Date:         Tue, 02 Apr 96 14:12:35 CST
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Joel Walker <JWALKER@ua1vm.ua.edu>
Subject:      Re: spark plugs and fuel economy ???

On Tue, 2 Apr 1996 14:07:35 -0600 A Brandon Smith said:
>	So I heard someone talking on the VW list about one type of
>spark plug giving "better fuel economy" (better MPG) than another type
>of spark plug.  I don't understand how this possible?  Is it?  And if
>it is, would someone please explain to me how that works?

well, i don't KNOW that it's possible or true, but here's what i have
experienced:
- since i put Bosch triple-prong plugs (into my 88 vanagon), my anal-retentive
  recordkeeping :) has shown my AVERAGE fuel economy (over 108,000 miles)
  rise from 19.4 mpg to 19.8 mpg (over 38,000 miles). and i have done NOTHING
  else that could possible have affected the mpg. i'm using the same brands
  of gasoline, oil, filters, etc. and that's over all seasons of the year.

- my brother, the ex-mechanic, swears by the Platinum plugs. says he gets
  better mileage with them. eh? but that's what he says.

so WHY? well, "they" tell me that the Platinum plugs don't "round off" as
quickly as the old metal/material plugs. that is, the square little tip stays
square longer. ok, well, i do remember something in physics or electricity
101 (or some other class that i slept through) about sharp edges generating
electric arcing. so that sounds like it might be true. and if they stay
sharp/square longer, then the arc/spark is like new for a longer time.

and the triple-prong plugs supposedly have 1/3 the opportunity to round off
(cause there is three times the prongs to arc/spark from). so they stay
square/sharp longer.

now ... i don't KNOW that this has anything to do with anything. but i DO
know that old worn plugs or fouled plugs WILL cause your car to run badly
AND will DEcrease your fuel economy. and the more they get worn/fouled, the
worse your fuel economy will become.

and the thing is that it is harder to "prove" that something made a positive
change than it is to prove that something makes a negative change. or so it
seems to me, anyway. especially if any change that is produced is very small
and noticeable only over a long time. i mean, gee whiz, i get a WHOLE 0.4 mpg
better mileage!!! :)  and those plugs cost twice as much (but it looks like
i can leave them in three times longer). well, big deal. maybe it's just the
better quality of modern plugs altogether. i mean, things HAVE changed a
little bit in 26 years of buses. ;)

so i think it might be more the case of the snake oil: that regular changes
make a lot bigger difference than any one brand. like changing the engine
oil (and filter if you have one) every 2500-3000 miles and using a good
quality name brand ... versus Slick 50.

them's my experiences and opinions, which have no guaranteed relationship to
anything in real life. :)

joel