[Vwdiesel] EGT Gauge Probe Mounting

LBaird119 at aol.com LBaird119 at aol.com
Fri May 31 03:44:38 EDT 2002

In a message dated 5/30/2002 9:59:47 PM Pacific Daylight Time,
jjhoehl at hotmail.com writes:

> I don't know much about exhausts - when it comes to turbos though, I thought
>  it's best to have as little restriction as possible after the turbo.
>  >I'm now considering the "ideal" to be more like 2 1/4 for an inch or so
>  >and then going to 2 1/2.
  Indeed you are correct.  My first downpipe, using 2 1/2" pipe with a
2 1/2 inch radius, on THICK "weld ell" pipe, didn't leave enough room
to tighten all four nuts from the flange plate to the turbo.  That's why I
figure a 2 1/4 for just a tad would be better overall.  I actually have 3" or
so for about a foot, after the elbow.  :)  Expansion chamber ya know!
  I ground out quite a bit around the nuts and even had to build up a
little inside where I went through, just to get 3 of the nuts on. Couldn't
get to one of the lower ones at all.
>  Is that introducing a restriction?  Or is the motivation strength and ease
>  of manufacture?  I too must make a new downpipe, and I want mine to be
>  'ideal' too. ;)
  I made the flange out of some scrap 3/8 I got for a bargain.  It was even
the correct width, just barely.  Considering the original pipe being
around 1 1/2 inch ID, in the middle, 2 1/4 isn't much of a restriction.  With
it just coming out of the turbo, it shouldn't be noticeable or not enough
when balanced against not tightening the bolts.  2 1/2 exhaust pipe might
still work.  Those weld ells are near 1/4 or so thick!  I wanted HD but I
think that might be overkill.  I also couldn't see much of a way to get
that tight of a radius on exhaust pipe without choking it down pretty
bad anyway.  Compared to that option, a short, smaller pipe and a nice
clear, pre-formed 90 should flow better.
  Clear as mud?  ;-)

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