RE: Bosch +4's in MC motor(long)

["Lewis, Gary M" <Gary.Lewis@West.Boeing.com>]

Jay said;

> Whats bad about regular platinums again?  
> 
Read this: 
copied from   
http://www.intendedacceleration.com/html/tip_16.html

Tech Tip No. 16
Ned Ritchie
Originally published in the quattro quarterly
Copyright 1997
Wrong Spark Plugs

Over the years I have traveled to many Quattro Club track event and safety
seminars.  Usually at each event the following scenario takes place.  Says
the owner of the Quattro, "I just can't believe it.  I had a tune up a few
days ago to prepare for the event and now the engine runs terrible.  I find
it hard to start and it misses under load."

I and a few knowledgeable owners will reply,  . . . bet you're using Bosch
platinum plugs.   We open the hood and sure enough there are five clean
Bosch WR7DP plugs.  Usually someone has a set of old plugs that they're
carrying around in some tool box.  The used but correct plugs are installed
and the engine runs perfectly.  

The Bosch WR7DP platinum spark plugs just do not work in the turbo
application.  I've talked to some Bosch employees, but they've not heard of
the problem, but were willing to listen.

What spark plugs should you use?  The smart thing is to use what is
recommended in your owner's manual.  Audi has done a lot of testing to
determine the correct plug, and the Bosch platinum is not one of them.

What do I recommend?  On Audi 10-valve turbocharged engines I recommend the
following:

                    Bosch W7DTC

                    NGK  BP6ET

These are a long life plug with three ground electrodes that enable the plug
to last up to three times as long as standard plugs.  But, here is a bit of
trivia about multiple electrode plugs.  Multiple electrode and platinum
plugs of any type to not work with the Jacobs Ignition System.

If your budget can afford it use the better spark plug that is used on the
Audi 20-valve turbocharged engines that was not available when the 10-valve
engines were made:

                    Bosch F5DPOR

These plugs have a pair of platinum electrodes that are side gapped, but
have a price hovering around $20.00 each!

On my 400+ hp 20-valve turbo engine it was beyond the recommended time to
replace these plugs even though the car was running well.  Upon examination
the plugs looked as good as the $20.00 plugs I was installing.  I put the
old plugs into my daughter, Marni's, 4000S quattro as an experiment, and
they've been running well for three years.
                                   INTENDED ACCELERATION
                                    (c) Copyright 1997 & 1998 Ned Ritchie