Re: Boost guages?

[JPGuru@aol.com]

Max, 

    A few years ago I added an Autometer 2" guage to my console pod on the
old Buick and it only goes up to 20psi but has a vacuum scale below 0psi.
 Any boost level above 18 psi is not recommended for any street car because
it is not safe due to boost spikes. These spikes occur when the transmission
is shifting gears and the adiabatic air dynamics change in the intake path
thereby creating a back surge against the turbine wheel (my turbo has
exploded twice, bolt came off and the turbo swallowed it, shredded baldes in
the intercooler, motor is great, and undamaged "Thank GOD!")
    I use the vacuum scale on my guage to determine if at idle the engine is
running to specs (-15hg/in) and can determine at which rpm does spool up
occur and boost begins@ 0psi. (that's significant).
  For $45 dollars I'm happy. When racing, I focus on cooling the intake and
plenum with ice(Dry ice if possible) and keep boost levels around 18-20psi.
 A blow-off valve is next on my shopping list (Mad Dog, HKS) to control
spikes above 21psi and on/off throttle response.  
All turbo and forced induction cars(supercharged) have to worry about this
regardless....
I have heard of worse mishaps with greater damage.(engine, powertrain).
   I  would recommend a turbo rework(bigger intake wheel, race porting, etc)
or better a bigger more efficent/built Garret turbo unit. (see Turbo and
Hi-tech. magazine, back 2-3 issues ago) to deliver more performance,800 to
950cfm at a lower boost level and temperature. remember(PV=nRT)
  
   I hope this info was informative. 
I think a 20psi guage is enough for the Typhoons/Syclones even at the
track.....
I'm on my 4th turbo unit (TA-49,.83A/R,975cfm@14.7) 

later 
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Jean G. Pierre Jr.   JPGuru@aol.com
1987 Buick Turbo-T  11's  "Great White" 
(stock, bigger turbo, no heads, cam, or NOS) No NEED!
Buick Grand National Racing Association, NY, NJ, CT, MD.
Long Island, NY
web: http://members.aol.com/jpguru/index.html
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