OK here is my $.02. I am the former Manager of Automotive Events for Union 76 Racing (The circuit was grueling enough and then with post 9-11 travel, well let's say it's a young man's game)

Anyway: Winston Cup, Busch, Craftsman truck etc. use Union 76, 110 octane leaded racing gasoline exclusively. This very gas is available through distributors but legally can only be used off-road at sanctioned events.

Grand American (24 Hours at Daytona where 'vetts run) use Union 76 Competition 100. This is a specially blended, highly stable racing fuel that is street legal. It never goes in a pipeline, it is shipped in dedicated rail cars to four distribution points in the United States where it is picked up by distributors and shiped to tracks. This gas has been tested in Busch cars as a possible replacement for leaded gas (a little EPA pressure) and I have been told by engine builders that they get as much or more horsepower than with the 110. The nice thing about this gas it that it gets it's octane boost from the same chemical compounds as premium pump gas. Therefore if you blend it you acheive a linear relationship (ie. 75% 91 octane and 25% Competition 100 gives you 94 octane gas.)

What do I burn in my '99 C-5? Amoco Premium 93 (no alcohol) and then stop by Gas City here in the Chicago area for a splash of Competition 100.

If you want to try some 76 racing gas you can call 1-800-345-0076 and they will lead you to the nearest source. This is not a comercial, I no longer work for the company.

Just a side note: A surpriseingly large amount of Competition 100 is sold to fire departments and rescue squads because of it's stability for small engines (pumps, compressors, etc) Things that may sit for long periords of time then must start. (Winter storage?)

 

I recently switched to Chevron 93, from Racetrack 93 and my pinging/detonation went away completely.

 

There is a station down the street that sells 100. Can you use this all the time straight up or does it need to be mixed?

 

I am going to make a couple of guesses here and say most C5's, unless they are heavily modified, not only don't require 100 octane but will be worse off for using it. I have seen quite a few dyno tests and I have not seen any that show power reduction due to retarded timing caused by knock detection. That, usually means you have all the octane you need. But if, for some reason, you are experiencing pre igniton you can go up a few points to see if it stops. I do know that you can change your octane number by the ratio of the mix. In other words half a tank of the California 91 mixed with a half a tank of 100 will give you 95.5. But once you have a high enough octane number to stop pre iginition it is a wast to go any higher and will actually cause more deposits and less complete iginition.
Anyway that's my view of it. I sure would like to hear other people's thoughts.

 

I have noticed that I don't need anything more then 93 octane. I buy the 93 anywhere. Runs AWSOME on 93.


[Modified by 89NYFINESTVETTE, 5:27 AM 5/26/2002]

 

Amoco is my #1 choice, Chevron #2.

I wish I had 94 octane, but only 93 around here.

 

Unless you are experiencing pre ignition it won't make any difference will it?
:confused: :confused:

 

It's a different story here So CA.

I think the car's CPU has been adjusting the engine to avoid knocking for the lower octane we have here, I know for a fact that I can feel the difference when I mix 76 race fuel 100+ with Ca treehugger 91... after about a half of the tank is gone the car just runs better.. it's crisper and has better throttle response and makes more power. If I could get 93 or higher I wouldn't worry about it. I think there's more to it then just pre ignition.

 

I wish we had a sunco in florida.... :confused:

 

I usually go with Amaco. I have their card but I dont know what much difference it makes (I dont think I get any bonuses with the card...)

 

Now you do...Saw a few in Ft laud.

 

Just a quick follow-up to my above post. Two things based on my 29 years in the petroleum industry.....

NEVER by gas if you see a tanker unloading at the station. He is gravity dropping through a 4" hose into a tank of maybe 15,000 gallons. Almost all tanks have BS&W (industry term for Bottoms, Sludge, and Water). this inrush will stir everything up. The stations little filter on the dispenser (about the size of a screw-on oil filter may or may not stop the contaminants. You do NOT want BS&W in your 'vette

Secondly; Octane is grossly misunderstood. Union 76 Competition 100 is good for up to about 14 to 1 compression ratio. If you use more octane than you engine needs, you get no benefit. If you can only get 91 where you live you can blend a good 93 by adding some 100. As I said before it is a linear relationship. :flag

 

There's a time I've heard a guy on Radio said about no diff. in gas (87/91/or 93) :confused: so I ran out and tried 87 :rolleyes: 30 minutes later I noticed that my "check egine" stayed on :eek: After check the manual and then filled a full tank of 93 ... the "check engine" went off ... :cool:
Anyone out there using 87????
:cheers:

 

:seeya Hi from NY

 

any major bradn 93 and I havent noticed a diff this includes the overpriced sunoco ultra 94 , I prefer amoco usually though and I am thinking of gettin their card gives you gas rebates :yesnod: :seeya :chevy

 

FWIW, I was at a local Chicago area performance shop a month or so ago getting my car dyno'ed, and in passing the guy who owns the shop asked me what kind of gas I use (Amoco 93). He said that was a good choice, and suggested I avoid Shell because he'd seen a number of problems with it and questioned whether the local Shell 93 really was 93 octane.

Coincidentally, I used to use Shell 93 about 10 years ago, and found that my cars seemed to run better on Amoco...

 

I've yet to hear anyone mention Marathon-Ashland brand 93. That's what I use, mainly because I have their card. I tried Amoco Ultimate once and couldn't tell too much difference. So anyone heard if Marathon premium has a decent additive package?

 

Mobil 93 Plus for this Corvette! Plus, the stations are everywhere down here and easy to find. Peace. :cool: T-Bone.