Finding the right fuel for your car is one of the biggest challenges if you’re not a backyard mechanic. Gas stations don’t make it any easier to figure out whether you need 87, 91, or 93 octane either. Thankfully Scotty Kilmer brings his decades of experience to this video to break it down for us all.
So what gas should you put in your car according to #savagescotty?
It breaks down like this:
- Only use the lowest octane recommended by the manufacturer in your manual to save money
- Higher octane gas only helps in turbocharged, performance, and old vehicles
- If you use regular gas and have no problems, don’t upgrade unless you find out it’s necessary
Let’s dive into why Scotty says you don’t always need the highest octane and how exactly to decide the right gas for your vehicle.
What Does High Octane Fuel Do?
Each gas station and fuel distributor sells a different precise blend of fuel and additives, so you never really know exactly what you’re getting. The octane ratings on gas are designed to tell you how resistant the fuel blend is to detonating too early in the engine. Early detonation leads to engine pinging, which causes damage to the cylinders.
High-performance vehicles with turbocharger systems generally need the higher octane since the extra compression increases the chances of this unwanted detonation. Basically, using high octane fuel keeps the explosive combustion in your engine right where you need it for power and performance.
Why Doesn’t Every Car Need High Octane Fuel?
High octane fuel does improve the performance of vehicles that require it by making sure the combustion occurs at the right time, therefore reducing lost power. Yet that doesn’t mean that every car will drive better or faster because it’s got 91 octane in the tank.
A budget sedan designed for commuting is unlikely to drive much differently if you fill it up with premium than regular unleaded. That means you’re just pouring unnecessary money into your gas tank at every fill up that could be better spent on mechanical maintenance and repairs. Using premium gas may keep a tiny amount of deposits out of the engine, but it’s not enough of a benefit to outweigh its costs for most drivers.
How Do I Tell if I Need Premium Gas or Not?
Of course, it’s not enough to guess if your SUV is considered “high performance” enough to demand premium gas. Simply grab your owner’s manual and read what’s recommended by the manufacturer. The manufacturer will generally tell you the lowest recommend octane, which is perfectly safe.
A car that needs 87 octane and up shouldn’t be filled up with 85 or E85 gas, but it won’t benefit from the higher octanes much either. Stick to the lowest octane rating and you’ll get both good performance and financial savings from your car. If you don’t have your owner’s manual, try checking for a copy online or calling a local dealership for your car’s make.
Most vehicles that require premium gas warn you inside the gas door, but they may not specify an exact octane and just call for premium. Check the manual to see if you can get away with using mid-grade or actually need the highest octane gas.
Old and worn-out engines tend to perform better with higher octane fuel because the compression has risen due to carbon deposits. Low octane fuel starts detonating earlier and earlier as the engine compression grows. However, this is a sign you need a carbon cleanout and some work on your car. Don’t just keep upgrading your gas octane to compensate since eventually the engine will become so clogged no fuel can help.
What about E85 Gas?
85 octane gas has been available in some parts of the country for decades because high elevation driving coupled with carburetor systems meant that some cars could perform on very inexpensive gas. Now you’ll mostly see this octane rating in E85 gas, which is a high ethanol blend designed only for flex-fuel cars. Unless you have a car that specifically says it needs E85 gas, don’t use it.
Older cars in particular can’t run the high ethanol mixture for long without developing expensive problems. Flex-fuel vehicles that can use E85 gas aren’t locked into using it though. E85 gas burns much cleaner and helps the environment, but you will find yourself stopping more often for fill-ups due to poor gas mileage. If you really need good mileage for a long trip, try skipping the E85 and save it for reducing the pollution of your daily commute. Switching back and forth won’t hurt your car unless it’s already damaged. In general, cars that can run E85 should only be filled with the next lowest octane since premium fuel won’t much of an improvement in their performance.
Filling up with high octane gas may help an old car run a little better, but it’s only a good idea on a daily basis for cars that require it. Stick with trusty unleaded regular gas to save money at the pump while still enjoying a smooth ride. Read up on Vehicle History to check out what kind of fuel any model you’re considering uses so you can budget out its fuel costs ahead of time.
