFr3ak]

any progress in 2 months?

I ended up selling the car to Bryan, lol. So it probably wont happen now. They have a write up on scoobiemods.com

I could try it with my new car, but I'm thinking Perrin rails might be in order :D

[etaks99rs]

The silver perrin side feeds are real cheap right now.

[BG @ BrenTuning]

I am a big fan of the perrin rails :)

[gling]

does anyone happen to have a link to the kit for the wrx guys? I havn't come across any of those yet and its what I need:)

Justin,

I did it myself with a little help from DSG on the welding. I have the DIY stuff in my garage since I was too lazy to put it in when I did my v8 swap. I'll try and get a picture for you if you want. I ended up using an adjustable Nismo FPR in place of the stock FPR too.

Cheers.

Gerald.

[98Wagoon]

I was just reading about this the other day. I thought it was north ursalia who did the write up. but since I cant find it, Im guessing it was someone else.. Im gonna go look for the writeup I was reading. it was really good.

[Seraphinwolf]

Either way I need a write up for a DIY as I can't just go and buy rails like the rest of you. :-/

[98Wagoon]

Either way I need a write up for a DIY as I can't just go and buy rails like the rest of you. :-/




http://www.northursalia.com/modifications/drivetrain/fuelrail/fuelrail.html


theeere it is. this is a really good write up. cheap, easy*, and seemily well thought out. Im thinking of doing it while my 2.0 is still out of the car..

*easy for some. :lol:

[Snowman87]

I ended up selling the car to Bryan, lol. So it probably wont happen now. They have a write up on scoobiemods.com

I could try it with my new car, but I'm thinking Perrin rails might be in order :D

Hmm, this would probably be where my misfire is coming from. Some days I can hear a cylinder sound like it's being starved for fuel. I guess this is my next mod :lol: I don't have the coin to spend on another motor if this one ****s the bed.