Turboin CIS 8V.... BOV or CBV???? HELP!!

[jdbubb at ix.netcom.com (Dan Bubb)]

Any fuel system that measure mass air flow (like CIS) should have a CBV or
diverter valve that reroutes compressor outlet air back around to its inlet.
Just blowing of the outlet air to atmosphere will probably result in
driveability issues.
Two thoughts:
1) the only difference between a CBV and BOV is where the outlet of the
valve is routed, so I'm not sure I see any real diffenence in cost.
2) my nephew has been running 7 psi boost for a while now without either a
CBV or BOV. As of yet he has had no turbo issues. So, depending on how much
boost you intend to run you may not need one. If you're sticking with the
stock CIS (i.e.NOT a Volvo or Audi fuel distributor) you won't be able to
run that much boost anyway.
As a side note; I do intend to install a diverter valve on my nephew's car.
It's just been a question of finding time. His time and my time.
Dan

----- Original Message -----
From: "Jesse Reid" <scirocco_clan_man@hotmail.com>
To: <scirocco-l@scirocco.org>
Sent: Sunday, September 14, 2003 9:22 PM
Subject: Turboin CIS 8V.... BOV or CBV???? HELP!!


> Hey Guys, whats up?  I'm gonna be turboing a 84 Scirocco 8V and I've been
> doing some reseach, I came across this page
> "http://wwwrsphysse.anu.edu.au/~amh110/Technical_pages/blow_off_valve.htm";
> and it says:
> "A Compressor bypass valve (CBV) must be used with Bosch K-Jet injection,
as
> being a closed system, any loss of air for which fuel has already been
> metered by the movement of the airflow sensor plate, will result in an
> over-rich condition and possible backfire"
> So does that mean I need to use a CBV rather than a Blow off valve?
> I do not have the extra money to install a new engine management system,
so
> please tell me if I have to use a CBV or if BOV is the way to go, I'd love
> to hear your opinions or what you've done.
> Thanks
> Jesse
>
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