Hold on there John...there is NO WAY that a colder plug can retard the
timing. Don't worry about that at all with the new MP Computer. Secondly,
one heat range colder will NOT shorten the life of your engine is you do
regular maintenance on the engine itself (mainly oil changes and tuneups).
Why is higher octane fuel required? The easiest (and least technical)
answer is this:
Advanced Timing ignites the fuel at an earlier state...this depends on how
much earlier: (+1 to +5 degrees BTDC). Given that the air/fuel mixture is
ignited earlier, you need a slower burn fuel to prevent the mixture from
burning too quickly (this causes "Pinging"). This is where the higher
octane fuel is required. Now, running a more aggressive/advanced timing
curve will also create more internal heat (combustion chamber) so this is
why either higher octane fuel (preferred method), a colder spark plug (no
more than 1 heat range colder), or cooler Thermostat will help your engine
from "pinging". It will NOT hurt it. The preferred method is still Higher
octane fuel but this is entirely up to your pocketbook...but take it up at
least one range on the fuel. If you already have the one range colder plugs
(3923's) RUN WITH THEM.
It IS, however, recommended by Mopar to run 92...you may want to do this
since the more aggressive timing curves in the MP Computer will (more than
likely) cause "pinging" with 87 octane fuel.
- Bernd
-----Original Message-----
From: owner-dakota-truck@buffnet.net
Subject: DML: Re: MP Computer installed
Now I'm really confused. With a stock computer, everyone, and I mean
EVERYONE is saying that you need to install colder plugs. This bit of advise
is being told to everyone whether they have ping problems or not. Check the
archives and one thing will stand out "Get 5223 or 3923 Autolites and your
truck will run better". There is even someone who says they have a dyno
chart that shows the colder plugs develop more horsepower. Now I understand
that colder plugs retard the timing a bit, but if this is bad, then why is
everyone being told to install them?
Yes, I know the MP comp advances the timing and this is one of the ways it
makes more power so I would be defeating the computer to an extent, but I
still eliminate the ping right? And at fraction of the cost of constantly
filling up with more expensive gas. On the stock computer, 89 and higher
octane made my trucks performance drop. The power wasn't there and my
mileage went down.
But, now that I have the MP comp all I'm hearing is that cold plugs are bad
and will lead my engine to an early death because the plugs won't cure the
ping, whether I can actually hear it or not. Everyone is saying to ditch the
plugs and put higher octane gas in the tank.
Folks, I'm getting as tired of this thread as you are and aside from sending
a "Thank you" message to all who made worthwhile contributions when it's
over I still haven't seen a single post that says why higher octane is
needed and colder plugs are bad. The only thing I have heard is "Welcome to
the fried piston club", "Mopar says you need to run 92 octane", "We know
what we're talking about". I don't doubt any of these things except for one
thing. No one has yet said WHY this is.
John
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:53:45 EDT