[Healeys] Girling brake boost ratio

[Earl Kagna]

Gents:

The numbers I was given for the PBR VH40 (5/8" bore) are apparently hydraulic
inlet pressure. I have no idea as to parameters.  450 in, 1470 out - for a
boost ratio of (approx.) 3:25.  Similar calculations for the other boosters.
I am becoming more curious as well, and may follow up with the supplier so as
to understand the whole thing better.  I was reading from my 'on the 'phone
notes' of a few months ago.

Earl
  ----- Original Message -----
  From: andy pole
  To: bspidell at comcast.net ; kags at shaw.ca
  Cc: healeys at autox.team.net
  Sent: Thursday, August 20, 2009 10:06 AM
  Subject: RE: [Healeys] Girling brake boost ratio


  Earl, Bob

  Has made me wonder as well.

  I had my original bj8 girling mk2a booster rebuilt by Past Parts lts here in
the uk.

  The test figures they supplied for the rebuilt unit are:

  primary
  bar = 20
  vacuum = 24
  boost = 3:1

  secondary
  bar = -
  inhg = -
  bar = 58

  These figures show the boost is stated as 3:1 and the difference in pressure
readings on primary and secondary (bar) are more like a ratio of 2.9:1

  I believe the later girling mk2b had varying ratios from 2.75:1 and 2:1 with
the powerstop at 1.5:1

  Have not tested mine on the road as still dont have the prop shaft fitted.

  hope this helps

  cheers Andy


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