WUR/CPR was Re: [urq] Parts recommendations

[Ben Swann]

Jim,

I thought the valve opened on warmup.  Anyhow- you are probably right.  Just
trying to understand how this operates better.

I was wondering is there a sensible way to re-plum this to provide greater
enrichment under boost.

Also - there are two lines on the CPR/WUR.  Do you know how they operate?  I
was just redoing the vacuum lines on mine and was puzzled why they did it
this way and why both ports are used for the thermo-time switch control.

Ben

[Date: Tue, 29 Mar 2005 19:46:19 +0100
From: "James Howard" <spam.me1 at ntlworld.com>
Subject: Re: [urq] Parts recommendations
To: "Ingo Rautenberg" <i.rautenberg at waratap.com>, <urq at audifans.com>
Message-ID: <006301c5348f$99fd9e30$657ba8c0 at jim>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original

The thermo valve closes as the engine warms up.
When the engine is cold, the valve is open and fuel control pressure varies
with vacuum.
When the engine is hot, the valve is closed and full vacuum is held on the
control pressure reg (after the 1st decel) until a WOT event when the 2 way
valve on the bulkhead opens and positive pressure is allowed through to
dispell the vacuum.

The control pressure reg does not enrichen further on boost, only leans on
vac - it is at full enrichment travel at atmospheric pressure.

Ergo, without the thermo valve, you have no cold running or WOT enrichment
control, as the control pressure reg will be maxed out at part throttle even
with a hot engine.

Jim.]