MJMJ

I just noticed the sunoco that I go to has 100 octane race fuel, can I use that in my stock vette? Will it make it run better?

Just wondering!

JoesC5

First, is it leaded or unleaded?

If unleaded you can use it but you will be pissing away your money on a stock C6. If the highest octane you can get locally is 91, then you could mix in some of the 100 with the 91 and get 93 which can help your engines performance, especially in the hot summertime. If you have a Z06, then ending up with 93 or 94 will really wake up your engine compared to 91.

FloydSummerOf68

I wouldn't waste my time with it unless you're regular pump only goes to 100. Then it would be worth throwing in a few gallons of 100.

winters97gt

Not worth it unless you are tuned for it or you have a lot of power and want to air on the side of caution.

LS1LT1

There are a few stations south of here that also have 100 octane right at the pump which is super convenient for those that need/require that sort of thing, I am not among them of course.

lockman

the sunco here has it but it says right on the pump for off road use only.

LS1LT1

Hmm, that could mean that they won't (or legally can't?) even pump it into a vehicle that drives up to the pump right off the road.
Maybe they can only pump it into a gas can or only a race car that comes in on a trailer?

GeorgeZNJ

I normally run 10-20 roadcourse track days a year using 100 octane and I believe it may have contributed to the early retirement of my cats. There are some small regional airports here (S. Jersey) that sell low lead gas (100 @ 4.50gl)at half the price of unleaded(100@ 9.00gl), but they suggest no cats on the vehicle at all.

el es tu

leaded fuel fouls up cats, hence the offroad thing. but if you dont run cats, then it doesnt matter.

you could pump it into whatever you want at the places Ive seen out here. but considering how fast these cars eat up fuel, I dont think Id want to spend 100+ bucks on a fillup...

TTZ06VETTE

Could always go alky injection and have 120+ octane when you need it. For the price of a couple of fill ups you could get yourself a nice meth system!

JUIC3D

If I'm going for a PR and will be tinkering with the tune trying to get every last .001 out of the car, I'll splash in a couple gallons of 104 just to be on the safe side. I don't expect any major performance gains out of it as I'm not upping the boost or anything substantial like that, but it does give me peace of mind when really pushing the car to the limits.

Zip Corvettes

Why would you want to unless you ARE going to retune for it. 100 octane race fuel has a lower BTU then your normal 91 octane fuel. If you nothing but just change the fuel over you will lose power. The benefit of race fuel is that it does not pre ignite as easily as lower octane fuels. So because of this you can run way more timing, which is what give the power increase, but if you have a cal for race fuel and then fill up on say 91 octane you are going to have problems. Plus if you have cats you will kill those. I would stick with what you are running unless you are going to have your car on the dyno and cal it with the race fuel in the tank. That way you will also have your original cal when you are done running race fuel and want to go back to normal fuel.

JUIC3D

I make tweaks and adjustments to fuel/timing while at the track as well.

Zip Corvettes

That is fine, but you need to start on a dyno. You need to try and find your MBT. You can monitor your knock sensors but this is going to take longer. Depending on the octane you can a 10 degree increase in your timing numbers, but you don't want to just throw those in there without hitting a dyno first and creaping up to them.

JUIC3D

^ Very true.

glass slipper

Facts by proclamation are not sufficient here, please provide proof. I'll give you a little hint...the octane rating of a fuel is its resistance to igniting and that is all. It has no correlation to BTU content, flame speed, density, or any other characteristic of a fuel.

http://www.faqs.org/faqs/autos/gasoline-faq/part1/

Pay particular attention to chapter 6, especially at the end of section 6.3 where it says:

"The antiknock ability is related to the "autoignition temperature" of the hydrocarbons. Antiknock ability is _not_ substantially related to:
1. The energy content of fuel, this should be obvious, as oxygenates have lower energy contents, but high octanes.
2. The flame speed of the conventionally ignited mixture, this should be evident from the similarities of the two reference hydrocarbons. Although flame speed does play a minor part, there are many other factors that are far more important. (such as compression ratio, stoichiometry, combustion chamber shape, chemical structure of the fuel, presence of antiknock additives, number and position of spark plugs, turbulence etc.) Flame speed does not correlate with octane."

Zip Corvettes

Ok, BTU was a bad choice of words, just trying to keep it simple. The 91 octane had more "energy" then the higher octane race fuel. Did not say that the anti knock had a relation to the "energy" what I said was the advantage of race fuel was that you could add a significant amount of timing, thus increasing power. Basically the fuel itself was not increasing any power, if anything it would be less, but being able to increase the timing would give more power over running the lower octane vs. loss of energy by switching over the race fuel and adding timing. This can get so over done with facts and formulas that nobody will even understand what we are talking about. My fault for the use of a wrong term, but my reasoning is still the same. Wait doesn't the BTU directly relate to the amount of "energy" a fuel puts out. So I guess my original statement was correct. I am not directly relating the BTU of a fuel to the anti knock characteristics, I am simply stating the pros and cons of both fuels.

Zip Corvettes

re-Reading what you wrote, The BTU of the fuel was the correct term to use, but you are making it more difficult than what the OP originally asked. He is not building a new engine and asking what fuel should he use, he is using his stock engine with converters on it. The BTU of the race fuel is less than that of the lower fuel. The statement is true, because his original fuel is not a junk gas he will more then likely lose power by just switching over to the race fuel. Now if he is to modify his calibration to take advantage of what the new higher octane race fuel can give him, then he will indeed make more power. There is also a good article here you can read that simplifies it. They are basically stating that you just can't look for fuel that has the highest BTU rating either, there is more that goes into it when you want to get technical.
http://www.rockettbrand.com/techsupp...OfGasoline.pdf

Wow we really took this one around the bend. I have to get back to work.

JoesC5

Why would the 100 octane gas have less BTU then 91 octane unless it had a bunch of ethanol in it? I would think that with 100% pure gasoline, 100 octane would have the same BTU as 91 octane.

glass slipper

You said: "100 octane race fuel has a lower BTU then your normal 91 octane fuel." That is a direct correlation of BTU content to octane/anti-knock rating. BTW, BTU is energy so you're saying the exact same thing. But no matter how you say it, you're still wrong.

By making an incorrect statement, you are the one making it more difficult than what the original poster asked for. The link you provided has more to do with the flame speed of the fuel, you are now trying to correlate flame speed AND BTU content to octane which is incorrect...it's almost as if you didn't read the link I gave or the quote from it I put in my post. You're not arguing with me, you're arguing with facts. There are over 500 compounds used in the mixture of fuel so it can be blended to perform however you want. There's one high octane fuel made made by VP or Rockettbrand that'll increase HP in an engine built to run 87 octane by decreasing timing which goes counter to everything you're saying.

Good grief, you have to be the master of circular arguments.