I have been using Exxon 93 for a while now.

1) Its at least 5 cents cheaper than the cheapest premium I can find(at this one station) - $1.23 is what I paid the other day. In Frisco, where I live, the same gas is about $1.49. Outrageous.

2) Its Exxon, which works with my Mobil gas card.

3) No pinging from it yet, and I have ran many tanks through.

 

Just to clear up any misconceptions, dispite popular belief, a high octane gasoline does NOT make more power.I see a lot of cars putting in 93+ octane in their Taurus,Accords and alike saying that they can "feel" the performance differance.this makes me laugh! "Octane" as they call it, is just an additive added, in a percentage basis, to slow down the burning rate of the raw gasoline.This in turn provides a longer "burn" of the ignited fuel in the combustion chamber. The sole intent and purpose of this is to combat detonation (pinging) in higher compression engines or advanced timing .Thats it! When you advance the timing on a car or truck it is then and only then that you increase its power either in the form of torque and or horsepower thus requiring the higher octane fuels.Most cars can run on a lower octane fuel until either the timing or compression is altered.The idea is to use as low as an octane before it starts to ping other wise you are just wasting your money!! And BTW, sometimes advancing you car toomuch will require a higher octand but also may hurt the higher rpm band, depending on the profile of the cars powerband.Just some food for thought.

 

Almost all new cars today retard timing in response to pinging. If your engines not runnng the best, you can use higher octane to get a more advanced timing table and yes... get more power.

Of course, any car nut should realize that if you fix whatever was causing the pinging in the first place you'll get even more power without using 93+ octane, but to the idle masses, it's a fix.

 

Getting rid of the pinging with a higher octane does NOT increase power.It just stops the pinging.Its the advancing that increases the power. And using a higher octane doesn't increase the timing.Its really simple...all octane does is stop pinging..period!

 

Hmmmmm, higher octane DOES NOT increase power????
Then why is there 87,89,93,94,100,105,115, etc. octane gasolines? Why do aircraft run such high octane fuels? To stop pinging? I dont think so. I dont care what anyone says, my L runs stronger with the Texaco 93 and it does not ping anymore! If your engine is pinging as bad as mine was, you have to be losing power! Someone with more knowledge please chim in here. Correct me if Im wrong.

 

Thats right!! You don't have to believe it, but those ratings are to slow down the burn only.The higher the octane the slower it burns.Higher compression engines 12.5 and up require those 105's and up.Its hard to accept, but the fact is that these fuels are just gasoline with a bunch of "crud" in it like alchohol, detergents and catalysts like octane to( once again ) slow down the explosion of this combustable liquid.Like I said its a simple concept.I think that anybody with an engineering or Physics background would back this up.

 

Lightnings supposedly have the Knock sensors deactivated. BUT on a motor with knock sensor that actively turns Timing back to combat knock. If your Engine is knocking your engine has turned back the timing as far as it can.

If you add higher octane fuel the knock sensor is NO longer turning back the timing then you may see an increase in power.

As stated above the power comes from being able to run more timing NOT from the octane itself.

Doug

 

Mondo and Doug are correct. You can actually slow down(less hp) using a higher octane fuel than than with the proper octane number. Ran a full tank of 130 air craft fuel through a 1957 MGA and burned most of the valves--rescued by a 1950 Hudson driver.

Dan

 

(Octane is an additive, I don't think so.) Octane is abtained through blending stocks to achieve the octane rating desired by using HIGH octane stocks such as Whole Alkylate, Toluene, Heavy Reformate and many others. RVP is also a big factor in blending gasoline. If you want to use Avgas in your lightning I suggest you mix it 1 gal of avgas to every 4 gal of super unleaded. This should give you an octane number of around 100. If you run straight avgas some type of lubricant should be added such as Marvals Mystery Oil, about 1 cap full per gal. I've been running avgas mixed with gas now for about 16 years and have never had any trouble with it. Detonation will destroy an engine and raiseing the octane or lowering the compression or your boost in this case, or retarding the timing is about the only things one can do.

 

OK, here's my .02.

I agree with usahooters, to a point.
Octane is not an additive, Tetra-Ethel-Lead (TEL), is an additive used to simulate a higher octane rating.
I do disagree with the notion of adding a lubricant to Avgas for use in an earth-bound vehicle. It is the high lead content, (read TEL), of the Avgas that is the problem, (toasted O2 sensors). I have NO idea what adding a lubricant to Avgas would, or should, do.

Nomex suit ON.

Jake...

 

Here we go again with "gasoline misconceptions 101"...

First, to answer the original question, it's Sunoco Ultra 94 exclusively. Highest octane commonly available pump gas, and it's right around the corner. Decent product turnover there, as well. Combustion knock is the enemy.

Now to address a few specific issues brought up in this thread:

1) Octane rating (expressed as R+M/2 in the US) is a measure of NOTHING other than resistance to detonation in a standard test engine. This is by definition. Other factors have reasonably well-defined relationships with octane (for example, energy content), but octane rating is STRICTLY a measure of knock/detonation resistance.

2) With very few exceptions (certainly applicable to anything you'll dispense through a pump), higher octane gasolines contain a lower energy content (on a mass basis, and possibly volume as well). Lower octane gasolines have a higher energy content. Diesel fuel delivers higher energy (BTU/lb) yet, but only clocks in at something like 60 octane or so. Jet aircraft, right up to the mighty SR-71, burn diesel fuel or a distillate quite similar (I realize that JP-1/2/3/whatever and diesel differ in certain ways).

3) If your engine is not pinging on your current fuel, you will not make any more power or go any faster by "upgrading" to a higher octane, unless your engine is SPECIFICALLY equipped to take advantage of the improved knock resistance "headroom" (by advancing timing, boost, or compresssion, or even possibly leaning out the mixture). It is a rare power plant indeed that can do this (I think that some turbo Saabs can compensate). Indeed, unnecessarily increasing octane will incrementally slow you down, due to the lower energy content of higher-octane fuels.

4) Going through some ridiculous gyrations involving spark plugs and low-octane fuel to "pass emissions testing" because "your buddy told you so" is simply idiotic. Internet research at its finest.

 

For those of you that are up to it here is a very comprehensive link on gasoline. . . . Best to have some chemistry knowledge to understand it all.

http://www.cs.ruu.nl/wais/html/na-di...faq/part1.html

 

I'm glad to see all the good threads posted about the gasoline here. It's not an OH BOY thing to me. Everyone has different opinions and each person can learn a little from reading each post. And your correct Silver-y2k-svt, diesel and jet fuel are one in the same basically and the lower octane number usually mean more BTU's or power, Hydrogen is used in Rocket fuel but has less BTU value than Natural gas hmmm. Jet fuel is really clean and water free and some are in gel form. Your also right when you say run the lowest octane gasoline you can for optimum power, its just I can't run anything less than 93 or I experience detonation to a small degree. I prefer to run avgas mixed as I said 1 gal to every 4 gal of super unleaded. This also dilutes the lead content way down, I have never had a sensor problem, not that I wont ever, but it works for me. As faar as adding the oil to (straight avgas) this is just to give some added lubricant not to change the octane number, such as you do to a 2 cycle engine. Its not a law just a trick I've learned and glad to pass on to anyone that wants to use it. Anyway things are cool and I hope I havn't agrivated anyone to much.

 

Hey TOC I think you said it all buddy. Thanks for the great link