By-pass valve install - web URL

[Peter Berrevoets]

The by-pass valve is used to reduce turbo lag when shifting. It has the
added benefit of protecting the intercooler from 'blow-out', but it's
primary function is to maintain the rpm/spin of the turbo while shifting.

The problem with the existing turbos on the 5000 and 10v 200s is that on
shifting, the throttle closes and the turbo tries to compress air into the
intercooler and hoses between it and the throttle valve. This results in a
pressure spike that has on modified cars blown the intercooler end caps off.
The turbo also experiences a rapid deceleration (stalling) and when the
throttle is opened again, you must wait for it to spool up to provide boost
again - turbo lag.

This pressure spike is also the big killer of the michelin man hose as this
'spike' can reach upwards of 25psi. (someone step in if this figure is
inaccurate)

While it does improve performance on a stock engine by way of reduced
turbo-lag, it does not replace the power made by a chip or other mod. All
said and done, it will enhance your driving experience no matter what your
state of tune! It will also reduce wear and tear on your turbo by reducing
the extreme forces acting on it.

HTH

Peter Berrevoets
1990 200TQ
Toronto, Canada
http://frontpage.home.net/pjberr/

-----Original Message-----
From: Efraim [mailto:egav at wireless2000.com]
Sent: Thursday, February 22, 2001 11:02 PM
To: Peter Berrevoets
Subject: Re: By-pass valve install - web URL


Hi Peter,
I am following this thread and I wonder if you could clarify few things for
me. First, I thought the by-pass valve was used to protect intercooler. How
does this valve improve performance? Can it be used in place of the chip and
get the same results? I have already modded my 5KTQ, so can this valve
further improve performance or will it serve as a safety device only? If
this is a safety device, would strapping of an intercooler get me the same
result much cheaper and with less effort?
Thanks in advance.
Efraim
'88 5KCDTQ  327K km (203K mi) , 1.8 Bar
'90 90 103K km (64K mi)
Vancouver, Canada

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