Reducing turbo lag (lagless)?

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  • Animal Mother
    S2Forum Extremist
    • Jul 2007
    • 1135
    • Country: England

    #1

    Reducing turbo lag (lagless)?

    The turbo wastegate was explained to me today (correctly I hope) and to me it seems that it is responsible for turbo lag.
    Is there such a thing as a (relatively) lagless turbo (not a supercharger)?
    Anyone tried the mod if it exists?
    What would holding the wastegate open do?
    Sorry if this seems a little but I am new to the forced induction world .
    UrS6 - Homefry, Bailey DV, PiperX filter, Samco hoses, H&R springs, 3" D/P back zorst, 270bhp and 260ftlb :rock:

    Triumph Daytona 955i - mmmmmm :fire:

    80 dag dag :driving:
  • terrybullwon
    S2Forum Zealot
    • Mar 2006
    • 8782
    • Country: England

    #2
    Originally posted by Animal Mother
    The turbo wastegate was explained to me today (correctly I hope) and to me it seems that it is responsible for turbo lag.
    Is there such a thing as a (relatively) lagless turbo (not a supercharger)?
    Anyone tried the mod if it exists?
    What would holding the wastegate open do?
    Sorry if this seems a little but I am new to the forced induction world .
    To reduce lag the AR ratio of your turbo, the smaller the quicker the turbo will spool and viser verser...
    Also a long inlet track will cause lag as you have more air space to fill, this is where the reverse manifolds come into it. Also a stiffer waste gate spring and correct mapping of the wgfv

    But if the AR is to small it will create back pressure and choke the engine.

    Cheers James
    Last edited by terrybullwon; 19 September 2007, 00:44.
    Chef

    Comment

    • gnutz2
      S2Forum Maniac
      • Aug 2006
      • 928
      • Country: England

      #3
      Holding the wastegate open will increase the turbo lag, holding it shut is common practice to reduce lag.
      But careful design of the engine can make a more driveable car like correct size turbine a/r and header tube dia, longer and narrower inlet tract including the IM and carefully choosing your C/R and some squish. Shorter gear ratios do well with gaps between gears not too big and it doesent help if your in a big heavy S2 aswell.

      But here`s the lag free turbo you wanted http://www.hiperturbo.com/

      Variable A/R.
      The ONLY S2 Golf!
      http://www.s2forum.com/forum/showthread.php?t=19402
      10.42@138mph
      https://m.youtube.com/watch?v=0wnkkOfFpXg

      Comment

      • Animal Mother
        S2Forum Extremist
        • Jul 2007
        • 1135
        • Country: England

        #4
        Originally posted by terrybullwon
        viser verser
        Sorry, couldn't let this go. It is one of my pet hates.

        It is VICE VERSA!!
        UrS6 - Homefry, Bailey DV, PiperX filter, Samco hoses, H&R springs, 3" D/P back zorst, 270bhp and 260ftlb :rock:

        Triumph Daytona 955i - mmmmmm :fire:

        80 dag dag :driving:

        Comment

        • Jas11n
          S2Forum Zealot
          • Jan 2004
          • 5067
          • Country: England

          #5
          Originally posted by Animal Mother
          "The Quattro is evil, an insidious witch in the guise of state-of-the-art engineering, a circe who commands your obedience every waking moment and a succubus who haunts every dream. She's the seductress who recreates That First Time all over again, who snips all your tethers to innocence and changes your life forever." - Four Wheeler Magazine
          And this is one of mine..............It's "quattro" not Quattro
          Although granted, you didn't write, but you still quote it :mischeif:
          2001 Avus Silver B5 RS4.
          2004 A4 Avant 1.8T quattro Sport-LE.
          1995 S2 Coupe - sold (sniff)

          Comment

          • Animal Mother
            S2Forum Extremist
            • Jul 2007
            • 1135
            • Country: England

            #6
            Originally posted by Jas11n
            And this is one of mine..............It's "quattro" not Quattro
            Although granted, you didn't write, but you still quote it :mischeif:
            I am afraid you are incorrect
            Officially, the model name was simply "Quattro", although the graphics on the car, confusingly, refer to the four-wheel drive system and use a lowercase "q". The word "quattro" with the lowercase "q" is used to refer to either the Audi AWD system, or any AWD version of an Audi automobile.
            UrS6 - Homefry, Bailey DV, PiperX filter, Samco hoses, H&R springs, 3" D/P back zorst, 270bhp and 260ftlb :rock:

            Triumph Daytona 955i - mmmmmm :fire:

            80 dag dag :driving:

            Comment

            • Jas11n
              S2Forum Zealot
              • Jan 2004
              • 5067
              • Country: England

              #7
              First I've heard. Prove it :mischeif:
              2001 Avus Silver B5 RS4.
              2004 A4 Avant 1.8T quattro Sport-LE.
              1995 S2 Coupe - sold (sniff)

              Comment

              • Jas11n
                S2Forum Zealot
                • Jan 2004
                • 5067
                • Country: England

                #8
                I thought lag was just the turbo waiting for the exhaust pressure to become great enough to start spinning it to the point where it boosts. Also it has to overcome it's rotational inertia.
                I kinda like that bit of lag.
                Last edited by Jas11n; 19 September 2007, 03:33. Reason: spelling, Doh
                2001 Avus Silver B5 RS4.
                2004 A4 Avant 1.8T quattro Sport-LE.
                1995 S2 Coupe - sold (sniff)

                Comment

                • Jamo
                  Retired OG Mod
                  • Mar 2004
                  • 21750
                  • Country: United Kingdom

                  #9
                  Originally posted by Jas11n
                  I thought lag was just the turbo waiting for the exhaust pressure to become great enough to start spinning it to the point where it boosts. Also it has to overcome it's rotational inertia.
                  I kinda like that bit of lag.
                  The following affect lag response, exhaust back pressure, inlet track length, exhaust manifold design, boost control method, engines gas flow, turbo AR

                  The wastegate in the S2 does increase lag slightly but thats because of the way the ecu controls boost. The WGFV periodically sends boost pressure to the WG causing it to open and close slowing boost pressure build up.

                  Depends also on what people call lag, typically it can be defined as the turbo response time in which the driver can people positive boost being produced during acceleration.

                  Comment

                  • s2driveruk
                    Super Moderator
                    • Jul 2003
                    • 12696
                    • Country: England

                    #10
                    Originally posted by Jas11n
                    ....Also it has to overcome it's rotational inertia.
                    I kinda like that bit of lag.

                    Likewise...a turbo motor should have a bit of lag, really not a fan of the newer cars with no ability to count in the pressure rise. Half the fun of driving it is deciding when you can bury the big pedal waiting for the explosive push out of a corner as it comes on boost
                    sigpic

                    1992 3b S2 Coupe

                    Comment

                    • GazzaG60
                      S2Forum Freak
                      • Mar 2007
                      • 4133
                      • Country: United Kingdom

                      #11
                      if we are taking a good working engine the best way to reduce lag is to fit a proper exhaust. fit a full 3".

                      after that you will see a difference in off boost and on.

                      if it seems more laggy in the 3rd, 4th 5th, 6th areas then id say valve lift in the wastegate. the only real way to help here is to equalise the pressure chamber in the gate by applying pressure to the top port to hold the valve shut.

                      Comment

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