Spark plugs

["Kevin & Dianne Miller" <knmlr@xxxxxxxxxxxxxxxx>]

I have used four types; NGK, Platinum, Silber,
and Splits in my E-28 535i with Jacob's Ignition.
Jacob's recommended the NGK's for their ability to
hold up better to wider gapping, and withstanding
the hotter ignition.  No difference seen or felt.  The
Platinum's are supposed to burn hotter/cleaner, and last
longer.  They were also cheap in price.  No difference
noted.  Silber's are what BMW recommends, and I still use. 
 Regapped to
.040 in., the gas mileage had increased with all these 
spark plugs, but full acceleration didn't change, which is what I was
hoping for.
There was always a dead spot around 3,300 to 3,800 rpm's.
Nothing I did helped that flat area in the rpm band at full 
throttle.  Finally with leak tight everything-new timing gear
and chain (rebuilt top end), intake phlegm, and exhaust, the
only procedure that cured the thing was a GAS ANALYZER.
I was too lean on the mixture.
I don't use the Splitfires anymore.  No change in performance or
anything.  The porcelain cracked on 2 plugs (loose to the wiggle)
on my Wife's now defunct Miata.  It burned up to the tune of
$8,000 plus in a multiple car fire at the mall.  Now Dianne's
'forced' to drive one of the 2 E-28 535's! ;)
Of course she's driving the 5 spd, and I'm stuck with the
automatic, and it's performance intake, head and soon (in the
mail!) Stebro SS exhaust!  Life's not fair!:)

My recommendation (with no affiliations to above said except my
Wife and 2 prepped E-28's ;) is Bosch.

Kevin Miller  86'&88' 535i
Sunshine Bimmer Chapter, FL

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