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).



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

 

 

Here are my s4 Rails

 

heh, I have a set of S4 rails on the shelf.. looks familiar

 

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:

 

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"

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.