Fuel Lines

[Spilner521]

anyone know what size the stock fuel line is? and also what type of fittings will work best to connect it to braided line?

[Spy]

Originally posted by Spilner521@Jul 16 2005, 07:42 AM
anyone know what size the stock fuel line is? and also what type of fittings will work best to connect it to braided line?
Quoted post


Don't know the stock size... but here's my .05

-AN fittings w/ steel braided line... have the fuel rail tapped for whatever size -AN fitting you intend to use... I"m thinking it might end up being -3AN or -4AN... and get a universal regulator like that from AEM and have the the fuel rail adapted to accomodate that as well... a machine shop that deals with some custom automotive work should be able to help you out in that department.

[Oldsman]

what are looking to do?

like spy said just have your fuel rail drilled and tap. works great.

[Spilner521]

for my fuel setup for the turbo, i'll be using 4 additional injectors - 1 for each port on the HO intake manifold. what i'll be doing is running the stock feed line into a T fitting, and from there one side will go to the stock fuel rail, and one side to the additional rail. i'll need fittings to connect the stock rail to the T and the T to braided line going to the second rail.

will drilling and tapping the stock rail still work well for this setup? or would i be better off splitting the feed line with a T like i had originally planned?

[FormulaNERD]

whats so wrong with bigger injectors and a custom fuel rail?

[Spy]

Originally posted by FormulaNERD@Jul 17 2005, 06:35 PM
whats so wrong with bigger injectors and a custom fuel rail?
Quoted post

it's not even a matter of a "custom" rail, it's just adding some fitting and modifying the rail to accomodate a different type of fuel line...

4 additional injectors? what are you goign to have running them?

My fuel system is extremely simple... and it got me running a high 13 with minimal tuning.

spy's example..
-Casper's AFPR *will be swapped to an AEM universal*
-440cc injectors RC Engineering
-GM S/C reflash
-Apexi S-AFC
-AEM wideband
-*upgrading fuel pump for 12+lbs of boost action*
-*fuel lines changed to braided w/ -AN fittings for ease of maintanence*

honestly a really simple setup that definitely works, and will continue to put out the goodtimes.

[Spilner521]

i would absolutely go with the reflash if i could, but i have a 99. also i've checked some dealers around here and not one has heard of it or will do it. so i'm running 4 additional injectors. my reasoning for this is that this car is my daily driver and i cant really afford to have a lot of downtime. so i wanted something that was streetable without having to do excessive tuning to idle and run out of boost. so when i'm idling or driving out of boost, the engine runs like stock, on the stock injectors. and when i hit boost, the extra injectors kick in and add the necessary fuel needed. the only part i have to tune is the fuel delivery in boost. i'm using the greddy rebic III AIC to control 4 320cc injectors. i also have 4 aluminum injector bosses to weld into the runners in the HO manifold. should be pretty simple and straight forward to install.

so i was thinking about how to run a feed line to the second rail and i came up with 2 options. one you mentioned, spy, and i elaborated on a little, and the other i had in mind already.

1) i would drill and tap a hole right in the middle of the stock rail between the middle injectors. then have a 90° fitting from that hole, run through a braided line to another 90° going into the middle of the second rail, also between the middle 2 injectors. seems simple and clean looking to me.

2) i would split the feed line with a T fitting right were it takes a 90° bend down and into the stock fuel rail, next to the power steering reservoir. the stock line would flow straight across the top part of the T and into braided line feeding into the side of the second rail. the bottom part of the T will feed the stock rail. also seems fairly simple and clean looking, but would involve a few more fittings.

is one way better than the other or just different ways of doing the same thing? which way would flow better and distribute the fuel most evenly? also on a side note, how much power/boost will the stock fuel pump provide enough fuel for?

[Spy]

Originally posted by Spilner521@Jul 18 2005, 06:53 AM
i would absolutely go with the reflash if i could, but i have a 99. also i've checked some dealers around here and not one has heard of it or will do it. so i'm running 4 additional injectors. my reasoning for this is that this car is my daily driver and i cant really afford to have a lot of downtime. so i wanted something that was streetable without having to do excessive tuning to idle and run out of boost. so when i'm idling or driving out of boost, the engine runs like stock, on the stock injectors. and when i hit boost, the extra injectors kick in and add the necessary fuel needed. the only part i have to tune is the fuel delivery in boost. i'm using the greddy rebic III AIC to control 4 320cc injectors. i also have 4 aluminum injector bosses to weld into the runners in the HO manifold. should be pretty simple and straight forward to install.

so i was thinking about how to run a feed line to the second rail and i came up with 2 options. one you mentioned, spy, and i elaborated on a little, and the other i had in mind already.

1) i would drill and tap a hole right in the middle of the stock rail between the middle injectors. then have a 90° fitting from that hole, run through a braided line to another 90° going into the middle of the second rail, also between the middle 2 injectors. seems simple and clean looking to me.

2) i would split the feed line with a T fitting right were it takes a 90° bend down and into the stock fuel rail, next to the power steering reservoir. the stock line would flow straight across the top part of the T and into braided line feeding into the side of the second rail. the bottom part of the T will feed the stock rail. also seems fairly simple and clean looking, but would involve a few more fittings.

is one way better than the other or just different ways of doing the same thing? which way would flow better and distribute the fuel most evenly? also on a side note, how much power/boost will the stock fuel pump provide enough fuel for?
Quoted post



the stock fuel pump on my car started crapping out on anything above 12psi....
I am using 440cc injectors, but regardless of what we did w/ the S-AFC to add fuel in the top end, it just started leaning out... fuel pump isn't flowing enough fuel by that point for my car and it's needs.

Rebic three eh?.... and no reflash abilities... I"m not going to lie, I had to go to two different dealerships and talk with the second one and make a battle plan to attack GM before we could reflash the car... once we knew how to do it, it's fairly simple process which takes less then an hour....

My only other fuel system alternative for you would be in my opinion, an Apex S-AFC, 320s or 370s injectors, an adjustable FMU, Adjustable fuel regulator, and a wideband to get it tuned proper.. with the S-AFC you can tune down the fuel flow at idle so that it idles like stock, and have the FMU do the work when you hit boost, whlie using the S-AFC and Adjustable fuel regulator to fine tune things even more. The wideband would just help you keep an eye on things to keep it all in check...

[Spilner521]

S-AFC, injectors, adjustable FMU and adjustable regulator were actually my next option if i couldnt find a decent price on the rebic III or a different AIC. i have the Rebic III and everything else i need already, just wondering which option would be better for feeding the second rail....tapping both rails in the middle and connecting it with fittings and a braided line, or splitting the feed line with a T and running each side to each rail. I'm thinking its probably just a different way to do the same thing, but i'm not sure if one will flow better than the other. if anyone has any input on that it'd be a great help.

and 12 psi for the pump eh? i'll be good on that for a little while then.

[Spy]

Originally posted by Spilner521@Jul 19 2005, 02:29 AM

and 12 psi for the pump eh? i'll be good on that for a little while then.
Quoted post


that was my take that the pump was maxxed out... I upgraded everything else in the fuel system, beyond changing all the lines to some exotic braided hotness. And when trying to tune things to 14lbs, we kept on finding a lean condition at the top end consistently happening all the way down to about 12psi... so we just recently set the car up for 10psi...so considering everything else was pretty much all set for abuse, the fuel pump was the last piece that needs to be pumped up.