Miata Mailing List: September 1999, Message #173

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Jay inquired:


>Can someone tell me about the extended reach plugs? 
>................  What about heat
>range/choices?  I appreciate your help......

This keeps coming up, so adding my 2 cents.  Over years have developed rule
of thumb to use Japanese plugs in Japanese cars.  Prefer Bosch in the
German cars and Autolite in the American cars. Think my stock Miata plugs
were ND.  They worked just fine as well as my current NGKs.  Unless I find
something better will stick with the NGK or ND.  For $1.49 each you can
tinker without any big loss.

Try the NGK extended reach.  Don't think you can go wrong, but don't try a
colder (shorter) range unless you are using forced induction.  I just like
them for a nice predictable throttle response and smooth running.  If there
is any HP increase will be small and unnoticeable

With nearly 40 years of automotive tinkering have seen a load of fads and
gimmicks come and go.  Splitfires, Fire Injectors, platinum tips, other
multiple tips, and spark boosters.  Think they are designed only to
stimulate their pockets and and gain is highly unnoticeable and may even
reduce performance. 

Has any one tried the Direct Hits thingies yet?
http://www.directhits.com/index.htm
Not interested in tinkering with them but thought someone else might!

Jim Creer