[TR] Inlet Manifold Question

[Ibsen Dow]

Since this seems to be a weakness in the design of the head, the tri-manifold
with Weber's, SU's or Stromberg's that are now available for the TR 6 cylinder
engine makes more sense, if you are looking for top end performance.

Speaking of the tri-manifolds available, is there much performance on the low
end of the RPM (torque), especially with triple SU's or triple Stromsburg's,
to make that investment to convert from 2 carb to 3 carb set-up?

Ibsen

  ----- Original Message -----
  From: Tony Gordon
  To: 6pack ; TR list
  Cc: Colin Grimes ; Ibsen Dow
  Sent: Friday, May 16, 2008 6:14 PM
  Subject: Inlet Manifold Question


  I have been looking at the early/late head question for some time, and now
have a late head (many thanks to Colin Grimes ... who has a really tidy late
71 TR6, and is a really good bloke with a delightful wife to boot!).

  In a recent exchange with Ibsen Dow on this question, as I was sending him
some information from Chris Witor, I noticed that he (Chris, not Ibsen) had
made reference to the fact that he has gas flowed all the big 6 heads (and I
have his table of head characteristics ... but alas, it lacks the flow rates),
but what is interesting is the fact that he has determined that cyls. 2 and 5
are underfed with the standard 2 Stromberg manifold ... have a look at the
tables in his analysis (this was on the sixappeal website ... but its gone
from there, so I've echoe'd it ...
http://www.2simpleusa.com/triumphlist/Witor.mht).

  Any idea what Chris did to rework the inlet manifold to balance the gas
flow?  Kastner is NFG since he dealt with PI or webers only, and William's
doesn't reference any fine tuning of the standard 2xCDS manifold in his Tuning
TR250 and TR6 book ...

  I could call Chris (and since I bought some of his work-of-art oversize 1.6"
SS inlet valves - undercut and looking like they will add 10BHP just sitting
on the workbench ... NFI but I'd recommend the workmanship and service) I
think he might share, but I thought I'd see what the list thought first!

  Incidentally, Witor and Pumford (the Lucas PI guru) appear to be the top
folks in terms of their art in the UK, where there are very many more Triumph
big 6's running strongly, but not in TR250 or 6 bodies!

  **************************************
  Tony Gordon
  72 TR6
  **************************************