xtroms

Got this in a email from Chevy:

While waiting for your car to gas up, you’ve probably stood at the pump and wondered about the differences between regular, plus and premium gasoline. At first glance, there doesn’t appear to be much of a difference, aside from price. However, some cars demand different fuel types for optimal performance and longevity. Here’s an in-depth look at the difference between fuel grades.

Octane numbers

Accompanying each fuel grade button, you’ll find a number — typically 87 for regular gas, 89 for plus and 92 or 93 for premium. This number is the fuel’s octane rating. High-octane fuel won’t pre-ignite or explode as quickly under pressure, making it ideal for performance cars and their high-compression engines.

When to choose regular

In the vast majority of vehicles, you’ll want to reach for the regular gasoline. This unleaded fuel costs less and functions well in low-compression engines, like the ones you’ll find in a standard economy car. If you opt for a higher-octane fuel, you won’t damage your vehicle, but you won’t see any benefits, either. It’s best to simply save your money and pick regular.

When to choose plus

Since plus-grade gasoline contains more octane than regular, it takes a higher-pressure engine to make it combust. If your vehicle is more than 20 years old, it might not have the technology to monitor and adjust the engine in accordance with the fuel’s octane levels. In these cases, plus-grade fuel may enhance your car’s performance. Additionally, some performance vehicles specifically demand plus-grade gas.

When to choose premium

If you drive a performance car, it may be tempting to save a few dollars by fueling up with regular gas. However, in the long run, this could be an expensive mistake. As mentioned before, lower-octane fuels combust more easily. In the high-pressure engine of a performance car, this can lead to engine knock. Engine knock isn’t just a noisy irritation — it damages your vehicle’s engine, reduces its performance and lessens its gas mileage. Therefore, high-octane premium fuel is the smarter choice for performance cars.

In most cases, you can depend on regular gasoline to keep your vehicle running. If you’re curious about your car’s needs, check the owner’s manual to make sure you’re fueling your vehicle properly.

robert miller

Nice write up man.. I always go by owners book I just run 93 all the time really not worth the diffs. Robert

Rayland

xtroms;

There are six types of fuel used in todays vehicles:

1) Gasoline or petrol is the most common fuel used in cars today.
2) Diesel fuel is widely used in transport vehicles, such as tractor-trailer trucks, buses, boats and trains.
3) Liquefied Petroleum, better known as propane, is a clean fuel alternative to gasoline.
4) Compressed Natural Gas or CNG.
5) Ethanol is a bio-fuel alternative to gasoline that's made from the conversion or sugar cane.
6) Bio-diesel is a substitute made from sugar beet, rapeseed or palm oil.

Perhaps you are referring to Petrol fuel grades?

Many thanks,

Ray

mschuyler

Hey Ray, I'm thinking that NO ONE except perhaps yourself was "confused" about what fuel was being discussed in Chevy's email, especially since they mentioned gasoline in the first sentence. Why you felt compelled to "school" us noobs in various other fuels available for other vehicles, but not the Corvette, is kind of a mystery.

Steve_R

Strange post Ray.

Maxpowers

I never understood why there is mid-tier (plus) fuel. I've only ever seen cars require 87 or 91+. Can anyone explain it?

Vetteman Jack

Good info sent out by Chevy. Only premium for my C7.

Obe1 GS

Ray, don't forget nitromethane - it too is used in vehicles

LDB

It got started in the transition to unleaded gas. At the time there were two grades, leaded regular and leaded premium. Cars designed for leaded gas could not use unleaded due to valve wear issues. Lead served as a valve seat lubricant, so when they went to unleaded, valve seats had to be upgraded. This required 3 pumps, leaded regular, leaded premium, and unleaded regular. Once the transition to unleaded was complete, we could have gone back to two grades, but the third pumps were already bought and paid for. So they were used to market a mid grade.

Maxpowers

^^^
Thanks. Makes sense.

Patman

I use mid grade a lot in my wife's BMW once summer is over and the weather starts to get cooler out. Her car calls for premium but she doesn't drive it hard at all and as long as the temperature is below 20C it is perfectly safe to run the mid grade. With the ridiculous price of premium up here now it saves us a lot of money by running midgrade (saves about 15 cents per liter!) as she drives about 30,000 km a year.

obxchartercaptain

Actually, in the 60's, various brands of gasoline had more then one grade...Sunoco for example....With the high performance muscle cars of that era with combustion ratios up past 14 to 1, Sunoco 260 with 100 octane was a must.

AZ99FRC

You left out the flux capacitor; totally necessary if you expect to time travel your vehicle properly!

LDB

In the 60’s a bit over half the premium was 98, most of the rest was 100, and a small amount went as high as 102. But those were R octane, which is 5 or 6 numbers higher than today’s required posting in (R+M)/2. Thus the most common 98 premium of those years was essentially the same octane as today’s 93 premium. While the 100 and 102 premiums back then were 1-4 numbers higher than today’s 93, they required lead to get there.

As far as number of pumps, I don’t remember Sunoco having 3 pump stations. I think they were the first to use blending pumps, so you could dispense several grades ranging from pure regular to pure premium. I don’t remember what octane their premium was, but I’d guess 100. I think the only guys who had 3 pumps were a few Gulf stations. The bulk of their premium was only 98, which was a marketing disadvantage for them since there was a fair amount of 100 out there. Rather than upgrade their refineries to make all their premium 100, they installed a third pump at some stations, and then sold regular, 98 premium, and a small quantity of heavily advertised 102 ultra premium.