Very large low impedence injectors should provide proper operation for the short opening times needed at idle. I've talked with some people on the SDS message board, that live where there is emission testing, one guy is using 96 lb/hr injectors in a 2 liter turbo engine, with no problems passing emission tests. Sequential injection should provide better emissions at idle, but probably wouldn't do much for the average even firing engine under other conditions.

Most all aftermarket ECU's will allow closed loop operation, the ones that offer a separate program for idle would probably be best, but mine will idle well, even if I set closed loop to operate during idle. I seldom run closed loop because my program for cruise conditions is leaner than it would run closed loop and there is a noticable fuel milege difference. SDS as well as most aftermarket ECU's offer fuel cut during decel. With SDS you can program fuel cut when RPM's are over 2000 and the throttle is closed below a programmable point or you can do as Jeff says, program no fuel under high vacumn conditions.

To achieve the goals you are after, I'd reccommend 75 lb/hr minimum, if you fail emission testing with them, I'd first suspect other areas that I have concerns about. Based on the information you have stated about your engine, I suspect that it will have low and unsteady vacumn at idle and you will probably have problems at least upto 2500 RPM. Between the low VE caused by the low CR and hipo cams. This is going to make it tough for any Speed Density system to accurately control, there are ways to damp the vacumn signal, how well it will all work, I don't know. I still think you've over done it, for a street car, only time will tell.

Most all aftermarket ECU's will allow closed loop operation, the ones that offer a separate program for idle would probably be best, but mine will idle well, even if I set closed loop to operate during idle. I seldom run closed loop because my program for cruise conditions is leaner than it would run closed loop and there is a noticable fuel milege difference.

I feel that most proven aftermarket ECUs, programmed correctly will get you past emission testing, unless my above concerns prove to be a problem.


posted by 205.160.7...

• Fuel Injecter chart??, Jordan, Fri, 21 Sep 2001 00:30:43
  • Re: Fuel Injecter chart??, SteveW, Fri, 21 Sep 2001 00:53:33
    • Cool!!!, Jordan, Fri, 21 Sep 2001 01:44:22
    • Re: Fuel Injecter chart?? A question, experts?, SteveW, Fri, 21 Sep 2001 01:10:03
      • no ...., Kevin K , Fri, 21 Sep 2001 09:13:25
      • Re: Fuel Injecter chart?? A question, experts?, chrisx, Fri, 21 Sep 2001 02:54:22
        • So even if I get a ECU that can handle large injectors it...., Jordan, Fri, 21 Sep 2001 03:54:51
          • Re: So even if I get a ECU that can handle large injectors it...., Beaudreau, Fri, 21 Sep 2001 20:34:23 <-- Viewing This Message
            • Batch v. Sequential question......, SteveW, Fri, 21 Sep 2001 22:50:14
              • Some Biased Info (link)..., Beaudreau, Sun, 23 Sep 2001 18:04:51
                • Makes sense,, SteveW, Tue, 25 Sep 2001 01:36:21
              • Re: Batch v. Sequential question......, Beaudreau, Sat, 22 Sep 2001 01:37:13
          • if you are in cal, chrisx, Fri, 21 Sep 2001 11:34:02
            • I just new you 2 could get along :o) n/m, GM, Fri, 21 Sep 2001 18:28:43
          • Re: So even if I get a ECU that can handle large injectors it...., Kevin K , Fri, 21 Sep 2001 09:20:18
          • I believe it would pass...(Long), Jeff Cunningham, Fri, 21 Sep 2001 08:11:32

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