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Turbo; JH or PL?






  Larry sez...
  2) By the way; free-flow exhaust on a turbo car???  :)  The turbocharger
  itself is a significant flow restriction...if it weren't, there wouldn't be
  any work done by the unit.  A turbocharger is about as close to free torque
  as you can get, but it ain't completely free.  As some of you know, most
  turbo exhaust manifolds are designed for anything but free flow.  They don't
  have to be; the power comes from........boost (not free flowing intake and
  exhaust systems).
  --------------------
  David sez:

  True.  However, if you don't improve flow before you get there, don't you
  run the risk of increasing turbo-lag?

  Your thinking is correct in that turbo lag is primarily a function of turbo response, but it is primarily a mechanical  response, which is a function of turbo size, although location (distance from exhaust valve) enters in somewhat as well.

  What's more, the Mk4 1.8T cars have all sorts of exhaust kits, -after- the
  manifold you mention.  Each of them offer a 5-15 hp increase in power
  (including TT, and they dyno their systems, so their figures are
  trustworthy).  While you can boost to overcome the losses the turbo puts on
  the system itself, would it not be wise to improve flow up to that point?

  You can add power this way.  It's your choice; add 10hp by installing an exhaust kit, or do it by turning up the boost by .5psi. 
  That's my point.
  (by the way, don't put TOO much faith in hp figures seen in ads for aftermarket speed parts....this applies to even our favorite vendors.  "Where money is concerned, accept no statement at face value.")
  larry
  sandiego16v