Gasoline

[Nick Palafox]

Hi all. It's been a while since I've visited this site. I have a question if anyone would be good enough to answer. I have a 2003 coup and since I've bought it I have always used premium gas. With the higher prices I'm thinking about running a lower grade thus cheaper. Any comments or suggestions? Thanks.

 

[jrose7004]

If I run the lower grade in my 98 Coupe it pings!

 

[DRTH VTR]

I would not suggest that for several reasons. The engine control system can compensate to some extent for lower octane fuel. However, it does so at least partly at a performance cost. I have seen "top tier" gasoline recommended as the only appropriate fuels, so budget brands are not appropriate, either. They may come at the cost of more deposits on valves, piston crowns, etc. It is just not worth it to me to scimp a couple of bucks on a tank of gas.

One of the Corvette Commandments is:

Thou shalt not feed thy Corvette budget grade fuel.

 

[Vettefan87]

People told me I was crazy, but my vette will not run on anything lower then 93 octane. Your car should be able to compensate, but when you have a vette does the cost of gas matter??

 

[RonJ]

I would not suggest that for several reasons. The engine control system can compensate to some extent for lower octane fuel. However, it does so at least partly at a performance cost. I have seen "top tier" gasoline recommended as the only appropriate fuels, so budget brands are not appropriate, either. They may come at the cost of more deposits on valves, piston crowns, etc. It is just not worth it to me to scimp a couple of bucks on a tank of gas.

One of the Corvette Commandments is:

Thou shalt not feed thy Corvette budget grade fuel.

On the money!!!

Ron ...

 

[LLC5]

Run high quality (Top Tier) 93 octane fuel, or park the car.

 

[XLR8]

My mechanic told me years ago to pay at the pump or pay at the garage. I took him at his word when I drove a Camaro. Since garage visits for a Corvette are very costly most of the time, I figure the advice is more solid than ever.

Make mine Chevron with Techron 93 octane Supreme - the same gasoline the big 3 automakers ship in to town special by tanker truck when it's time to do emissions testing!

JAG

 

[I_R_DA_ONE]

You can sneak by with a cheaper grade of gas once in a while but do not make a habit of it.....you will pay the price

 

[Nick Palafox]

Thanks for your advice!

I have always run top grade higheset level octane gas and based upon y'alls comments and advice I will continue to do so. I suppose I knew the answer when I asked the question but wanted confirmation from the group who would definitely know. Unfortunately I have two large SUV's as well, but thankfully they both run on regular. Thanks everyone for your replies!!!

 

[Robert YellowVette]

I have always run top grade higheset level octane gas and based upon y'alls comments and advice I will continue to do so. I suppose I knew the answer when I asked the question but wanted confirmation from the group who would definitely know. Unfortunately I have two large SUV's as well, but thankfully they both run on regular. Thanks everyone for your replies!!!

There was a long thread on this topic in one of the other forums, one guy who claimed to know since he was in the refinery business said all bulk gas is basically the same within its grade [minus batch variations] and the main difference is the tanker driver swiping his Texaco or Unocal card at the fill point.

The blending/payment software reads the card and delivers the appropriate blend of additives [eg, Texaco/Chevron, Unocal...] to the bulk gas being pumped into the tanker.

If he is an independent bulk tanker serving no name stations he gets the cheap default additive package added to the same bulk gas you are paying 15 cents more for at the 'top tier' gas stations...

Here in North Florida one large refinery serves most of the South East with the same bulk gas, and only the top tier labels have different gas additive packages. The cheap stuff at Billy Bob's Bait&Tackle&Chainsaw Rental single pump is basically the same gas.

The major reason to use Techron in Corvettes is the poor design of the fuel level sensors in the fuel tanks being corroded by sulfur in the fuel, I don't know if GM ever fixed that issue; kinda like the ECL that haunted us for the last 7 years despite the several recalls...

There is reason to believe the gasoline used for EPA testing by the Big 3 is a special blend not available to the public to simplify calibrating the test suite since regular pump gas has a fair amount of variance batch to batch even at the same refinery.

Sunoco does not have 89 AKI mid-grade tanks at their stations; they blend regular and premium at the pump to make the 89 octane...

I wonder if you could have only a single tank of 87 octane at a station and a smaller tank of 117 octane Xylene and just blend the other 2 grades at the pump...?

Xylene in refinery level amounts is less than 90 cents/gallon; a 78%/22% mix would give you 93 octane...

 

[XLR8]

The following was taken from the Chevron.com website and explains in further detail the assertions put forth by posters here:

About half of the cars and trucks on the road today have engines that are equipped with a device called a knock sensor. A knock sensor is designed to detect knock, often before the driver does. Upon sensing knocking or pinging, the engine’s computer control system (engine control module or ECM) adjusts the engine’s operation (retards the spark timing) to avoid the knock. These adjustments can reduce power and acceleration under certain driving conditions, especially under heavy acceleration when you want power the most.

Since excessive combustion chamber deposits can promote knock, they can also suppress your engine’s full potential by contributing to more frequent knock-sensor operation. "Top Tier" gasolines with higher detergency levels prevent harmful combustion chamber deposits, helping your engine maintain the maximum performance for which is was designed.

In certain sensitive engines, excessive combustion chamber deposits generated by lower quality gasolines can result in the top of the piston banging into the bottom of the cylinder head. This banging, called combustion chamber deposit interference, can produce a loud, unpleasant noise noticeable at cold start.

There is reason to believe the gasoline used for EPA testing by the Big 3 is a special blend not available to the public to simplify calibrating the test suite since regular pump gas has a fair amount of variance batch to batch even at the same refinery.

Good point, and probably true... There would have to be a standard calibration to eliminate batch variance influences on the test results. All the website says is that "Chevron gasolines have been used by the Big 3 for the 50,000 and 100,000 mile emissions system durability tests since 1973." I was
surprised to learn it starts at the Pascagoula, Mississippi refinery, is transported by barge up the Mississippi and Ohio rivers, then trucked from Louisville to Detroit.

JAG

 

[bobby1]

Use 100 octane union 76. 4.50 a gallon!

 

[grapeknutz]

The Corvette gods will remove horse power if you persist!

 

[JBsC5]

Be careful when trying to save a few dollars per fill. You don't want the cheaper fuels to ruin your fuel sending units...


Something with the sulfur in the fuel etc....

Better to buy high quality gas and eat macaroni and cheeze one night a week..(joking but you get my drift) Better to save elsewhere and not on buying cheaper lower quality fuel for the vette...

In fact buy Chevron or Shell or one of the other top tier fuels out there..

 

[JBsC5]

http://www.corvetteactioncenter.com/forums/showthread.php?t=61181&highlight=chevron

 

[Edmond]

The regular stuff goes in my Camry, that will take anything and run fine. However, it's premium or sitting in the driveway for the 'Vette.:L

Like it was said before, if you can afford a 'Vette, you should be able to afford to premium her.