FINALLY.. i found a fitting to turn the STOCK Fuel rail to -6an no problem!!!
 

https://static.summitracing.com/glob...07691erl_w.jpg

Come in 12X1.25 and 12X1.5 threads...

My buddys been wanting to change over to stainless braided lines, but i have a freakin custom primary rail designed for -an lines.. stumbled on this today.. couldn't find it before!!!!!!

can't remember if the stock bolt is 12x1.25 or 12x1.5... Anybody know!!!

cool! Links man Links! :)

Sorry... It's an earls fitting from summit 18.25

Stock size is 12x1.25

I think this will get you there!!!!

http://store.summitracing.com/partde...=KeywordSearch

I'm confused, why would you need to use this? I'm using -6an size lines and fittings with the Earls adapters for the fuel rails. Bottom of this page http://www.fc3spro.com/TECH/MODS/FUEL/fsystem.htm .
-John

I'm confused as well. Both Russel and Earls make an assortment of metric adapters for -6 AN. You need M14 x 1.5 for two of the connections, M12 x 1.25 for another, and then you can tap the secondary rail for either M12 x 1.5 or (better) M12 x 1.25 (closer thread pitch, more bite in fewer threads). Then use standard fittings...

Ummmm...

I feel kinda dumb now...

.... dunno why he kept asking me about 6-an banjo fittings with the stock thread size..... Other than maybe its cheaper than buying the adapter and the hose end..

I think it might be slightly cheaper, or perhaps the same price.

Turns a sharper angle, which might be useful. Banjo bolts don't flow as well as striaght-thru designs though. Might be an issue on high flow rate setups.

wow very cool! I've never seen that on fc3spro before! I'm going to do this with my rebuild. Anyone that has done this before, how much does this cost in total and did you replace the lines all the way back to the gas tank with stainless lines?

Banjo bolts are a compromise design.
If you got no other option, go with the banjo bolt.
If you can use the straight adapter, I'd recommending doing so.


-Ted

Part number or link please? I can't find it!

I have always used the the 12mm x 1.25 -6an that comes with the aluminum crush washer on the fpr side. (if memory serves me, it's been awhile) Should be a direct fit.

Its found here for 6.95

http://www.anplumbing.com/shop/index...&dept=Aluminum

you say stock fuel rail...but which one??? s4n/a, turbo, s5???? this looks simpler than buying diff. assortment of fittings for runnin a FPR...

I think he's talking s4 secondary fpr side

This wouldn't work with the S5 as the ends of a S5 fuel rails are welded.

holy cow !!! the s4 actually has a benifit over the s5 ??? bout time !!! great find !! added this to my list of needed parts!!

+1

exactly, but I cant find the steel fitting so I can weld them in.


Edit: I think I found them

http://www.sweetperformance.com/cart...3abf7a95cd4909

male/steel correct?

http://www.cvproducts.com/cv/product...=340&genCat=95

S4 has many benefits over S5. The threaded fuel rails is only one of many. :)

Now, for S5 rails there are several choices:

1. Cut factory ends off, weld on new fittings. Can be tricky if you don't have a source of steel AN/flare fittings (hint: hydraulic store)

2. Cut off factory ends, braze on standard aluminium AN/flare fittings. Easily done with no special tools, and aluminium fittings are easy to find at any speed shop.

3. Retrofit S4 rails. There are some fitment issues as I think the primary fuel rail is taller and thus hits the manifold runners. Also the secondary fuel rail doesn't fit at all.

4. Make new fuel rails. It's not as difficult as it sounds. You can use a pice of square tubing, make injector bungs yourself (drill press and round bar) or purchase them, and then weld on the fitting of your choice (you can even get NPT bungs and then use the easy to find AN - NPT adapters).

im right there with ya aaron..of course prob. cause i own one...you and i both know how the critics are in here about the difference's......:) he talked about thread sizes...whick one is for the s4 exactly...i searched and got a bunch of runarounds about it...

Sizes are covered on the 1st page of this topic. I posted about 3 or 4 replies from the top.

just purchased 4 of them. Hope I ordered the right part

http://www.cvproducts.com/cv/product...3116&genCat=95

Hey, I'd like to hear a little more detailed info on this method! Is there a write-up somewhere?

I don't know of any writeups on this forum, but I think the SDSEFI site has one...Let me see if I can find it.....


*goes off to Google for a few minutes*

Got one: http://www.sdsefi.com/techrail.htm

I'll be attempting to convert my S5 secondary rail to steel weld bungs soon, hopefully this weekend. I'll post pictures and information afterwards.

I just ordered half of the parts yesterday, should arrive tomorrow.

which parts did you order.

My 20B rail is undergoing the conversion to -6 right now...My FPR blew out so I had to go aftermarket. I'll let you know how it works out. Banzaitoyota is doing the welding work.

