boost controller project/Introduction

[Charles A. Fair]

Hello to all DIYers out there.  This might be a good time for me to introduce
myself also.

I am also new to this list.  My interest is in modifying and developing items
for my 90 Eagle Talon TSi AWD, which has the 2.0 4g63 turbo engine and my 88
Conquest TSi, G54B turbo 2.6.   I also am not an EFI guru or mechanical guru,
just love working with my cars and learning more about them.

I came to this list because I am working on an idea for a variable relief valve
boost controller.  I own a Hallman controller, which I bought back in 96.  Yes
it is expensive, slap me dammit, I didn't know any better!  Anyway, this style
of boost controller seems to be able to mechanically overcome some of the
problems of the common bleeder valve style boost controllers.  Boost pressure is
blocked from the wastegate controller's diaphragm until pressure overcomes a
spring loaded ball bearing.  The result is very fast spool time and a rock solid
pressure level at WOT.

David Buschur's RWD Talon did something like a 9.4 second 1/4th mile pass using
a Hallman valve, which he sells.  My problem with this valve is actually not
really a problem with its performance, but with adjusting it.  To make fast
spool time the vacume lines must be short.  This means engine bay mounting.  If
you run the lines to the cockpit to be able to adjust it while driving you cause
boost spike and lag, defeating the advantages of a variable relief valve over a
simple needle bleeder.

My solution is to use a motor to control the Bolt which is placing pressure on
the ball bearing.  This is very simple in operation.  In my Eagle Talon, you
actually could take a motor out of the remote controlled mirrors and mount it
with some sort of simple bracket to the valve.  It takes app. 45 degrees to
adjust the valve 1 psi.  It is not linear though.  This remote controlled mirror
motor could be adjusted with the control for the mirror, without any further
modification, very simple.  This wouldn't cost you a dime if you already had the
valve.

Oh, the Hallman is different from the variable relief valve sold McMaster-Carr
or Grangers.  If you buy the Grangers/Mcmaster valve the only similarity is its
a variable relief valve.  The Hallman uses a different way to adjust pressure on
the spring and uses a bleed hole to limit boost spike, but the principles are
the same, nothing magic.  The part numbers are on Dempsey's page also:

http://www.xmission.com/~dempsey/perform/grainger.htm

There are also some other boost controller projects there.

This guy has a pretty good variable relief valve boost controller setup if you
would like to buy one, very good workmanship.  It uses solenoid to give some
interesting settings for his 2 to 3 valve controller as an option.

http://users.erinet.com/40666/DSM-MBC.htm

I am working on a stand-alone controller for the valve.  This should be
interesting to see what comes of this.  There is not a commercially available
boost controller that uses a relief valve.  Ill offer my controller for the
valve to anybody who wants to buy it if it actually works... I can't wait to
finally get my parts.

Chuck Fair


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