I would have to respectfuly disagree that these early LH units are designed to compensate for all but the most basic changes - changes which are outside the closed loop lambda running conditions and which constitute 'performance' factors (acceleration and maximum power). The following variables cannot be measured by and thus compensated for by the ECU in these open loop conditions( irrespective of removing the cat)- If the engine is slightly worn (lower compression), carboned up (higher compression) , if the ignition timing, fuel atomisation or pressure are outside (and everything can add up the wrong way if you are unlucky) the parameters by which the curves are programed then you will not get optimum fueling and acceleration and maximum output will suffer. A rolling road is the only way to get the best power out of an engine for this reason. The introduction of the Lambda feedback system was for this very reason - air mass, pre programed engine parameters and a few basic engine sensors were not enough to keep the fueling within the tolerances needed to keep the cat alive and well . The amount of fuel delivered to the engine has to be calculated with the efficiency of the exhaust system as a significant factor - removing a CAT is a significant change to the gasflow characteristics and efficiency of an engine and not simply an 'upgrade' in the mild sense of the word - I repeat - to get the best acceleration and power gains you have to adjust fueling . I would'nt like to get caught without one if I lived in the US though - here in the UK it's not illegal to remove it if the car was registered after 92 and I keep my concience clear with the knowledge that my car uses a bit less fuel without it. No rant or flame intended- just at a loose end a few days into the Christmas holiday!!

posted by 195.102.197.2...

• Gutting a SPG cat, BuHuSPG, Wed, 26 Dec 2001 23:37:14
  • So whats the verdict, BuHuSPG, Thu, 27 Dec 2001 23:35:00
    • Cat Guts, SteveW, Fri, 28 Dec 2001 10:43:49
    • the turbo is the backpressure!, dave n, Fri, 28 Dec 2001 08:59:52
    • Re: So whats the verdict, Jay Hassinger, Fri, 28 Dec 2001 07:45:10
  • Re: Gutting a SPG cat, SDP, Thu, 27 Dec 2001 12:36:29
    • Sorry but I have to disagree, Jay Hassinger, Fri, 28 Dec 2001 07:55:13
    • Great thread, now what kind of cat is the best...., lms, Thu, 27 Dec 2001 17:48:20
      • Search- high flow cat, but why 3" down? (long), SDP, Thu, 27 Dec 2001 20:11:21
  • remove it with the downpipe, dave n, Thu, 27 Dec 2001 06:43:01
    • Re: remove it with the downpipe, Johann F, Thu, 27 Dec 2001 08:01:00
      • So by your logic then, Jay Hassinger, Thu, 27 Dec 2001 08:47:30
        • Re: So by your logic then, Johann F, Thu, 27 Dec 2001 09:50:11
          • Re: So by your logic then, Jay Hassinger, Thu, 27 Dec 2001 10:50:50
            • no theory here., dave n, Thu, 27 Dec 2001 16:10:07
            • Re: So by your logic then, Johann F, Thu, 27 Dec 2001 12:50:33 <-- Viewing This Message
              • Well some final thoughts, Jay Hassinger, Fri, 28 Dec 2001 07:58:52
                • Re: Well some final thoughts, Johann F, Fri, 28 Dec 2001 08:27:46
                  • Re: Well some final thoughts, Justin VanAbrahams , Fri, 28 Dec 2001 11:57:46
              • Agree- and some, SDP, Thu, 27 Dec 2001 20:28:51
              • Dunno which FI system you're referring to... but,, bazil burns, Thu, 27 Dec 2001 15:26:46
                • Re: Dunno which FI system you're referring to... but,, Justin VanAbrahams , Fri, 28 Dec 2001 11:35:45
  • Re: Gutting a SPG cat, chrisx, Thu, 27 Dec 2001 04:09:34
  • yes but just a few considerations, Quinn S. Kurz, Thu, 27 Dec 2001 01:51:26

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