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Re: got the 9a this AM



>You cannot use digifant injectors with ANY type of CIS system.
>
>Chris DeLong

Right-o, here's the message from the VW Auto-X list I was thinking of when
I mentioned that:


----begin included message----

There is nothing about a CIS injector that makes it an "Audi 5000 injector".
All 5000s from '78 until '87 have the same injector part number as the
same-year Volkswagen, whether it be a Rabbit, Jetta, Fox, Golf, whatever.
All CIS stuff ('75-'87), and all CIS-E ('85-'87) stuff will interchange
within this group. If you tear the shiny air-shroud caps off the later
injectors, there is absolutely no physical difference between any of them.
16V, 8V, 10V, whatever.

'87-'91 5000s/100s (2.3 10V 5 cyl, known as CIS-E III) use the exact same
injector part number as the '90-'93 Volkswagen 2.0 16V (CIS-E Motronic).
These have higher opening pressures, and finer threads where the line
attaches, compared to traditional CIS injectors.

5000 turbo injectors all have higher flow rates compared to NA injectors.
'86-'91 "MC" Turbos have CIS injectors like toilets, compared to Rabbit
injectors. These "MC" code Turbos have the same funky fine thread as the
CIS-E III injectors, so you won't see these on a Rabbit or Golf.

The bottom line? Compared to today's Motronic systems, Aftermarket EFI, or
even the injection part of Digifant , CIS is very outdated. CIS outperforms
most garden-variety carburetors. That's all. Why? Because the fuel mixture
is _never_ perfect with a carburetor. Mixture is important. But once the
mixture is close to perfect, that's it. No more gains to be made with fuel.
 From there the quest for power must go to reducing airflow restrictions.
Here is a startling revelation for apparently a lot of VW racers: CIS is the
most restrictive FI system ever devised. CIS-E is a bit better, for reasons
I won't go into here.

Unlike most carbs, CIS gets the right amount of fuel sprayed into the engine
at varying loads and speeds. So why would modifying _that_ help? It
cannot. An engine cannot make use of any more fuel than the appropriate
amount.

----end included message----

All in the best interest of accuracy.  BTW, the FPR is somewhat attached
to the fuel distributor / air box assembly actually, smallish canister
with the fuel return line attached to one end, a 'vacuum' type line at
the other, and another smaller fuel line coming off the side. I'll have
a picture of it up shortly.

==Brett


>
>
>>From: <jester@westfailure.net>
>>To: Brett Van Sprewenburg <brett@netacc.net>
>>CC: scirocco-l@scirocco.org
>>Subject: Re: got the 9a this AM
>>Date: Sun, 9 Dec 2001 04:47:54 -0600 (CST)
>>
>>On Sun, 9 Dec 2001, Brett Van Sprewenburg wrote:
>>
>> > Please see the Motronic conversion tech procedure on scirocco.org, as
>> > (most) all your questions will be answered.  The only piece that's missing
>> > (which I'll add shortly) is to use the Motronic fuel pressure regulator,
>> > but you'll have to build an adapter...details to to be posted soon.
>>
>>As for the FPR, where is it located on the passat? i might have to go back
>>and get that :(
>>
>> > Wrong.  Almost all CIS injectors are basically the same, except for
>> > the CIS-III units (Motronic and Digifart) which have different operating
>> > pressures and flow slightly more.  This topic _just_ went through the
>> > VW Auto-x forum.
>>
>>Hmm, i was just reading on another site, that mercedes 190E cis injectors
>>flow more than others... will digifart injectors work for me, i probably
>>wont run into another passat & new injectors are pricey. I'm guessing the
>>stock flow rate is in the books, so i'll be okay there on figuring out if
>>I have any other options.
>>
>>Worse comes to worse i'm sure I can find a set of motronic injectors.
>>any tips since i'm not on the VW autox forum?
>>
>>thanks for your help,
>>
>>Steve

 \/  '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home. They're small"
\/\/ '88 Scirocco 16v (Show), '92 Passat 16v (Winter+) | - brett@netacc.net

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