Re: knock sensor

[mousetrap@juno.com]

On Thu, 29 May 1997 00:21:58 +0000 "Jay Docherty"
<jdoc@postoffice.ptd.net> writes:
>> Subject:       Re: Compression questions
>
>> Not to nit-picking but....  NO!
>> 
>I didn't think so.

>  I might sound silly but what is excatly involved 
>in upgrading to a knock sensor?  I would like to on my mk1.  I just 
>put a 1.8 in it that has a motorsports head gasket. Will I have 
>problems cause there is no knock sensor
>
>                                      Jay
>'80 Scirocco 1.8 8v

On your Mk1, did you change anything in the fuel or ignition systems, or
did you just drop in a 1.8 longblock?  I am guessing from your question
that you just did the longblock.  Is it a solid lifter 1.8 9:1CR (like
stock '83-'84 GTI) or hydraulic lifter 1.8?  Hydraulic lifter 8v 1.8's
came in two CR's.  8.5:1 in A2Golf/Jetta & 10:1 in A2GTI/GLI.

If you are running the 10:1, I suggest fitting the knock sensor ignition.
 It is easiest to obtain from an '87 GTI or GLI.  Many of the parts are
common to other years and cars, but everything you need should be
available in an '87.  Some CIS-E cars do not have separate control boxes
for the injection and ignition systems.  I believe that the '85-'87
GTI/GLI all have separate boxes.  From '88 and up, it varies.  Some parts
can be sourced from Audi 4K if you have trouble finding everything.

You need:

Knock Sensor ignition control box.
Knock sensor (~1" doughnut shaped thing between #1 & #2 cyliders on front
of block)
Distributor (does not have a vacuum actuator on it)
Throttle body switch assembly

If you don't already have an electronic ignition, add in:

Ignition amplifier (any A1/A2/Audi with electronic ign)
heatsink/bracket that the amplifier mounts to
Coil (again from nearly any VW/Audi electronic ign)

I like to use the sparkplug wires that do not have the locking ends, so I
use the early style cap (pre 85) on the late model distributor.  All the
pieces go together pretty logically if you have the wiring diagram from
the A2 Bentley manual.  If not, New Dimensions has a schematic on their
website www.newdimensions.com
If you can get the wiring harness out of your donor car, it even stays
color coded throughout.  If the harness is from '85-'86, you need to
change one wire.  Seems the control box holds two different ignition
maps, one intended for VW's transverse layout, and one for Audi's
longitudinal layout.  Audi's gives a little more power (2hp).  Starting
in '87, VW started using the Audi map.  That's why the '85-'86 GTI spec
was 100hp, but in '87- it was 102hp.

I have mixed opinions about what sparkplugs to run.  The stock Bosch
WR7DTC is a superior plug based on seat of pants driving feel, but wears
quickly and (at least with the setup I run in my Jetta) gives poor
emissions reading at idle (lots of unburnt HC).  The Bosch Platinum does
not seem to have the top end power of the triple electrode copper plug,
but gives nearly zero HC and CO at the tailpipe under idle and dyno
testing.

If you want more information about the KS conversion, drop me a line.

Mike
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