I have a 2007 everything is still stock. Going to the drags
Would racing fuel be ok on a stock motor?

 

It would be pointless. You will spend multiple times what a tank of 93 octane costs and will gain ZERO horsepower, with the potential of losing power as most racing fuels burn slower.
And if you fill up with leaded racing fuel you will be looking at replacing your oxygen sensors and possibly clogging up your cats...

Absolutely not worth it on a stock car. Unleaded racing fuel is a good safety net on a highly modded / forced induction car, but won't do anything for you.

 

100%

 

We had this discussion before, the octane rating of a fuel has no correlation to flame speed in the combustion chamber.
http://forums.corvetteforum.com/c6-t...57-octane.html
Actually, it looks like we never finished it. My father passed away the day after my last post and I never got back to the thread. We can continue it here if you want and I'll leave out any references to "chicken little"...sorry about that.

 

Depends on what fuel you can get. My experience is I got knock retard on the 91 octane gas we can get in the West. So I typically mix in some 100 octane unleaded gas, just enough to get me around 94 to 95 octane whenever I go to the track. Then I pull the fuse to the computer to reset it and get it back to the high octane timing table.

 

Thanks for the replies guys, every thing you all said
I kinda figured but just wanted some more info from people
with more experience then me at doing this.

 

I am very sorry to hear that
Sure, I would love to hear some more about flame speed and octane rating. My understanding has always been that there is a general co-relation since most octane boosting compounds (MMT, Tetraethyl Lead, etc) bind up partially oxidized hydrocarbon chains and thus reduce the readiness of the fuel to combust.. I am sure you could get a highly leaded fuel or something with a high octane rating like pure Octane, or Toluene, Benzene, Xylene and add a combustion accelerator to it (say, Ethylene Oxide) and have something that has both a high octane rating AND a high combustion velocity, but, in general, wouldn't C16 burn slower than 100 octane unleaded and 100octane burn slower than 93 octane pump gas?

 

The octane number is not a measure of the amount of "octane" in gas as pure octane (C8H18 also referred to as n-octane, a "normal" or straight chain member of the paraffin family) has an octane rating of -17.

...H..H.H..H.H..H.H.H
....l...l..l...l..l...l...l..l
H-C-C-C-C-C-C-C-C-H would be Octane C8H18
....l...l..l...l..l...l...l..l
...H..H.H..H.H..H.H.H

Isomers of each normal member of the family have the same chemical formula as the normal member but with different molecular structure and properties. Isomers have the suffix "yl" added. For example, the name 2,2,4 trimethyl pentane is one specific isomer of octane. Tri means three and methyl means the radical CH3. So three methyl groups are attached to the pentane base (5 carbon atoms) at carbon atoms 2, 2, and 4 (numbered left to right) giving:


........CH3....CH3
....H....l...H....l...H
.....l....l....l....l....l
H--C--C--C--C--C--H
.....l....l....l....l....l
....H....l...H...H...H
........CH3
This is the structural formula for 2,2,4 trimethyl pentane or isooctane (you'll note it still has 8 carbon atoms and 18 hydrogen atoms just like n-octane). These terms are used synonymously since this particular isomer of octane is of importance in combustion engine work as you'll see below.

The critical compression ratio (or octane rating) of the parrafin family for audible knock in a spark ignition (SI) engine decreases rapidly as the length of the chain of the normal members is increased. The normal parrafins in the volatility range of gasoline are poor SI fuels due to very low octane ratings...remember n-octane has an octane rating of -17. Catalytically cracked fuels have branched parrafins (like above) making the carbon chain shorter resulting in higher critical compression ratios/higher octane ratings. The formula for the parrafin family is C(n)H(2n+2) giving methane (CH4), ethane (C2H6), propane (C3H8) etc.

Finally, the octane rating is a reference scale to measure SI knock and has been estabilished by arbitrarily selecting two primary reference fuels. They are isooctane (2,2,4 trimethyl pentane) which has been arbitrarily assigned an "octane rating" of 100 and n-heptane which has been arbitrarily assigned an "octane rating" of 0. The "octane rating" of a fuel is found by comparing its' knock intensity with various mixtures of n-heptane and isooctane. So an octane rating of 93 means a fuel has the same knock intensity in a standard CFR engine (google "astm CFR engine", you can vary compression ratio while it's running ) and at standard conditions is equivalent to a mixture of 93 parts isooctane and 7 parts n-heptane (by volume).

Lead in the old days delayed the preflame reactions to increase self-ignition temperature/detonation resistance and get octane ratings higher than 100. Adding the fuel octane would have the opposite effect. Read the link provided the thread from last Oct to get a better understanding of gasoline...there are over 500 different hydrocarbons that make up gasoline. While I don't propose to know the "secret" formulas used by gas companies, it isn't a two component fuel comprised of "octane and heptane". The lack of knowledge on the part of the "experts" you cite with respect to the chemical composition of gasoline should be enough to make anyone throw a huge BS flag on any claims they make.

Did you ever read the link I gave in the other thread? Here's a few links from Rockett Brand's website:
http://www.rockettbrand.com/techsupp...OrSlowBurn.pdf
http://www.rockettbrand.com/techsupp...ationships.pdf
http://www.rockettbrand.com/techsupp...rConfusion.pdf
http://www.rockettbrand.com/techsupp...tisfaction.pdf
http://www.rockettbrand.com/techsupp...tGasolines.pdf
Pay attention to the 3rd from the last and the last paragraphs.
http://www.rockettbrand.com/techsupp...olineMyths.pdf
Look at the #1 myth. I understand the authors of the books you cite have a lot of knowledge about certain things, but I think I'll take the word of people working for a company that makes money selling racing gasoline.
If you want to pick through their tech pages, here's the link:
http://www.rockettbrand.com/techsupp...bulletins.html
You'll note they have a 118 octane fuel that a bone stock 9:1 compression grocery getter engine will make more HP with simply because it's blended to have a much faster flame speed. Does a 9:1 engine need 118 octane fuel??? No, but you can reduce ignition timing and still make maximum cylinder pressure at the optimum ~12 degrees ATDC...the HP gain results from less negative work done by the piston as it approaches TDC on the compression stroke because the spark ignited the mixture later.

Actually, much is unknown as to exactly how MMT and TEL works but they do know the compounds increase the ignition delay of the fuel. This may be where confusion has come from as the term ignition delay does not refer to a time factor but the activation energy required to cause the reaction of oxygen and gas to complete (also referred to as combustion). The ignition delay term is just a fancy way of saying it takes a higher temperature to ignite the mixture.

Happy reading!