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

[John Cassidy/Sallyann Mulcahy <jcasidy@uswest.net>]

Facinating!
The old platinum's in my '84 4sq ran excellent for close to 100kmi.!
John Cassidy

Lewis, Gary M wrote:

> 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