diy dual feed fuel rail confusion
 

hey I was looking at brianeack's diy dual feed fuel rail write up, and I'm in need of a little clearification. with everything installed in the car, and if you're face to face with the front of your car, am I drilling and tapping the 'front' or the 'rear' of the fuel rail? the picture make it out to be the rear, but isn't it getting fed by the pressure regulator? or is it being fed at the front and then going through the pressure regulator. if that's the case and it looks like it is, I think I've had the wrong impression/ideas about the vortech afpr/stock fpr setup.:td: thanks for any and all help, if anyone has some more pictures, maybe of their diy rail installed in their car, that'd be great. :bigtu:

P.S. yes I searched, didn't seem to find what I needed.

do it just like brain has it pictured.the

Just did that mod last week. It's just like it's pictured.

Fuel enters in the front, the FPR is the fuel return.
You want to add your barb in the rear of the rail. Or get jiggy and add a barb at each injector.

has anyone done that with their stock fuel rail??!?!!?!?!

i'll take that as either no, or that's a dumb idea.

I was talking about what Ben said about putting a barb to each injector...on a stock fuel rail i was wondering if anyone has done THAT. not tap just the one end.

easy for you to say on the internet.

yes, that has been done as well.

The thread has NOT been answered. Have you seen someone tap the stock rail behind each injector and install a hose barb?

Who did it? Link? Pictures?

I will see if I can dig up the thread/pics.

Technically the thread was answered; Ben answered my question/curiosity about the fuel pressure regulator feeding the rail or the tank.

i'd really rather just be banned from this site...as much as it has helped me out, seems like some people just don't get along.

apparently people can't ask questions anymore without being attacked.

Don't be a fucking victim. I hope you aren't crying now ...

If you act like this of course people are going to give you a hard time, it's entertainment.

EDIT: DING DING DING :gay:

i remember seeing it somwhere...i think it's over the top, but let me search.

http://images.search.yahoo.com/searc...06dee&ei=UTF-8

this helped me better identify the parts of the fuel rail.

but now that i am researching it...it doesn't make much sense to do that, unless of course...

this is nutsss.. http://www.youtube.com/watch?v=o_QyUD6V5_I

Rear, closest to the firewall.

no, the rail is a retun system....so fuel enters the front, and exits back to the tank through the fpr.

correct, what was your impression of FMUs? they clamp down on the return line and increase pressure back in the rail....just like putting your thumb over a water hose when watering the plants.

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I guess I didn't have a lot of knowledge about FMUs. I was alwasy curious as to why the fuel tank was pressurized (opening the cap lets out the pressure) all makes sense now though.

I checked out a 1/8NPT tap and sharpened 11/32 HSS drill from the tool crib at work, and will hopefully be drill/tapping this weekend.

Curly,

I'm in Tigard and have to do the same project. Want to do the diy dual feed and hook up a BEGI apfr. Maybe we should get together. Blind leading the blind kind of thing.

Love it!! Sounds like me and my buddy working on our cars.

There are several reasons why the fuel tank gets pressurized. It has a small amount to do with the amount of fuel that is pulled out of the tank, some to do with fuel returning to the tank, but mostly it's just the air in the tank being heated or cooled over a period of time.

Try this. Park your car in the garage overnight. Take the gas cap off in the morning to relieve pressure, then put the cap back on and then go park it in direct sunlight. Go back to the car mid-afternoon 3pm or so when it's been baking in the sun and open the gas cap... WHOOSH! The air in the tank gets hot, expands, and pressurizes the tank.

You might as well incorporate a fuel pressure gauge into the design.

1st Pic: My first design had the gauge mounted directly on a T-fitting inside the engine bay, but I decided I wanted to be able to see it while driving, so I mounted it to the cowl.

2nd Pic: My current design eliminates the first T-fitting the gauge used to be attached to, and instead I'm using just a single 4-way fitting.

3rd Pic: Shows routing of gauge.

4th Pic: Shows view of gauge from drivers eye, easily readable.

