✕

Timing controls the point in time that the spark ignites gas. The explosion then takes time to propogate. The time that it takes for the explosion to finally hit the piston and move it is key. As we advance timing, the explosion hits the piston sooner and therefore gives more horsepower. The problem is this is a high temperature explosion, and the head and piston heat up. A chamber that is too hot &/or a spark that is too soon hits the piston before it hits top dead center, retarding it. This can cause knocking. Low octane gas is more prone to dieseling, also causing knocking. This can and will damage the engine. So run the car too advanced, and you get knocking but you get it just right and you get more horsepower so you get a higher RPM. Retarding the timing lowers head temperatures but also saps HP.

So, as you change your timing, you affect the amount of horsepower that the gasoline has, so the RPM can change. Also, the ECU senses gasoline that burns properly or improperly, and corrects fuel going to the injectors. This will obviously affect RPM.

• Timing changed RPM - why?, Tino, Sat, 26 Feb 2005 11:04:48
  • Re: Timing changed RPM - why?, JohnK, Sun, 27 Feb 2005 09:14:48
  • What does engine knock sound like., Tino, Sat, 26 Feb 2005 19:59:48
    • Re: What does engine knock sound like., Chaz, Sun, 27 Feb 2005 04:02:53
      • Re: What does engine knock sound like., Tino, Sun, 27 Feb 2005 07:27:27
  • Do you understand what timeing does?, Chaz, Sat, 26 Feb 2005 13:13:13 <-- Viewing This Message
    • A little bit, Tino, Sat, 26 Feb 2005 15:08:11
      • Re: A little bit, RayJ, Sat, 26 Feb 2005 20:37:44
        • Ray... Stand by what I say..., Chaz, Sun, 27 Feb 2005 03:19:48
          • Makes sense., Tino, Sun, 27 Feb 2005 07:44:42
            • Re: low octane, MS, Sun, 27 Feb 2005 11:38:05
              • What did you use to choke the line to the capsule? nm, Andy E, Sun, 27 Feb 2005 17:35:44
                • Any sort of restriction, a piece of tubing ..., MS, Mon, 28 Feb 2005 13:45:40
            • One advantage with the Canadian models..., Chaz, Sun, 27 Feb 2005 11:24:29
        • lol. n/m, eric 85 900t, Sun, 27 Feb 2005 00:03:38
  • Re: Timing changed RPM - why?, JohnK, Sat, 26 Feb 2005 11:40:47
    • Simple but often overlooked, Tino, Sat, 26 Feb 2005 14:56:51
    • Must have disturbed something - APC, Tino, Sat, 26 Feb 2005 12:48:06

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