[s-cars] safe boost limits - Wastegate 101

[QSHIPQ at aol.com]

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[ Picked text/plain from multipart/alternative ]
Rod, the paragraph below was correct as written, what you wrote in repsonse
(starting with "no") didn't appear to be.  Restated, "the WGFV is what is
allowing the overboost to get where it is" (that seems correct - WGFV means:
no boost controller by definition).  Restated, "if this is a correct
assumption" (it is), "then winding down the wastegate would do little" (that
seems correct too).  So, I just don't get your "no" part, the "expressed" not
implied section.

No one is implying "winding down the WG to the bottom", since then you no
longer have the "waste or gate" part of the device.  In fact, preload *does*
have an effect (albeit "little" as ascribed above).  I saw no mention of a
boost controller or a spring cranked too tight (mine or another slister).  In
my case, that's usually a coil over problem anyway:)

A history lesson for you to ponder:  In europe (and early early vin's
stateside), the early urq's had a 6mm allen screw in the WG that was designed
to add a bit of preload when the "weather" was favorable.  Needless to say,
that didn't sit well with the EPA boys.  That said, EVERY WG cap on any
I5turbo can be converted to a adjustable preload type by popping the center
cap out of the WG, and adding the required screw and perch.

Thanks for your clarification, it's the "no" part of a correct post that
tickled my keyboard, nothing else.  Your revised "implied" post appears also
correct as stated, it just appears to be from another thread?

cranking down my .02

SJ

> From what I have read on the list the wastegate spring limits max boost to
> only 1.3 bar Abs, and the WGFV is what is allowing the overboost to get
> where it is.
> Is this a correct assumption, if so... winding down the wastegate would do
> little, would it not.
>
>
S4audinut writes:

No, The WG spring has more to do with getting these unacceptably high levels
(unless engine totally built) than any SW. I have some VERY aggressive SW and
it doesnt run this high when not in overboost.
Rod



Scott,
What I was saying was that people cranking the WG spring down to the bottom
has more to do with getting these high level boost settings in most cases
where I have seen excessive boost: or that a boost controller was used
improperly. I was trying to say that you can crank it down so that it never
wastes, BTDT.
I have SW that runs to 28lbs. then backs down (highest) and some that go's
only to 21 on overboost (lowest). Most people dont get their hands on stuff
that peaks above 25lbs and I have not seen any that stays at 25, so if you
arent using a controller, you probably have the spring cranked too tight
(kind of like you).
Didnt mean to imply anything else.
Rod