[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

octane baby! (longish but possibly good reading)



Do you mean the fuel booster stuff at parts stores?  9 out of 10 times that
stuff has never helped.  If anyone says it does I'd like to see it on a
dyno.  It goes along with the louder muffler syndrome.  If it makes more
noise run it harder,  "Oh hey!  my car is faster now!"  There are no
miracles in a bottle.  Well except for nitrous........

----- Original Message ----- 
From: "ATS - Patrick Bureau" <txrocco@sbcglobal.net>
To: "Erik" <pats16v@columbus.rr.com>; "Scirocco List"
<scirocco-l@scirocco.org>; "Dan Smith" <sad_rocc@yahoo.com>
Sent: Monday, September 15, 2003 8:48 AM
Subject: RE: octane baby! (longish but possibly good reading)


> one thing I dont understand then  if your theory would be correct
> why do you need octane 105 to run a faster 1/4 mile. :)
>
> I think you got it backwards...
>
> ATS - Patrick Bureau - txrocco@sbcglobal.net
> ----------------------------------------------
> MSN:ATSGTX@hotmail.com |YAHOO:ATSGTX@yahoo.com
> ICQ:32918816           |AIM:Texasscirocco
> ----------------------------------------------
>
>
> =>-----Original Message-----
> =>From: scirocco-l-bounces@scirocco.org
> =>[mailto:scirocco-l-bounces@scirocco.org]On Behalf Of Erik
> =>Sent: Monday, September 15, 2003 7:41 AM
> =>To: Scirocco List; Dan Smith
> =>Subject: Re: octane baby! (longish but possibly good reading)
> =>
> =>
> =>There is theory that I have been working with for a while (working third
> =>shift I have ALOT of time), and it goes a little like this:
> =>
> =>If the given Octane level is to resist Detonation (i.e. Hot spots in a
> =>cyliner) essentially what you are doing is slowing down your
> =>Flame front to
> =>a controlable level (Cooling Effect). That being said you are
> =>really getting
> =>a slower and possibly a less efficient combustion process with the
higher
> =>Octane Rating fuel.
> =>
> =>  So with a lower octane rating in reality the Flame Front is
> =>moving faster
> =>and burning more quickly, so at that point in essence the motor is
burning
> =>more of the given fuel ingested into the motor during it particular
> =>combustion process due to the faster flame front traveling across the
> =>combstion area.
> =>
> =>Example:  87 Octane fuel has less resistance to detonation than say 94
> =>Octane, hence there will be a hotter flame traveling arond the
> =>cylinder and
> =>conceivably (?) burning more of the air/fuel in the cylinder.
> =>
> =>One thing to remember with this is that it's not the Octane in
> =>the fuel that
> =>is making the power it is the cylinder pressure and camshaft
> =>profile. While
> =>a large cam will bleed off some presure in the cylinder it is
> =>also allowing
> =>a greater amout of Air/Fuel into the cylinder than a stock of
> =>very mild cam
> =>profile.
> =>
> =>This is why when a too low of Octane fuel is run a motor tends to
> =>run hot in
> =>most cases and will detonate under load.  Add the high Octane fuel and
> =>Viola! cooler cylinders, no detonation.  Detonation being hot spots in
the
> =>cylinder that pre-ignite the Air/Fuel mixture before the ignition does.
> =>
> =>I get asked this question at least 10 times a day, "What Octane
> =>fuel should
> =>I run?"  I answer  "I can't give you an honest answer.  There are far
too
> =>many variables to this, compression, cam profile, altitude, timing
curve,
> =>car weight, gearing, etc."  What I try to convey is "Run the lowest
Octane
> =>possible."  See definition above.  "If the higer octane slows down flame
> =>front you'll get a less efficient burn which equals less power."  I have
> =>been witness several dyno tests run where a motor has 87 run
> =>through it and
> =>then 92 and the motors make less power BFC goes up and V/E goes
> =>down.  Why?
> =>Because the motor didn't need or want the higher Octane fuel.
> =>
> =>Before somebody say "HEY ASS what about Alch. and Nitro?"  Well those
are
> =>not conventional fuels.  Nitro is just totally nuts.  If you pour some
on
> =>the ground and throw a match on it, it won't burn.  Hit that same
> =>spot with
> =>a hammer and BAM!  no more fingers, toes or hammer.  Alch.  has a lower
> =>Specif. Gravity that Gasoline so you have to run a greater volume in
order
> =>to make power.  Also note Alch. gets used in VERY high Compression
> =>applications, say 13-1 and higher.  And if you notice it has a supreme
> =>cooling effect.  This is part of the reason Top Fuel and Funny Cars
don't
> =>need cooling systems, and can run for as long and as hard as they
> =>do.   Now
> =>adays these two classes are running usually 75-80% Nitro and the diff in
> =>Alch. This way they can keep the Nitro under control and still keep the
> =>motor cool.
> =>
> =>
> =>What was the original question again?  Oh yeah.  Higher Octane
> =>fuel does not
> =>equal better mileage.  Tell you Housemates to do less burn outs,
> =>change the
> =>oil, and replace the air filter, and run the lowest octane
> =>possible that the
> =>motor will live on.  An efficient package is the key.  If you've ever
> =>noticed according to Bently most VW's total ignition timing is
> =>21-23 degrees
> =>before TDC.  Even the best Small Block Chevy is typically more than 30
> =>degrees.  VW has very efficient cylinder heads.  They don't need alot of
> =>ignition lead to make power.  A 93-97 275 H.P. LT1 makes .785 Hp per
C.I.
> =>and basic 1.8L 100 H.P. VW makes .925 H.P. per C.I.  sounds pretty
> =>convincing to me
> =>
> =>This was just my .02, but what do I know?  Nothing about Weber
> =>carbs that's
> =>for sure!  :)
> =>
> =>Cheers,
> =>
> =>Erik
> =>
> =>----- Original Message -----
> =>From: "Dan Smith" <sad_rocc@yahoo.com>
> =>To: <scirocco-l@scirocco.org>
> =>Sent: Sunday, September 14, 2003 6:27 PM
> =>Subject: octane baby!
> =>
> =>
> =>> Yeah, a corny play on a song title, but I couldn't resist.
> =>Anyways, CO has
> =>octane ratings at the pump ranging from 85 to 94. With gas prices
ranging
> =>from $1.77 to 1.99 respectively, I want to see if I can settle this hot
> =>debate among my housemates. Does higher octane gas equal better
> =>gas mileage?
> =>And enough of a better mileage to make it cost effective? This
> =>would be for
> =>my relatively stock 84 8v, which doesn't deserve high octane gas if it
> =>doesn't make a difference mileage-wise. When responding, please
> =>try to keep
> =>the formula equations to a minimum as high school chem was a long time
ago
> =>and I just squeeked by.
> =>>
> =>> TIA,
> =>> Dan
> =>>
> =>>
> =>> ---------------------------------
> =>> Do you Yahoo!?
> =>> Yahoo! SiteBuilder - Free, easy-to-use web site design software
> =>> _______________________________________________
> =>> Scirocco-l mailing list
> =>> Scirocco-l@scirocco.org
> =>> http://neubayern.net/mailman/listinfo/scirocco-l
> =>
> =>
> =>_______________________________________________
> =>Scirocco-l mailing list
> =>Scirocco-l@scirocco.org
> =>http://neubayern.net/mailman/listinfo/scirocco-l
>