4 Port Fuel Rail Experience on Xcessive LIM
05-01-08, 12:39 AM
#26
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I e-mailed FJO and they confirmed it will work as I thought:
If I understand correctly, one EMS channel will drive 2 injector driver
channels? The paired channels will be a 1000 and a 1680? If this is correct,
what will happen is that each injector will open and close at the same time
[ignoring very slight differences in opening/closing response of the 2
injectors]. The difference will be that the 1000 will flow less than the
1680. What you have effectively created is a 2680cc super injector for each
rotor and the duty cycle of the injector will be what ever the EMS's duty
cycle is. Idle adjustment may be a bit of a problem with that fuel flow.
If I understand correctly, one EMS channel will drive 2 injector driver
channels? The paired channels will be a 1000 and a 1680? If this is correct,
what will happen is that each injector will open and close at the same time
[ignoring very slight differences in opening/closing response of the 2
injectors]. The difference will be that the 1000 will flow less than the
1680. What you have effectively created is a 2680cc super injector for each
rotor and the duty cycle of the injector will be what ever the EMS's duty
cycle is. Idle adjustment may be a bit of a problem with that fuel flow.
05-01-08, 12:45 AM
#27
I'm not aguing this wouldn't work, but I wonder if it's a good idea to send 1550ccs of fuel into the primary intake runners/ports and 1680ccs of fuel into the secondaries. I don't have enough data to back it up, but from a glance it seems that the secondary intake runners and ports should be seeing more airflow than the primaries. If this is the case, it would make more sense to send more fuel into the secondaries.
Here's what we know:
Stock injector sizes are 550/850. That's a 39/61 ratio, and if Mazda sized their fuel system properly we can assume the primary/secondary airflow through the stock runners and ports was something around 40/60 also.
Your proposed sizes are 1550/1680. That's about a 48/52 ratio, which might work well if your primary runners and ports are about the same size as your secondary runners and ports. It not, you might try something smaller than 1000ccs for the additional primary injectors.
1100/1680 will keep your fuel ratio around 40/60, you could accomplish that with two sets of 550cc injectors in the primary runners.
-s-
edit: not sure I understand how your fuel injectors will be installed. If you're planning to install both the 1000cc's and the 1680cc's in the secondary intake runners (two injectors per runner?) then you'd have 550/2680, which is a 17/83 ratio. Seems like you would have a whole lot more fuel going into the secondary runner, unless the PFC lets you run a different duty cycle for the primaries and secondaries (not sure as I have a different EMS).
Here's what we know:
Stock injector sizes are 550/850. That's a 39/61 ratio, and if Mazda sized their fuel system properly we can assume the primary/secondary airflow through the stock runners and ports was something around 40/60 also.
Your proposed sizes are 1550/1680. That's about a 48/52 ratio, which might work well if your primary runners and ports are about the same size as your secondary runners and ports. It not, you might try something smaller than 1000ccs for the additional primary injectors.
1100/1680 will keep your fuel ratio around 40/60, you could accomplish that with two sets of 550cc injectors in the primary runners.
-s-
edit: not sure I understand how your fuel injectors will be installed. If you're planning to install both the 1000cc's and the 1680cc's in the secondary intake runners (two injectors per runner?) then you'd have 550/2680, which is a 17/83 ratio. Seems like you would have a whole lot more fuel going into the secondary runner, unless the PFC lets you run a different duty cycle for the primaries and secondaries (not sure as I have a different EMS).
Last edited by scotty305; 05-01-08 at 12:58 AM.
06-03-09, 11:19 PM
#30
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So is there a difinitive ultimate injector setup, with regards to having enough fuel available while being able to have a reasonable idle. Is 4 injectors in Cjs secondary rail ample for 650 whp while still maintaining a reasonable idle , using the power FC. If not , please explain.
03-21-12, 06:20 AM
#36
That's a lot of fuel! What base pressure are you running? I've got limited E85 pumps in my area, so my setup will have to be flex fueled and I'd worry about drowning the engine with regular old premium at that point. Also which ECU are you using for this setup?
03-21-12, 11:03 AM
#37
It is a lot of fuel, but I was tired of changing injectors when I changed turbos and upped the boost. I'm running 50 psi base pressure, I wouldn't worry about drowning it the new injectors have much more precise control then old style ones. Running an AEM.
03-26-12, 10:40 PM
#38
I've been running ID1000's in the Xcessive LIM for a couple of years now. The OEM primaries are blocked off using Racing Beat 13B plugs, which fit well once they were trimmed an inch or two. The idle and throttle response aren't noticeably different than when the stock injectors were installed. This is on a stock 13B-REW, by the way.
Last edited by scotty305; 03-26-12 at 10:43 PM.
03-26-12, 10:47 PM
#39
I've been running ID1000's in the Xcessive LIM for a couple of years now. The OEM primaries are blocked off using Racing Beat 13B plugs, which fit well once they were trimmed an inch or two. The idle and throttle response aren't noticeably different than when the stock injectors were installed. This is on a stock 13B-REW, by the way.
03-28-12, 12:07 AM
#40
Some Honda engines have a very simple fuel rail, the fuel pressure regulator bolts to a flange at the end of the fuel rail. I picked up an aftermarket Honda FPR, fabricated a simple flange and had it welded to the end of the Xcessive fuel rail... luckily the flange can be flat, since the o-ring groove is built into the pressure regulator. There are only two fuel lines in the engine bay: the feed goes into the front of the fuel rail, and the return comes straight out of the regulator on the other side of the rail.