Reese

Right now, I'm only converting the lines from the end of the secondary rail to the hard return line. So I can drop in a new FPR. I'll go back and get the other lines and a -6 AN fuel filter later (when I can afford it).

http://irixbox.com/images/rx7/th000_0255.JPG

So far:

• Summit 100psi fuel pressure gauge $17
• 10 ft stainless steel braided hose $35
• 1 steel weld-in -6 AN male fitting $6
• 2 90 degree -6 AN Hose to Female -6 AN fittings $32
• 2 straight -6 AN Hose to Female -6 AN fittings $12
• 1 -6 AN Male to 5/16 in. Tube fitting $10
• 1 -6 AN hex head plug (for FPR) $3

The first batch totaled to about $123 with summit's "handling" fee.

Next:

• Aeromotive A1000-6 Injected Bypass Regulator $132
• 3 Male-to-male -6 AN couplers for FPR $28

See also http://irixbox.com/?s=rx7

:icon_tup:

Here are my s4 Rails :)

http://i39.photobucket.com/albums/e1...e/100_0531.jpg

heh, I have a set of S4 rails on the shelf.. looks familiar
http://irixbox.com/images/rx7/fuelrails.jpg

ok, so this is my idiot moment of the evening. how do I attach the AN lines to the stock fuel lines? Do I run AN directly from the fuel filter to the rails, and to the hard line returnfrom the FPR?

thank you for your help,
Ryosuke

EDITED: to make more sense.

yeah, you don't need anything special to use the S4 rails w/AN fittings, the metric to AN adapters work fine (they are often called carb adapters in catalogs)

my s4 primary w/-6:
http://pengaru.com/~swivel/cars/rx-7...w_IMG_2912.JPG

thats what i was about to say

If you are going AN, then you will be loosing the stock pressure regulator as there's no way to attach a braided stainless hose to it without welding on an AN fitting or using a hose clamp (eeewww...).

As for the filter, many people will clamp the braided stainless line onto the filter output and go AN from there. I find that to be in poor taste and it leaves potential leak points. Much better to either braze/weld AN fittings onto the stock hard lines, or replace these lines with braided stainless, or flare the hardline for direct connection to an AN fitting.

clamping SS huh... wow just wow... OK so weld/Braze fittings onto the hard lines. got it
thank you,
TR

EDIT: so what kind of pressure is comming through those rails? I thought stock was about 18psi but can't remember (fairly sure i've seen the test in the FSM) is there a calculation to find out fuel pressure with injector flow rates A and B and duty cycle C ?? or is it more a guestimate, or set number?

thank you again,

Done & Delivered

Fuel pressure is between 35 and 90 PSI according to the manual. The TII will massivly raise pressure under boost.

This should help for injector calculations. Amazing that the domain is "Turbo Saturns" :rolleyes:

http://www.turbosaturns.net/articles...orsepower.html

see my above post, cheap and simple

Fuel pressure is typically 38-40 psi static. Static means when there is no boost or vacuum applied to it.
When the car is running, the fuel pressure drops roughly 1 psi for every 2 inches of engine vacuum.... so look for 28-32 psi there, depending on your vacuum.
Under boost, all FPR's reference at 1:1 (unless they are a rising rate), so for every psi of boost you make, you get an extra psi of fuel.
At 15 psi of boost, the rail pressures go up by 15 psi... putting you at 53-55 psi total.

So peak fuel pressure = Static fuel pressure + (boost pressure x reference rate [USUALLY 1:1]).

I haven't read into how exactly an FPR works.

Does the turbo and the n/a use the same type of FPR?

I would hate to find out now that the n/a applies vacuum to the FPR while a turbo applies pressure.

Both engines apply vacuum.... the turbo engine just also applies boost.
The FPR is connected to the intake manifold via a vacuum line to a nipple after the throttle body.
So when the throttle body is closed or at part throttle, the manifold is under a vacuum realtive to the atmosphere, and the FPR drops the fuel pressure.
At WOT, the vacuum disappears, and the fuel pressure goes back to static.
On a turbo, which then starts to build boost, the FPR then continues to rise to match the boost.



The reason for this is thus: optimum fuel atomization happens at ~40 psi. This is why all car manufacturers use this rail pressure.
Now, a fuel injector is simply a solenoid valve. Apply power, the valve opens. Take away power, valve closes. Output side of the valve is the intake runners, intake side of the valve is the fuel rail.

Now, when the manifold is under vacuum, when the valve opens, there is extra pressure attempting to suck out the fuel pressure from the rail. Even if the fuel rail was at zero pressure, fuel would still be sucked into the engine. This extra sucking acts similarly to increasing the fuel pressure, and the atomization suffers. So, the fuel pressure is dropped down to keep a relative pressure differential of 40 psi.
Under boost, the opposite happens. When you have 15 psi of boost, when the valve opens, you would have an extra 15 psi of rail pressure pushing the fuel back into the fuel rail. This would be similar to having 25 psi of rail pressure on an N/A engine... and atomization suffers.
At 40 psi of boost, there would be no pressure differentil, and when the injector energized, no fuel would flow into the engine.

So, we make the fuel pressure adjust relative to the manifold pressure so that we have a constant pressure differential between the intake and the fuel rail of... 40 psi.

All FPR's work like this. Apply pressure, fuel pressure rises. Apply vacuum, all fpr's drop pressure. No difference between N/A and Turbo.