Well, not that you'll get to read this, but actually people get along here very well, with little moderation and MOST of us can take a little ribbing now and again.

It's not my fucking fault you can't get it up and have to take it out on the interweb.

Latah.

It's your forum, you let all these people in. :sadwavey:

if I ban too many, I get shit, if I ban too few, I get shit.

what the fuck ever. I wanted to ban this fuck days ago when he PM'd me this



but I thought nooooooo people will just bitch because I ban too many people.

:rofl: the best part is he could have at least edited all his posts....He brought it upon himself, in the last week he was posting nothing but nonsense.

Since his weener thread it seemed like every other post he made was, "nobody likes me, the mods hate me, poor me, waaaaaaaaaahhhhhhh." I guess when you're 19 your status on internet forums is pretty important. Maybe he missed the afterschool special on popularity.

hey cueball, that sounds like a good idea. I've got my 1.8 injectors now, firesleeve for my coolant lines, and a walbro fuel pump that I was planning on installing all at the same time, along with doing the mod to the fuel rail. this weekend actually. I'm going quad riding saturday, and was going to do it either saturday afternoon/evening, or possibly sunday (little busy with family, but maybe sunday morning?) if not either of those days, I'm taking monday off and I could do it then.

J I M B did it with his extruded rails

those were the ones....

https://www.miataturbo.net/braineack.../fuelrails.jpg

I've seen the stock rail modded the same though....

I don't think it's worth the hassle. It's already a PITA to get the oil filter with the DF shit in the way.

Curly,

Too many honey-doo's + I work 7 days a week. Monday is a possibility for me but it's only a maybe. Don't want to hold up your project. If you put things off to monday let me know.

Anyone care to explain to me how significant pressure drop can physically occur anywhere in the system? Anyone ever actually measured fuel pressure at the #1 injector and the #4 injector or are we just ASSuming that somehow the fuel system defies the laws of physics and any lean issues on #4 are the result of this? Unless your fuel pump wasn't up to the task I'd think you'd see a global pressure drop before any distribution problems.

Jwarriner, your arguement is perfectly valid methinks. Other people who have a physics background will tell you it's POSSIBLE that the design of the single-feed rail has the potential for a pressure drop at the far end, being as how that's where the outlet is for the stock FPR. I know nothing of physics.

There are guys who swear they fried the #4 because it was lean. Other guys will swear it was because the lack of coolant flow to the back of the block, hence the need for the famous "coolant reroute". I know of nobody who has equipped a manifold with 4xEGT's and 4xWBO2 gauges to individually measure each cylinder, and then done the before and after DFFR, and then the before and after "coolant reroute" comparison.

The bottom line though, is that for the $8 worth of parts to DIY a dual feed setup to eliminate any possible risk (even if you're not a believer) there's just no reason not to. Again, I know nothing of physics, but for $8 this mod is a no-brainer. There is absolutely no argument NOT to do it. I'll play those odds anyday.

More points of failure?

Call FM and ask Jeremy why he drops MASTER FUEL down a few points lower on DF cars compared to single feed cars.

Ben

Only on the Vishnu (and I would assume J i m B's), not the DIY stock rail.

I would guess that it has less to do with it being dual feed and more to do with the size and internal flow of the rail.

Having said that, I've got a dual feed stocker waiting to do into the car. :)

well I did the mod to my car today. drilled and tap went easy, sealed it up nice and good, and used some stainless steel fuel hose for everything but 6" going from the 'T' to the 'from tank' line. everything went fine except the #1 cylinder harness got pinched and unclipped, so I had to rotate the injector and plug it in from the top.

cueball, I'm sorry you didn't have time for it this weekend, if you have any questions, or want some pictures of my newly made dffr, just ask.

Something else to think about.

If your running a half decent ECU you can add extra fuel to individual cylinders.

I did some quick tests with my EMU, adding fuel to individual cylinders, didn't make the slightest difference to my knock threshold by adding fuel to #4.