Gasolines and Fuel Additives...

[Ken]

In his book, Corvette Fuel Injection & Electronic Engine Management, Charles Probst states that

Fuels do vary though, from one refinery to the next. If you have trouble, try changing brands. As the folks at GM say: Usually, all a Corvette needs is a good-quality gasoline.

Hasn't that been what we've been trying to tell you all?

He continues...

Some cautionary words on supplemental fuel additives:

From GM's Research and Development: All major (fuel) brands contain detergent additives to keep injectors clean, and other additives to minimize intake deposits. Some 92-93 octane fuels have more additives than 87 octane. GM does not recommend continued use of supplemental fuel additives. Octane boosters, like toluene, can improve performance only up to engine capability. Overuse--adding more than 20% of the fuel--may cause adverse effects or damage original fuel-system components.

With '85-88 Bosch injectors, do not use cleaning additives in the gas tank. Fuel-system cleaners are not recommended, by GM, because of the kinds of materials used in the fuel tank bladder, fuel O-rings, and fuel line hoses. If cleaning is required, use the GM specified procedure. On the other hand, Multec injectors, in the '89-01 models, do not need cleaning, and doing so could damage them.

Also, Gordon Killibrew, of Late-Model Corvette Solutions, and former Corvette Action Center expert, told me that in '89-91 Corvettes, with Multec injectors, using any kind of supplemental fuel additives can cause a breakdown in the O-ring that separates the coil from the housing. This allows fuel to enter the injector coil, causing drivability problems, such as engine misses and roughness. The '92-01 injectors resist deterioration from these types of fuel additives though.

Again, as long as you are using a good-quality gasoline, there should not be a need for any type of supplemental fuel additive. The refineries will take care of that for you.

[Big Tex]

I understand about additives, but what about fuel grades? I was told that my '82 should drink only high octane. Is this true, and if so, why? What about an octane booster?

Yamaha did a test several years ago with their outboard motors and found that Chevron gas leaves less deposits and makes motors run better than other brands. Yamaha actually pays them a royalty for using Techralen (sp) in a fuel additive for outboards. All fuel brands are not the same...

[Ken]

All engines depend upon a certain octane of fuel in order to avoid detonation. What the article states is that the engine was designed with lower octane fuels in mind. The following is from my '87s Owner's Manual:

Your engine is designed to operate on premium unleaded fuel that meets ASTM specifications. Unleaded fuel must be used for the emission control system to operate properly. Use of fuels not meeting ASTM specifications could cause poor performance and increase emissions. The use of good quality fuels containg proper detergent additives is advised for good performance and emission control.

Using unleaded fuel with an octane rating lower than 87 can cause persistent, heavy "spark knock." ("Spark knock" is a metallic rapping noise.) If severe, this can lead to engine damge. If you detect heavy spark knock even when using fuel of the recommended octane rating, or if you hear steady spark knock while holding a steady speed on level roads, have your Chevrolet dealer correct the problem.

Yeah right, I'll run right off to my local Chevy dealer to get gas.

Anyhow, as you can see, the factory book states that you should use a premium grade fuel, but as long as it's from a good source, you can go as low as 87 octane and be just fine, saving a few bucks in the process.

[Edmond]

Wow, I didn't know that. I was always in the thinking that I would add a bottle of injector cleaner after every oil change.

Depending on gas prices, I will use plus or premium. But as of now, with premium being $2.30 a gallon, I've just left the Vette' at home in favor of the Camry