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Re: Spark Shrouding

To: "Larry Paulick" <larry.p@erols.com>
Subject: Re: Spark Shrouding
From: "Tim Ronak" <timinvan@fox.nstn.ca>
Date: Sat, 5 Jun 1999 23:52:24 -0600
Larry and listers,
Boy do I feel like the new guy getting beat up I make one suggestion and....
Don't believe every thing you read. Most of you probably know that we are
dealing with a dynamic system and the reason for indexing plugs is that you
are trying maximize HP out of a given engine. So if you do a dyno test and
forget to check for the % of unburnt gases or fatten the jets up as the
plugs are now oriented to make use of the fuel charge. So a perfectly jetted
and tuned engine may not see and increase but did they try to fatten the
jets after indexing to take advantage of the fact that the burn is more
complete. Smokey Yunik (a chevy guy) did a ton of this sort of stuff and
decided that it was beneficial. His reasoning was that if there is less
unburnt gas exiting the chamber it is burning more complete. With our engine
we saw an improvement because the engine may have been jetted a little fat
for the configuration that the initial dyno run was on. How many of you have
heard of a stub stack??? If you have a perfectly running and jetted carb how
much extra power will it give??? zero! but guess what ...on our car we could
up the jet size  and gain power..only a few HP but it was not there
before...go figure?!? We are dealing with a dynamic process ..change one
variable and we have a new game and we need to maximize the new system
totally.
By the way a dig at Hot Rod...last month I spotted an article that was
talking about how they were comparing EFI throttle bodies and carbs and they
could not understand why a throttle body(as in an EFI mustang) when rated at
600CFM was able to flow more than a carb rated at 600CFM. Well the fuel
takes up some room in the carb and presto there is less room for air. So the
EFI has higher airflow because it is dry air.
You know I do the indexing because I feel it is beneficial. But not everyone
feels the need to extract every bit they can from their engine.
Bye for now gang,
boy I must have picked a sensitive topic
Tim Ronak
B382000680
----- Original Message -----
From: Larry Paulick <larry.p@erols.com>
To: Tim Ronak <timinvan@fox.nstn.ca>
Cc: <laifman@flash.net>; Tiger News Group Address <tigers@autox.team.net>
Sent: Friday, June 04, 1999 6:58 PM
Subject: Re: Spark Shrouding


> Five or six years ago, one of the hot rod mags had an article  on idexing
the
> plugs, and they dynoed the set, with no increase in power.
>
> As I did not see your dyno results, I would like to know if your dyno
results
> showed an increase in power.  That is the real test for any change to they
> Systems.
>
> Larry
>
> Tim Ronak wrote:
>
> > Steve,
> > Given the dynamite example you are probably right as the fuse directs
the
> > ignition but with a skinny spark you do not want to shroud it at all as
> > where the fuel charge is ignited is important to get it to all burn at
once.
> > IE: ignite in the center and the flame front races outward to the edges
of
> > the cylinder together. If we ignite off to one side due to a shrouded
spark
> > it then has to race across the entire chamber to burn all of the gases
and
> > given the speed that all of these things happen some of the gas is
expelled
> > un burnt.
> > I bet that Doan guy with his 300HP 260 indexed his plugs so the opening
> > faced down.
> > Since i have not stood inside a cylinder under combustion it is more a
> > religous conviction that indexing is a good thing, rather than a
> > quantifiable fact.
> > It works for me.
> > regards,
> > Tim Ronak
> > B382000680
> >
> > PS: I bet a Titan rocket engine would make a 2400lb Tiger scoot right
along
> > with out indexed plugs.
>
>
>
>


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