4 Port Fuel Rail Experience on Xcessive LIM
#1
4 Port Fuel Rail Experience on Xcessive LIM
I'm debating eliminating my primary rail and running a 4 port rail on the Xcessive LIM. I know having a fuel injector as close to the combustion chamber is the best way to go but in spite of simplification I'm debating this conversion. Having three lines in the engine bay would be nice. One feed, one cross to the FPR, and one return line sounds nice! I'm guessing that the injector timing would have to be advanced SLIGHTLY as it's further away from the chamber.
I'm asking for someone with experience or someone that can obviously have some educated say in the matter. I would like to keep the "thinkers" out of this one. I'll think of more things to say later. As for now lets get the replies!
I'm asking for someone with experience or someone that can obviously have some educated say in the matter. I would like to keep the "thinkers" out of this one. I'll think of more things to say later. As for now lets get the replies!
#2
Keep it simple
I'm currenty getting it back together. I opted to place six injectors but running only 4 since I dont have a way to control the additional two. If you have an aftermarket fuel rail send it to Rich from Xcessive to bore the additional holes, place two injectors as block off insted of completely making the manifold hole useless, this will alow you for future mods if there are any plans. If you dont have an aftermarket fuel rail buy the Xcessive rail for convenience. CJ-Motorsports is revising their fuel system to work with the Xcessive LIM.
If you are running low impedance injectors its recommended to use resistor box like FJO injector drivers because separate resistors will slow down the circuit, an economical way to do this is sourcing out from Honda, Nissan or NA RX7 which uses low impedance injectors.
If you are running low impedance injectors its recommended to use resistor box like FJO injector drivers because separate resistors will slow down the circuit, an economical way to do this is sourcing out from Honda, Nissan or NA RX7 which uses low impedance injectors.
Last edited by S3DF; 04-22-08 at 11:51 PM.
#3
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I ran the 4 injectors only in the Xcessive manifold for a couple years. I had 4x1000cc which may not have been the best way to go. Probably the biggest issue with this setup was drivability/idle issues. It was difficult to get a clean low (<1200rpm) idle with the relatively big primaries so far upstream. It also was also difficult to get rid of an off idle stumble when touching the throttle.
I ended up moving the primaries back to the stock location and this seemed to help with some of the drivability issues. I think having the injectors so close to the port helps when you have a large injector and not much airspeed. It was also interesting that when I moved the injectors back the car ran alot richer and ultimately needed about 10% taken out of the map.
The plumbing for the 4 injectors on one rail was nice, though. Very simple and clean.
-Andy
I ended up moving the primaries back to the stock location and this seemed to help with some of the drivability issues. I think having the injectors so close to the port helps when you have a large injector and not much airspeed. It was also interesting that when I moved the injectors back the car ran alot richer and ultimately needed about 10% taken out of the map.
The plumbing for the 4 injectors on one rail was nice, though. Very simple and clean.
-Andy
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#10
I wouldn't send the rail to Keith. I send mine to Rich because Keith was going to charge more.
#15
#19
I'm skeptical because I have never heard anybody use the power FC to run the injectors in batch specially two injector size in the secondary. If your using the same pulsed width for both 1680 and 1000 they will run different duty cycles. Let us know how it turn out.
#20
Senior Member
iTrader: (5)
Since duty cycle is on vs off time, wouldn't 50% be 50% on both injectors? If this is not the case,then I guess I need to run 4 equal sized secondarys. I was wanting to run the 1000/1680, because I don't need 4 1680s. I was concerned that 4 1680s coming online would cause a rich spot that couldn't be tuned out, similiar to 850s in the primary.
#21
Lives on the Forum
To answer Lance, I wouldn't do away with the primary unless you had to. idle and throttle response is going to suffer. give me a call if you need to.
#23
Maybe I am missing something here... did I ever quote you a price to modify the rail? I dont recall that because the first person to ask was Ryan1. I am sure he is happy with the price.
To answer Lance, I wouldn't do away with the primary unless you had to. idle and throttle response is going to suffer. give me a call if you need to.
To answer Lance, I wouldn't do away with the primary unless you had to. idle and throttle response is going to suffer. give me a call if you need to.
#24
Senior Member
iTrader: (5)
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.
#25
[QUOTE=rxrotary2_7;8146792]Maybe I am missing something here... did I ever quote you a price to modify the rail? I dont recall that because the first person to ask was Ryan1. I am sure he is happy with the price.
You responded to my work email a while back. I ask Xecessive and You for independed quote at the same time Xecessive was $10 cheaper.
You responded to my work email a while back. I ask Xecessive and You for independed quote at the same time Xecessive was $10 cheaper.