Re: Re:(long)audi 5000 Turbo warm up regulator?

["Winggee" <winggee@hotmail.com>]

Cool. Thanks alot! Now i have a much better understand of what the CPR does
now. only reason i asked, is cause i seen this on ebay with like all the
injectors and the fuel distributor. i dunno.. i bid like 40 bucks.. dunno if
i'm over paying or not. Plus since my car is turboed now, i don't like that
fact that the car will be leaning out when underboost.

Thanks alot!
Wing


----- Original Message -----
From: "Jonas Karlsson" <jonas85k@hotmail.com>
To: <winggee@hotmail.com>; <scirocco-l@scirocco.org>
Sent: Thursday, October 05, 2000 1:41 PM
Subject: Re:(long)audi 5000 Turbo warm up regulator?


> >From: "Winggee" <winggee@hotmail.com>
> >
> >how much does a audi 5k warmup regulator usually run for? used, new, etc?
>
> New, the dealership would prolly tear you a new one. Used, in the junkyard
it sells as a "doohickey" for about $5.
>
> >and what does it exactly do? does it use the cold start valve as an extra
injector? how does this compare with a stock one off one of our cars?
>
> No, it does not use the cold start valve. That was not designed for this
purpose. The "Load sensing" control pressure regulator (found also on Audi
Coupe GT's and 5000 turbo's, etc.) has a vacuum port to the intake manifold.
When there is boost (or low vacuum), the CPR causes the mixture to be
enriched.
>
> If that satisfies the "how" part for you, then yer done. Enqiring minds
read on, but be forewarned that it gets somewhat hairy here on out. I'll do
my best to keep it simple. This is all for CIS, not CIS-E BTW.
>
> The CPR (AKA, warm up regulator) regulates the (you guessed it) control
pressure. So WTF is control pressure? Well, it's sorta like this. Control
pressure is the fuel pressure that is "on top" of the plunger. System
pressure is on the bottom, and as the airflow plate pushes up the plunger,
the system pressure flows to the injectors. Now, the Control pressure is
pushing against the plunger, resisting it's upward movement. Here's the
basic idea--- decrease the control pressure, and the plunger is allowed to
travel further up and more fuel gets delivered to the injectors. This is how
it enriches the mixture.
>
> So what does the CPR do? It basically bleeds off fuel from the control
pressure side, and returns it to the tank. That's what the 2 lines are, one
if from control pressure, and the other goes to the fuel return line. Inside
the CPR is a diaphragm that does the "bleeding" and connected to the
diaphragm is a bimetallic strip. The bimatallic strip is wrapped with wire
from a heating element connected to +12V when the ignition is -On-. This is
what the electric plug is for.
>
> So, when the car is cold, the diaphragm is open, and fuel is bled off.
(yummy cold start enrichment). After 2-3minutes the bimetallic strip has
been heated enough to close the diaphragm and shut off the bleeding. Unless
you live in Alaska or something, and it's -20F outside, in which case the
motor is _very_ cold. Then (because the CPR is bolted to the block) the
enrichment will last until the motor is mostly warm. If you live in
reasonable climates the CPR can be relocated anywhere you want, and the car
will drive just fine.
>
> Lastly, the Audi one (there are different ones, you want the one with the
vacuum ports on the side, not just the top) basically just has a vacuum
chamber connected to the diaphragm, so that at positive manifold pressure,
the CPR bleeds off some fuel and enriches the mixture. A good idea on a
Turbo car, questionable if any improvements for a N/A car.
>
> Whew, that was longer than I planned. But now you know, and knowing is
half the battle!!
>
>
> Jonas
> 85 Scirocco 2.0
> 78 Scirocco 1.8
> For direct reply: jonas@metabolex.com
> http://www.geocities.com/scirocco2l8v
>
>

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